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What Is Cancer?

Cancer is the uncontrolled growth of abnormal or damaged cells that can start anywhere in the body and potentially spread to other areas.1

The body is made up of trillions of cells. Normally, old or damaged cells die daily, and they're replaced with new, healthy cells. With cancer, this process short circuits. Instead of dying, abnormal cells grow and divide when they shouldn't.1

Cancer falls into two categories:2

  • Solid tumor cancers. Possible in any organ; common places include the breast, lung, prostate, and colon
  • Hematologic (blood) cancers. Lymphoma, leukemia, multiple myeloma, as well as less common forms of blood cancer

Causes and risk factors for cancers may differ, depending on the type of cancer and the cancer patient. Fortunately, treatment options exist to help patients living with cancer.2

Cancer vs. Tumor

Is a Tumor Always Cancer? 

No, some tumors are benign (noncancerous). These types of tumors typically don’t spread to other locations in the body.3 On the other hand, not all cancers cause tumors. For example, tumors typically don't occur with blood cancers. With these conditions, cancerous cells travel around the body via the bloodstream.1

What Is a Tumor?

A tumor is the uncontrolled growth of cells that become a mass. It may or may not be cancerous.3 These masses can form anywhere, but they usually develop in solid tissue, such as bone, muscle, or organs.1 They are different from cysts—small sacs filled with air, fluid, or solid material—that are mainly benign (noncancerous).3,4

Tumors can either be benign or malignant (cancerous).3

These typically slow-growing tumors have clear-cut borders,5 and they don't spread into other tissues or appear in other areas of the body (metastasize).2,3 Most benign tumors aren't life threatening.3 Still, a benign tumor can press on tissues, which can lead to pain or health complications.5

Benign tumors that cause such complications, as well as those that could eventually become malignant, are typically removed surgically when feasible. Most don't return.5

Malignant tumors typically have uneven borders.5 They can breach nearby tissue by metastasizing (spreading) through the bloodstream or lymphatic system to form secondary tumors.3,5 Solid malignant tumors that initially form in the cells that line organs are called carcinomas;1,6 ones that initially develop in the muscle, bone, or tendons and ligaments are called sarcomas.1

Treatment depends on a number of factors, including the type and size of the tumor and whether it has spread to other areas of the body.7 If the malignant tumor is localized to one area, sometimes surgery may be an option by itself. If the cancer has spread, or is not treatable by surgery alone, additional treatment options might be suggested, including but not limited to chemotherapy, radiation therapy, or other drug therapies, for example.7,8

Prevalence of Cancer

In the United States, cancer is projected to affect approximately 1 in 3 people in their lifetime.2 In 2020, there were more than 2.2 million new cases of cancer in the U.S..9 By 2050, the Centers for Disease Control and Prevention (CDC) estimates the total number of U.S. cancer cases will increase by 49% as a result of the growing and aging population.10

Causes and Risk Factors

What Causes Cancer
What Causes Cancer?

Evidence suggests that cancer may stem from a combination of factors, such as genetics and a person’s environment.1

Cancer may begin when cells either ignore or don't receive the signal to stop growing or die. Instead, they continue to divide and develop into a tumor. Just like organs, tumors need nutrients and a blood supply to survive. As they enlarge, they send out signals for angiogenesis—the development of new blood vessels.11


Cancer and Genetics

Is cancer hereditary? Yes and no. Parents can’t directly pass cancer to their children, but some cancers seem to run in families, and there are instances when inherited genetics changes can increase the risk of cancer.12

Genes carry the blueprint for how the body should make the proteins that control cell growth. Some genetic mutations can prompt uncontrolled division. They can also cause problems in proteins responsible for cell repair.12

If sperm or egg cells carry these mutations, they may sometimes be passed from parent to child, copied into every cell in the body.13 These are known as germline mutations.13 Inherited gene mutations are estimated to contribute to 5% to 10% of all cancers.13 Inheriting a gene mutation doesn't guarantee the child will one day develop cancer, but it may increase their risk.13 For example, a child may inherit a faulty BRCA1 or BRCA2 gene from a parent and have an increased risk of developing several cancers.12

Cancer Risk Factors

Several cancer risk factors are associated with disease development, including:

  • Cancer risk increases with age. About half of all cancer cases occur in people older than 66.14

  • Worldwide, alcohol is tied to nearly 750 ,000 cancer cases diagnosed per year.15 Greater alcohol consumption increases the risk for certain cancers, including esophagus, liver, breast, mouth (excluding lips), throat, and larynx. A person’s risk of alcohol-related cancer also increases the more they drink over time.16

  • Chemical exposure, which may occur at work or at home, can increase cancer risk. There are more than 200 substances that may raise the risk of cancer,17 including:18

    • Arsenic
    • Asbestos
    • Benzene
    • Beryllium
    • Vinyl chloride
  • Inflammation is one of the body's responses to infection or injury. It's intended to help patients heal. However, chronic inflammation is inflammation that continues or occurs in absence of injury or infection and can damage one’s body. Over time, it can damage one’s DNA, tissues, and organs, increasing the risk for cancer. For example, people with ulcerative colitis and Crohn’s disease, two chronic inflammatory bowel diseases, may develop a higher risk of colon cancer.19

  • Although some compounds can be carcinogenic, most studies lack definitive proof that specific foods directly cause or prevent cancer. However, the risk of developing some cancers does increase with heavy alcohol consumption.20

  • Estrogens are part of important physiological functions in people assigned male at birth and in people assigned female at birth. They also have been linked with an increased risk of different cancers.21 Patients weighing hormone therapy should discuss potential risks and benefits with their healthcare professional.21,22

  • A weakened immune system makes fighting cancer harder and raises the risk of developing some cancers. Transplant patients who take immunosuppressive drugs to avoid organ rejection can be at greater cancer risk.23

  • Some bacteria, viruses, and parasites can cause cancer to develop or increase the risk of developing it. Some cause chronic inflammation that may increase risk of developing cancer. Certain viruses can disrupt the signals controlling cell growth. Certain infections can overtax the immune system, leaving the body more susceptible to other cancer-causing infections.24

  • Being overweight or having obesity increases the risk of several types of cancers, including breast, colon, uterine, liver, pancreatic cancers and multiple myeloma.25 In the United States, higher than healthy body weight is linked to 11% of cancer cases for people assigned female at birth and 5% of cancer cases for people assigned male at birth.26 Being overweight or having obesity is associated with several changes in the body that may promote the disease:25

    • Elevated insulin-like growth factor
    • Increased insulin
    • Long-lasting inflammation
    • Increased sex hormone levels
  • Some high-energy radiation can damage DNA and lead to cancer. While X-ray imaging, computed tomography scans, and positron emission tomography scans can all cause some degree of cell damage, there is low risk that these medical procedures will lead to cancer. Patients should talk with the doctor before undergoing any of these procedures.27

  • Ultraviolet rays from the sun, tanning booths, and sun lamps can all cause cell damage, potentially leading to skin cancer. Exposure can impact people with all types of skin tones.28

  • As much as 90% of lung cancer cases stem from smoking tobacco, but tobacco use overall may lead to cancer in any part of the body. Tobacco smoke contains approximately 70 cancer-causing chemicals, many of which can damage DNA. Cells with damaged DNA may develop abnormally and lead to cancer.29

Biological Causes

Infections from some bacteria, viruses, and parasites can increase the risk of developing certain cancers.30 For example, by entering previously healthy cells and interfering with genes that dictate growth, infection with viruses can lead to possible cancer development. Infections may result in chronic inflammation or immune system suppression, resulting in increased risks for certain cancers. Overall, these infections are associated with approximately 15% to 20% of cancer cases worldwide, though that figure is likely smaller in the United States because of factors such as the higher prevalence of some infections in developing nations.30 Some viruses associated with increased cancer risk include:31

  • Human papillomavirus (HPV)
  • Hepatitis B
  • Hepatitis C
  • HIV
  • Epstein-Barr virus
  • Kaposi sarcoma herpesvirus
  • Human T-cell lymphotropic virus type 1


Cancer Prevention

Some lifestyle changes may help reduce the risk of cancer. The options may not be appropriate for everyone and should always be made in consultation with a doctor. Potential options include:

  • Stopping tobacco use32
  • Managing weight32
  • Engaging in physical activity, for example 150 minutes of moderate aerobic activity a week33
  • Protecting oneself from the sun; staying in the shade, covering one’s skin, using sunscreen, and avoiding sources of ultraviolet radiation, such as tanning beds and sun lamps28,32
  • Talking to a healthcare provider about vaccines against infections that are associated with increased risk of developing certain cancers34
  • Avoiding risky behaviors; practice safe sex, avoiding shared needles31

So far, research is inconclusive as to whether specific food choices either lead to or prevent cancer.35

Types of Cancer

Cancer isn't one specific disease. There are many types of cancer that can appear anywhere in the body. Some are more common than others.1

Some types of cancer include:

  • After skin cancer, this is the most common cancer affecting people assigned female at birth in the U.S., with a 13% lifetime breast cancer risk and nearly 300,000 new cases of invasive disease diagnosed annually.36 Although breast cancer is more common in those assigned female at birth, people assigned male at birth can also develop the disease.37 There are multiple types of breast cancer, and the median age at diagnosis for those assigned female at birth is 62, meaning there are as many patients above as there are below the age of 62.36 Gene mutations that pass from parent to child are linked to between 5% and 10% of breast cancer cases. Mutations of BRCA 1 or BRCA2 genes are common causes of these hereditary breast cancer cases.38 Learn more about Breast Cancer.

  • This cancer affects the cervix, the lower part of the uterus that connects to the vagina.39 An estimated 14,00 0 new cases of cervical cancer may occur annually in the U.S.40 About 91% of cases may be linked to human papillomavirus (HPV) infection.41 Early changes of the cervix can develop into cancer.39 Pap smear screenings can help catch pre-cancerous changes in the cervix or early cases of cervical cancer.40 People with cervixes have a 0.7% lifetime risk of cervical cancer.42

  • Colorectal cancer begins in either the colon or the rectum. Healthcare professionals will classify the cancer as colon cancer or rectal cancer based on where it starts. Since these cancers share commonalities, they are often referred to together as colorectal cancer.43 Colorectal cancer is the third most common cancer diagnosis in the U.S. when excluding skin cancer diagnoses. The American Cancer Society projects 106,970 new cases of colon cancer in 2023, and 46,050 new cases of rectal cancer.44 Rates of colorectal cancer among two groups of adults have been on the rise in recent decades. Among adults between the ages of 20 and 39, the number of colorectal cancer cases has been climbing since the mid-’80s. And among adults between the ages of 40 and 54, the number of colorectal cancer cases has been rising since the mid-’90s. The younger cohort has seen the biggest increase in the number of cases.45 Colorectal cancer usually begins as growths, referred to as polyps, in the lining of either the colon or rectum.43 The lifetime risk of colorectal cancer for all genders is roughly 4%.44 Learn more about Colorectal Cancer.

  • This cancer develops in the cells that line esophagus or in glandular cells in the esophagus.46 Approximately 21,000 cases are expected annually, accounting for 1% of cancers nationwide.47 Esophageal cancer affects people assigned male at birth more than those assigned female47 and has been linked to smoking, alcohol consumption, chronic acid reflux, and HPV.48

  • This cancer occurs in tissues that produce blood, such as the bone marrow and lymphatic system. There are multiple types of leukemia, with some more common in adults and others in children.49 Experts estimated 60,650 new cases of leukemia in 2022 and 24,000 deaths, accounting for 3.9% of all cancer deaths.50 Some leukemia risk factors include genetic disorders such as Down syndrome, exposure to chemicals like benzene, a family history of the disease, smoking, or previous cancer treatment.51 Symptoms may include fatigue, fever, night sweats, bruising or bleeding that occurs easily, weight loss, loss of appetite, and petechiae (small red dots occurring beneath the skin, caused by bleeding).52 Learn more about Leukemia.

  • This cancer is the leading cause of cancer deaths.53 In the U.S., about 240,000 new cases of lung cancer are expected in 2023, making it the second most common type of cancer, not including skin cancer.53 The average age of patients diagnosed with lung cancer is 70, and it’s rare in people younger than 45.53 People who smoke face the largest lung cancer risk. The length of time spent smoking and the number of cigarettes smoked increase the likelihood of lung cancer.54 In the U.S., approximately 10% to 20% of lung cancers each year, develop in people who never smoked or who smoked fewer than 100 cigarettes total in their life. Researchers suspect that secondhand smoke helps cause around 7,300 of these cancers and that radon helps cause around 2,900 of them.55 Some symptoms include a cough that doesn’t clear up, a cough that produces blood, difficulty breathing, and chest pain.54 Learn more about Lung Cancer.

  • Lymphoma is an umbrella term for cancer that affects some of the cells in the lymph system. The lymph system is a network of organs and tissues that creates, stores, and distributes white blood cells to combat diseases and infections. This system includes lymph nodes, lymphatic vessels (the network of tubes that carry white blood cells and lymph fluid), bone marrow, the spleen, and the thymus.56,57,58 In 2019, the CDC estimated that there were 2.5 new cases of Hodgkin lymphoma for every 100,000 Americans.59 The estimate stood at 18.1 per 100,000 the same year for Non-Hodgkin lymphoma.60 Hodgkin and Non-Hodgkin lymphoma symptoms include swollen lymph nodes in the groin, armpits, or neck; fatigue that doesn’t improve; itchy skin; night sweats; unexplainable weight loss; and shortness of breath.61,62

  • In the U.S., multiple myeloma has a lifetime risk of 1 in 132 (0.76 %).63 About 35 ,730 Americans are expected to be diagnosed with multiple myeloma in 2023, and the disease is estimated to kill about 12,590.63 This cancer occurs in plasma cells, a type of white blood cell. These cancerous plasma cells can build up in bone marrow, producing harmful proteins instead of useful antibodies. Some signs and symptoms include bone pain, weakened or broken bones, low red and white blood cell counts, low platelet counts, high levels of calcium in the blood resulting in excessive thirst or increased urination, back pain that comes on suddenly, leg numbness, muscle weakness, dizziness or confusion stemming from hyperviscosity (a thickening of the blood), kidney issues, and an increased number of infections.64

  • This condition is the fifth most common cause of cancer-related death in people assigned female at birth.65 Although it affects the ovaries, it has been linked to the same BRCA1 or BRCA2 genes associated with breast cancer.66 Approximately half of those diagnosed with the roughly 20,000 cases of ovarian cancer diagnosed annually in the United States are 63 or older.65 Symptoms include the need to urinate frequently, a persistent urge to urinate, difficulty eating, feeling satiated quickly when eating, pain in the belly or pelvic region, and bloating.67

  • Initial signs of pancreatic cancer are subtle, making detection of the malignant tumor in the pancreas difficult. Jaundice is a common pancreatic cancer symptom, and it’s typically one of the first.68 The American Cancer Society projects about 64,050 new cases of pancreatic cases in the United States in 2023.69 The average person has a 1 in 64 lifetime risk for developing the disease.69 Type 2 diabetes, certain chemical exposures, smoking, obesity, and chronic pancreatitis increase the risk.70

  • After skin cancer, this is the most common cancer in those assigned male at birth, and it’s mainly slow growing.71,72 Prostate cancer symptoms include pain during ejaculation; pelvic, back, or hip pain that does not improve; painful urination; trouble with emptying the bladder; frequent urination, particularly at night; difficulty maintaining a steady stream of urine; and challenges initiating urination.73 Overall, people assigned male at birth have a 1 in 8 lifetime risk, and more than 288,000 prostate cancer cases are diagnosed annually in the U.S.72 Learn more about Prostate Cancer.

  • This is the most common cancer affecting all genders.74 Roughly 9,500 people are diagnosed daily in the U.S., and 1 in 5 Americans will develop it.75 Skin cancer can occur in three different types of skin cells: squamous cells, basal cells, and melanocytes. Cancer in the basal and squamous cells are the most common types of skin cancer and can typically be cured. Melanoma, which affects the melanocytes, results in the most deaths because it tends to reach other areas of the body.76

  • The average age of patients diagnosed with this rare cancer is 33, with approximately 6% of cases affecting children and teens, and 8% of cases affecting people over the age of 55. Roughly 9,000 cases are diagnosed annually in the U.S., and people in the at-risk population have a lifetime risk of dying from the disease of about 1 in 5,000.77 Most cases originate in germ cells, which are responsible for producing sperm.78 Typically, it’s highly treatable.77

  • This cancer affects the butterfly-shaped gland in the throat that regulates heart rate, how food is metabolized into energy, and body temperature.79 According to one study, those assigned female at birth are more than four times likely to receive a diagnosis for papillary thyroid cancer than those assigned male at birth.80 Approximately 43,800 cases are diagnosed annually in the U.S.81 Increased hoarseness and difficulty swallowing are common signs.82

Some cancers never move beyond their original location (the primary site). These are called localized cancers. Cancer that spreads beyond the primary site to other parts of the body is metastatic cancer.83 It's considered advanced cancer, and signs may include:83

  • Extreme weakness and fatigue
  • Unintended weight loss
  • Pain
  • Shortness of breath

Metastatic cancer cells detach from the tumor and travel through the body via the bloodstream or lymphatic system.83 Most cells die, but some settle in a new location (frequently, but not always, the nearest organ) and continue growing.83

Although it grows in a different location, metastatic cancer is still named after the primary site. For example, breast cancer that spreads to the lungs is called “metastatic breast cancer” not “lung cancer.”83 Doctors choose treatments that consider the primary site when treating the metastatic cancer, too.83

Cancer Symptoms

Cancer Symptoms

Some signs and symptoms of cancer are common across all types of cancers and patients. These symptoms often are not indicative of cancer. But, if you’re experiencing any of these symptoms and they have not improved or they have worsened, talk to your doctor to identify the cause. Some of the possible cancer symptoms include:84

  • Extreme fatigue
  • Unintended weight loss of more than 10 pounds
  • Loss of appetite
  • New, unexplained pain
  • Skin changes (sores, jaundice)
  • Persistent cough and hoarseness
  • Unexplained bleeding or bruising
  • Bladder and bowel changes
  • Headaches
  • Vision and hearing problems

Some gynecological cancer symptoms include:85

  • Abnormal bleeding from the vagina
  • Trouble eating or feeling full quickly when eating
  • Pain in the abdomen or back
  • Pain in the pelvis
  • Feeling the need to urinate frequently
  • Constipation
  • Tenderness, pain, burning, or itching of the vulva
  • Changes to the skin of the vulva

Some testicular cancer symptoms include:86

  • Testicular swelling
  • Testicular lump
  • Breast growth or breast soreness
Childhood Cancer Symptoms

Sometimes it can be difficult to spot cancer in children immediately because the symptoms are often similar to other types of sicknesses or injuries. While childhood cancer is uncommon, a doctor should review any of these symptoms, which could be cancer but are probably related to something else:87

  • Unexplained swelling or lump
  • Unexplained paleness or loss of energy
  • Continuing pain in one spot
  • Unexplained fever
  • Frequent headache
  • Easy bleeding or bruising
  • Sudden vision changes
  • Unexpected weight loss

Diagnosis and Treatment

Cancer Diagnosis

With cancer, early detection is key to better patient outcomes. However, not every cancer is identified before it grows. Consequently, doctors need a way to determine the extent of the disease.

  • To evaluate your cancer, doctors may use a four-stage system. Once cancer is detected, it is commonly categorized into one of these stages. Determining cancer stage helps healthcare providers plan the best course of treatment, determine the seriousness of the cancer as well as prognosis, and select potential clinical trials:88

    • Stage 0: A test has revealed abnormal cells, but they haven’t reached other organs or tissue that are close by. Sometimes healthcare providers call Stage 0 cancer carcinoma in situ (CIS). CIS could become cancer later, but is not cancer at the time of discovery.
    • Stages 1-3: A test has confirmed the presence of cancer. Higher stage numbers indicate increased spread of the cancer, or larger tumor size.
    • Stage 4: Cancer has traveled to parts of the body that are far from the original site.88
  • Cancer diagnosis and detection may beg in when a patient reports cancer symptoms or a test shows some evidence of cancer. The next step may involve lab tests and imaging studies.89

    In a lab test, a clinician will collect a sample of blood, urine, other bodily fluid, or tissue for analysis. Some tests can give specific information about health concerns. Others may provide only a general picture of what underlying health issues could be causing issues.89 Some of the lab tests used in cancer diagnosis include:

    • Blood chemistry test: Establishes the quantity of substances that are circulating in blood89
    • Cancer gene mutation testing: Establishes whether a person has inherited genetic mutations that can lead to cancer90
    • Complete blood count (CBC): Establishes the quantity of specific types of blood cells, such as platelets, white blood cells, or red blood cells; or measures the quantity of hemoglobin, among other possible areas of investigation89
    • Cytogenetic analysis: Assesses changes in the structure or number of chromosomes in the blood89
    • Sputum cytology: Detects abnormal cells in mucus and other matter captured from coughing.89
    • Tumor marker testing: Tumor marker tests can identify substances made by cancer cells in high quantities. These markers give information about the tumor, cancer type, or treatment options.89
    • Urinalysis: Assesses urine color and contents, including types of blood cells89
    • Urine cytology: Helps identify the presence of cancer cells in the urinary tract89
  • Lab tests rarely give doctors thorough details. Imaging studies, which can paint a more informative picture, include:89

    • CT scan. These scans may be useful in some situations to determine a tumor's size, shape, and location. CT scans can also reveal blood vessels that connect to tumors. Doctors may also use CT scans to study if or how a tumor changes over time.91
    • Magnetic resonance imaging (MRI). This radiation-free scan can analyze your soft tissue and detect if your cancer has spread. It may also help doctors make decisions about how to treat cancer. The test creates images of the body, rendered in cross-sections. This can help doctors locate some cancers.92
    • PET. Positron emission tomography (PET) scans use a substance called a tracer to identify cancer in the body. The tracer is radioactive and administered with an IV, often inserted on the inside of the elbow. Once the tracer circulates throughout the body, it helps doctors better see organs and tissues that cancer may have reached.93
    • Bone scan. An imaging test used to determine the presence of bone tumors or cancer in bones, this scan uses a radioactive substance that is injected. The substance allows healthcare providers to better see and evaluate the bones.94
    • X-ray. X-rays can produce images of bones, as well as certain tissues and organs. Mammograms are a common type of X-ray used in cancer detection, specifically for identifying breast cancer. Sometimes, doctors will order a type of X-ray called a contrast study, which uses an iodine-based dye or other substances, such as barium. Contrast studies can show certain organs in better detail, which may be useful in scanning for cancer in other parts of the body.95 
    • Ultrasound. Ultrasound uses sound waves to produce images of organs and tissues inside of the body. It can reveal things that X-rays can’t, and it does so without radiation. For example, an ultrasound may help a doctor differentiate between a cyst that’s filled with fluid and a solid tumor. Each will appear differently in the ultrasound results. While an ultrasound can reveal the presence of a tumor, the test can’t be used to determine whether a tumor is cancerous. Doctors may also use ultrasound to guide a needle for a biopsy.96
    • Cancer biopsy. A biopsy removes tumor cells or tissue so they can be tested in a lab.97 Samples can be captured via:
      • Needle biopsy: Using a needle, clinicians remove tissue or fluid to study under a microscope.98
      • Endoscopic biopsy: Involves a long, flexible tube with a light at the end to study inside of the body. Doctors can use a needle that is passed through the endoscope to remove tissue samples for analysis.99
      • Skin biopsy: Involves removing cells from the surface of the skin for analysis. A skin biopsy can detect melanoma.100
      • Bone marrow: Identifies issues with blood, including cancer. A bone marrow biopsy, which involves obtaining a sample of bone marrow from the hip bone with a long needle, can help identify leukemia, lymphoma, and multiple myeloma.101,102
      • Surgical biopsy: A surgical biopsy involves making an incision to collect cells for analysis. Surgeons may remove a piece of a lump or suspicious tissue for analysis, or they might remove the entire lump or area.103
Cancer Treatment

There are many types of cancer treatments. A doctor can help to decide which may work best. They include:

  • Chemotherapy can slow or stop the growth of cancer cells. Doctors may use it to treat cancer, slow its growth, or lessen the likelihood of it returning. Or chemotherapy may be used to shrink tumors that may be painful or are causing other problems. Chemotherapy can be administered alone or in combination with other types of cancer treatment. The approach largely depends on the type of cancer a person has, as well as the extent of the cancer’s spread. Chemotherapy may be used at different times during the cancer treatment journey, such as before surgery or radiation to make a tumor smaller, after surgery or radiation to eliminate cancer cells that remain, or to combat cancer cells that have returned at a later time.104

  • Radiation therapy for cancer uses high-dose radiation to kill cancer cells. It slows tumor growth by damaging its DNA. Over several weeks or months, tumor cells die and are eliminated from the body.105

  • Immunotherapy cancer treatment uses part of the immune system to attack the cancer. Immunotherapy can boost the immune system, helping it to attack cancer cells more effectively. Or it can involve lab-made substances that act similarly to natural aspects of the immune system. These lab-made substances then help the immune system to attack cancer.106

  • Monoclonal antibodies are lab-made proteins that act similarly to the ones that the human body produces naturally. These proteins can be designed to target specific cancer proteins, called antigens. This means that, for a monoclonal antibody to work, researchers must first identify the correct antigen to target. While some monoclonal antibodies target specific cancer antigens, others boost the immune system to better attack cancer cells.107

  • These lab-manufactured antibodies can bind to two different antigens simultaneously. Bispecific antibodies are the focus of current cancer treatment and imaging research.108

  • Targeted therapies target proteins responsible for cancer cell growth and division as well as spread. The umbrella term “targeted therapy” can apply to small-molecule drugs or monoclonal antibodies. Small-molecule drugs can enter cells and target their contents.109

  • There are vaccines that prevent diseases that can lead to cancer, and there are vaccines that treat cancer itself. The HPV vaccine as well as the hepatitis B vaccine are examples of the former. Vaccines that treat cancer help generate an immune response to fight the disease. These vaccines may be comprised of cancer cells, components of cancer cells, or antigens. Sometimes, a patient may receive a cancer vaccine created from their own immune cells, which have been removed then exposed to substances in a lab to yield the vaccine, which is then injected.110

  • Gene therapy repairs or adds to human genetics to combat cancer. Gene therapy can also condition the immune system, training it to destroy cancer cells or protect healthy cells from cancer therapies.111

  • All blood cells start as immature cells, called hematopoietic (blood-forming) stem cells. These young cells, which mostly reside in bone marrow, can become whatever type of blood cell that the body needs. Once they reach maturity, they leave the bone marrow and circulate in the bloodstream. Cancer or cancer treatment can sometimes destroy stem cells, leaving a person unable to produce new blood cells. A stem cell transplant or bone marrow transplant can help. Transplanted stem cells, which are sometimes obtained from a donor’s blood, can grow into healthy blood cells. With a bone marrow transplant, marrow is taken from a donor’s bones, frequently the pelvic bone, filtered, then given to the patient similarly to how they would receive a blood transfusion. These stem cells then reach the bone marrow, where they begin to make new blood cells.112

  • Complementary and Alternative Medicine (CAM) fall outside of the standard of medical care, but they may be useful in helping cancer patients deal with unpleasant side effects from treatment, may provide psychological comfort, or may empower patients. Complementary medicine is care that accompanies standard cancer care but is not the standard treatment. For example, some patients may turn to acupuncture to reduce standard treatment side effects. Alternative medicine is treatment that takes the place of standard medical care. For example, someone might turn to a specific diet to treat their cancer instead of following an oncologist’s treatment guidance. Less research has been devoted to complementary and alternative medicine than standard medical care. Some types of CAM have been determined to be safe and effective, such as mediation, yoga, and acupuncture, among others. Others, however, may be ineffective or could create harmful interactions with cancer medications. Talk to a healthcare provider before beginning any type of CAM.113

Global Impact of Cancer

Global Impact of Cancer

According to the World Health Organization, cancer is a leading cause of death worldwide. Roughly 23 million new cases were reported in 2019. Approximately 10 million lives were lost in 2020, mostly to breast, lung, colon, rectal, and prostate cancer.114,115

Significant disparities exist in low- to middle-income countries. By 2040, it's anticipated these nations will shoulder two-thirds of the world's cancer burden.114 For example, one study assessed the global cancer burden across different socioeconomic groups between 2010 and 2019. The study revealed that people in the lower quintiles of the sociodemographic index saw the largest percentage increases in the incidence of cancer, as well as mortality from cancer. In other words, people with the fewest resources experienced more cancer and more cancer deaths.114

The exact global cost of cancer care is unknown, but in 2015, estimates for cancer-related direct medical costs were $183 billion in the United States.116 By 2030, that amount is projected to increase to $246 billion.116

Frequently Asked Questions About Cancer

  • Different factors may determine whether a person’s cancer can be cured. They include cancer stage and the treatment they receive, among others. It’s also important to understand the difference between the terms cure and remission. Cured means that the cancer has resolved with treatment, that it won’t come back, and that no additional treatment is required. A doctor can seldom be so sure that cancer will not return. Often, the longer a person goes without cancer returning, the better the odds that cancer will not return. Remission is a period of time when cancer is under control, stemming from successful treatment. This may not mean that the cancer has been cured. In complete remission, all indicators of cancer are gone on all tests. In partial remission, the cancer has shrunk but has not vanished.117

  • According to the CDC, cancer is the second leading cause of death behind cardiovascular disease. In 2020, there were 602,350 cancer deaths in the U.S. The good news is that the U.S. cancer rate has dropped 27% between 2001 and 2020.118

  • Parents cannot directly pass cancer to children. Also, the genetic changes that occur in tumors cannot be passed on to the next generation. But genetic changes that increase cancer risks can be inherited by children if those genetic changes are carried by a parent’s sperm or egg cells.119

  • Cancer isn't new. The first written descriptors date back to 3000 B.C. in Egypt. Records discussed eight cases of breast tumors or ulcers that were removed, indicating no treatment existed.120

  • When cancer reaches parts of the body that are far from where it began, it’s called metastatic cancer. For certain types of cancer, this is also called stage IV cancer. Doctors can identify metastatic cancer by examining cells under a microscope. Cells in the new location will be similar to the cancer cells in their original location. Metastatic cancers are named according to their origin points. For example, colon cancer that spreads to the liver is metastatic colon cancer. Sometimes, a metastatic cancer’s origin can’t be pinpointed. This is referred to as cancer of unknown primary origin.121

Find a Pfizer clinical trial for cancer at

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Area of Focus: Oncology

Cancer is a focus of Pfizer’s Oncology Therapeutic Area. Visit the Oncology Page.

The information contained on this page is provided for your general information only. It is not intended as a substitute for seeking medical advice from a healthcare provider. Pfizer is not in the business of providing medical advice and does not engage in the practice of medicine. Pfizer under no circumstances recommends particular treatments for specific individuals and in all cases recommends consulting a physician or healthcare center before pursuing any course of treatment.