SynonymsMalignant tumor, malignant neoplasm
Tumor Mesothelioma2 legend.jpg
A coronal CT scan showing a malignant mesothelioma
Legend: → tumor ←, ✱ central pleural effusion, 1 & 3 lungs, 2 spine, 4 ribs, 5 aorta, 6 spleen, 7 & 8 kidneys, 9 liver
SymptomsLump, abnormal bleeding, prolonged cough, unexplained weight loss, change in bowel movements[1]
Risk factorsTobacco, obesity, poor diet, lack of physical activity, excessive alcohol, certain infections[2][3]
TreatmentRadiation therapy, surgery, chemotherapy, and targeted therapy.[2][4]
PrognosisAverage five year survival 66% (USA)[5]
Frequency90.5 million (2015)[6]
Deaths8.8 million (2015)[7]

Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body.[2][8] These contrast with benign tumors, which do not spread.[8] Possible signs and symptoms include a lump, abnormal bleeding, prolonged cough, unexplained weight loss and a change in bowel movements.[1] While these symptoms may indicate cancer, they can also have other causes.[1] Over 100 types of cancers affect humans.[8]

Tobacco use is the cause of about 22% of cancer deaths.[2] Another 10% are due to obesity, poor diet, lack of physical activity or excessive drinking of alcohol.[2][9][10] Other factors include certain infections, exposure to ionizing radiation and environmental pollutants.[3] In the developing world, 15% of cancers are due to infections such as Helicobacter pylori, hepatitis B, hepatitis C, human papillomavirus infection, Epstein–Barr virus and human immunodeficiency virus (HIV).[2] These factors act, at least partly, by changing the genes of a cell.[11] Typically, many genetic changes are required before cancer develops.[11] Approximately 5–10% of cancers are due to inherited genetic defects from a person's parents.[12] Cancer can be detected by certain signs and symptoms or screening tests.[2] It is then typically further investigated by medical imaging and confirmed by biopsy.[13]

Many cancers can be prevented by not smoking, maintaining a healthy weight, not drinking too much alcohol, eating plenty of vegetables, fruits and whole grains, vaccination against certain infectious diseases, not eating too much processed and red meat and avoiding too much sunlight exposure.[14][15] Early detection through screening is useful for cervical and colorectal cancer.[16] The benefits of screening in breast cancer are controversial.[16][17] Cancer is often treated with some combination of radiation therapy, surgery, chemotherapy and targeted therapy.[2][4] Pain and symptom management are an important part of care.[2] Palliative care is particularly important in people with advanced disease.[2] The chance of survival depends on the type of cancer and extent of disease at the start of treatment.[11] In children under 15 at diagnosis, the five-year survival rate in the developed world is on average 80%.[18] For cancer in the United States, the average five-year survival rate is 66%.[5]

In 2015, about 90.5 million people had cancer.[6] About 14.1 million new cases occur a year (not including skin cancer other than melanoma).[11] It caused about 8.8 million deaths (15.7% of deaths).[7] The most common types of cancer in males are lung cancer, prostate cancer, colorectal cancer and stomach cancer.[19] In females, the most common types are breast cancer, colorectal cancer, lung cancer and cervical cancer.[11] If skin cancer other than melanoma were included in total new cancer cases each year, it would account for around 40% of cases.[20][21] In children, acute lymphoblastic leukemia and brain tumors are most common, except in Africa where non-Hodgkin lymphoma occurs more often.[18] In 2012, about 165,000 children under 15 years of age were diagnosed with cancer.[19] The risk of cancer increases significantly with age, and many cancers occur more commonly in developed countries.[11] Rates are increasing as more people live to an old age and as lifestyle changes occur in the developing world.[22] The financial costs of cancer were estimated at $1.16 trillion USD per year as of 2010.[23]


Cancers are a large family of diseases that involve abnormal cell growth with the potential to invade or spread to other parts of the body.[2][8] They form a subset of neoplasms. A neoplasm or tumor is a group of cells that have undergone unregulated growth and will often form a mass or lump, but may be distributed diffusely.[24][25]

All tumor cells show the six hallmarks of cancer. These characteristics are required to produce a malignant tumor. They include:[26]

The progression from normal cells to cells that can form a detectable mass to outright cancer involves multiple steps known as malignant progression.[26][27]

Other Languages
Afrikaans: Kanker
Alemannisch: Krebs (Medizin)
አማርኛ: ካንሰር
العربية: سرطان
aragonés: Cáncer
ܐܪܡܝܐ: ܬܠܗܝܐ
অসমীয়া: কৰ্কট ৰোগ
asturianu: Cáncanu
Avañe'ẽ: Akytã'ai
azərbaycanca: Xərçəng xəstəliyi
تۆرکجه: سرطان
Bân-lâm-gú: Gâm
башҡортса: Яман шеш
беларуская (тарашкевіца)‎: Рак (захворваньне)
भोजपुरी: कैंसर
български: Рак (болест)
བོད་ཡིག: འབྲས་སྐྲན།
bosanski: Rak (bolest)
brezhoneg: Krign-bev
català: Càncer
čeština: Rakovina
Cymraeg: Canser
dansk: Kræft
davvisámegiella: Boras
ދިވެހިބަސް: ކެންސަރު
डोटेली: कर्कट रोग
Ελληνικά: Καρκίνος
español: Cáncer
Esperanto: Kancero
estremeñu: Cancru
euskara: Minbizi
فارسی: سرطان
Fiji Hindi: Cancer
français: Cancer
Frysk: Kanker
Gaeilge: Ailse
Gaelg: Kahngyr
Gàidhlig: Aillse
galego: Cancro
客家語/Hak-kâ-ngî: Ngàm
Hausa: Sankara
հայերեն: Քաղցկեղ
हिन्दी: कर्कट रोग
hrvatski: Rak (bolest)
Ido: Kancero
Ilokano: Kanser
Bahasa Indonesia: Kanker
interlingua: Cancere
íslenska: Krabbamein
Basa Jawa: Kanker
Kapampangan: Cancer
ქართული: სიმსივნე
қазақша: Қатерлі ісік
Kiswahili: Saratani
Kreyòl ayisyen: Kansè
kurdî: Şêrpence
lietuvių: Vėžys (liga)
Limburgs: Kaanker
Luganda: Kokolo
македонски: Рак (болест)
മലയാളം: അർബുദം
मराठी: कर्करोग
მარგალური: კიბო
مصرى: سرطان
Bahasa Melayu: Barah
Mìng-dĕ̤ng-ngṳ̄: Ngàng
монгол: Хорт хавдар
မြန်မာဘာသာ: ကင်ဆာရောဂါ
Nederlands: Kanker
Nedersaksies: Kaanker
नेपाली: क्यान्सर
नेपाल भाषा: क्यान्सर
日本語: 悪性腫瘍
Nordfriisk: Kreeft
norsk: Kreft
norsk nynorsk: Kreft
occitan: Càncer
ଓଡ଼ିଆ: କର୍କଟ ରୋଗ
oʻzbekcha/ўзбекча: Saraton (kasallik)
پنجابی: سرطان
پښتو: سرطان
Patois: Kiansa
Tok Pisin: Kensa
português: Câncer
română: Cancer
Runa Simi: Apanqara unquy
русиньскый: Раковіна
संस्कृतम्: कर्कटरोगः
Scots: Cancer
shqip: Kanceri
සිංහල: පිළිකා
Simple English: Cancer
سنڌي: ڪينسر
slovenčina: Zhubný nádor
slovenščina: Rak (bolezen)
Soomaaliga: Kansar
کوردی: شێرپەنجە
српски / srpski: Рак (болест)
srpskohrvatski / српскохрватски: Kancer
Basa Sunda: Kangker
suomi: Syöpä
svenska: Cancer
Tagalog: Kanser
татарча/tatarça: Яман шеш
తెలుగు: కాన్సర్
Türkçe: Kanser
українська: Злоякісна пухлина
Vahcuengh: Bingh'aizcwng
vèneto: Càncaro
Tiếng Việt: Ung thư
Võro: Vähktõbi
Winaray: Kanser
Xitsonga: Fukuzana
ייִדיש: קענסער
Zazaki: Qanser
žemaitėška: Viežīs (lėga)
中文: 癌症