Cancer

Cancer is a group of <a href="/facts/Disease/55eeQlGL">diseases</a> involving <a href="/facts/Cell_growth/wbArMaJU">abnormal cell growth</a> with the potential to <a href="/facts/Invasion_(cancer)/rcVXSgzg">invade</a> or <a href="/facts/Metastasis/4dadbm6z">spread</a> to other parts of the body. These contrast with <a href="/facts/Benign_tumor/ssJPkY84">benign tumors</a>, which do not spread. Possible <a href="/facts/Signs_and_symptoms_of_cancer/PQnHFQs2">signs and symptoms</a> include a lump, abnormal bleeding, prolonged cough, unexplained weight loss, and a change in <a href="/facts/Defecation/EBv8o15S">bowel movements</a>. While these symptoms may indicate cancer, they can also have other causes. <a href="/facts/List_of_cancer_types/gKyTPP2x">Over 100 types</a> of cancers affect humans.
<a href="/facts/Tobacco_use/obI4MYne">Tobacco use</a> is the cause of about 22% of cancer deaths. Another 10% are due to <a href="/facts/Obesity/RBF9y5Vl">obesity</a>, poor <a href="/facts/Diet_(nutrition)/7qzDHpop">diet</a>, <a href="/facts/Sedentary_lifestyle/17LNyhNV">lack of physical activity</a> or <a href="/facts/Alcohol_abuse/PNlrAG7j">excessive alcohol consumption</a>. Other factors include certain infections, exposure to <a href="/facts/Ionizing_radiation/vw0d9GaT">ionizing radiation</a>, and environmental pollutants. <a href="/facts/Infectious_causes_of_cancer/GvjlQbh1">Infection</a> with specific viruses, bacteria and parasites is an environmental factor causing approximately 16–18% of cancers worldwide. These infectious agents include <a href="/facts/Helicobacter_pylori/9q4H68LP">Helicobacter pylori</a>, <a href="/facts/Hepatitis_B_virus/vk2qncf2">hepatitis B</a>, <a href="/facts/Hepatitis_C_virus/DFUwAzlB">hepatitis C</a>, <a href="/facts/Human_papillomavirus_infection/7XW8mjG2">HPV</a>, <a href="/facts/Epstein%25E2%2580%2593Barr_virus/Uv8f1PNd">Epstein–Barr virus</a>, <a href="/facts/Human_T-lymphotropic_virus_1/ups6exft">Human T-lymphotropic virus 1</a>, <a href="/facts/Kaposi%2527s_sarcoma-associated_herpesvirus/uP1fKRnI">Kaposi's sarcoma-associated herpesvirus</a> and <a href="/facts/Merkel_cell_polyomavirus/E70Kkmd8">Merkel cell polyomavirus</a>. <a href="/facts/HIV/ulY2rgzu">Human immunodeficiency virus</a> (HIV) does not directly cause cancer but it causes immune deficiency that can magnify the risk due to other infections, sometimes up to several thousandfold (in the case of <a href="/facts/Kaposi%2527s_sarcoma/0IFdzpbH">Kaposi's sarcoma</a>). Importantly, vaccination against the <a href="/facts/Hepatitis_B_virus/vk2qncf2">hepatitis B virus</a> and the <a href="/facts/Human_papillomavirus/7XW8mjG2">human papillomavirus</a> have been shown to nearly eliminate the risk of cancers caused by these viruses in persons successfully vaccinated prior to infection.
These environmental factors act, at least partly, by changing the <a href="/facts/Gene/e1swwPY6">genes</a> of a cell. Typically, many genetic changes are required before cancer develops. Approximately 5–10% of cancers are due to inherited genetic defects. Cancer can be detected by certain signs and symptoms or screening tests. It is then typically further investigated by <a href="/facts/Medical_imaging/pL6JyJEp">medical imaging</a> and confirmed by <a href="/facts/Biopsy/A0TdRRlr">biopsy</a>.
The risk of developing certain cancers can be reduced by not smoking, maintaining a healthy weight, limiting alcohol intake, eating plenty of vegetables, fruits, and <a href="/facts/Whole_grain/arLz8FWD">whole grains</a>, <a href="/facts/Vaccination/3SfpzPsd">vaccination</a> against certain infectious diseases, limiting consumption of <a href="/facts/Processed_meat/LvyBpwac">processed meat</a> and <a href="/facts/Red_meat/LemELNcF">red meat</a>, and limiting exposure to direct sunlight. Early detection through screening is useful for <a href="/facts/Cervical_cancer/99vngUyd">cervical</a> and <a href="/facts/Colorectal_cancer/nV592sW7">colorectal cancer</a>. The benefits of <a href="/facts/Breast_cancer_screening/YDmYjJfR">screening for breast cancer</a> are controversial. Cancer is often treated with some combination of <a href="/facts/Radiation_therapy/j60q5EC6">radiation therapy</a>, surgery, <a href="/facts/Chemotherapy/fWTLbaUT">chemotherapy</a> and <a href="/facts/Targeted_therapy/QaHGLjc6">targeted therapy</a>. More <a href="/facts/Personalized_medicine/rawUyWgd">personalized therapies</a> that harness a patient's immune system are emerging in the field of <a href="/facts/Cancer_immunotherapy/0QKPeh5x">cancer immunotherapy</a>. Pain and symptom management are an important part of care. <a href="/facts/Palliative_care/06oIFgon">Palliative care</a> is particularly important in people with advanced disease. The chance of survival depends on the type of cancer and <a href="/facts/Cancer_staging/d2cFsCtq">extent of disease</a> at the start of treatment. In children under 15 at diagnosis, the <a href="/facts/Five-year_survival_rate/C6PENRfq">five-year survival rate</a> in the <a href="/facts/Developed_world/sqwTSDHm">developed world</a> is on average 80%. For cancer in the United States, the average five-year survival rate is 66% for all ages.
In 2015, about 90.5 million people worldwide had cancer. In 2019, annual cancer cases grew by 23.6 million people, and there were 10 million deaths worldwide, representing over the previous decade increases of 26% and 21%, respectively.
The most common types of cancer in males are <a href="/facts/Lung_cancer/LHLdR454">lung cancer</a>, <a href="/facts/Prostate_cancer/Mx7XuDhm">prostate cancer</a>, <a href="/facts/Colorectal_cancer/nV592sW7">colorectal cancer</a>, and <a href="/facts/Stomach_cancer/HJjYtkqS">stomach cancer</a>. In females, the most common types are <a href="/facts/Breast_cancer/6hME580v">breast cancer</a>, colorectal cancer, lung cancer, and <a href="/facts/Cervical_cancer/99vngUyd">cervical cancer</a>. If <a href="/facts/Skin_cancer/r9BWEX7W">skin cancer</a> other than <a href="/facts/Melanoma/qdT7E97Y">melanoma</a> were included in total new cancer cases each year, it would account for around 40% of cases. In children, <a href="/facts/Acute_lymphoblastic_leukemia/vRIAjkRJ">acute lymphoblastic leukemia</a> and <a href="/facts/Brain_tumor/avjI5Nhm">brain tumors</a> are most common, except in Africa, where <a href="/facts/Non-Hodgkin_lymphoma/KIFxt74F">non-Hodgkin lymphoma</a> occurs more often. In 2012, about 165,000 children under 15 years of age were diagnosed with cancer. The risk of cancer increases significantly with age, and many cancers occur more commonly in developed countries. Rates are increasing as <a href="/facts/Population_ageing/s71KXvey">more people live to an old age</a> and as lifestyle changes occur in the developing world. The global total economic costs of cancer were estimated at <a href="/facts/United_States_dollar/naEEDUhC">US$</a>1.16 trillion (equivalent to $1.67 trillion in 2024) per year as of 2010.

Cancer open-in-new

Cancer