The Common Cancers

TL;DR. Five cancers account for roughly half of all cases worldwide: lung, breast, colorectal, prostate, and stomach. They differ in cause, in how early they announce themselves, in whether screening helps, and in survival, and the differences are more instructive than the similarities. Lung cancer is mostly one preventable exposure. Cervical cancer is mostly one preventable infection. Colorectal cancer has a precancerous stage that can be removed during the test that finds it. Pancreatic cancer has none of these advantages and remains close to where it was fifty years ago. This chapter is the field guide: what each one is, who gets it, how it shows up, whether screening is worth it, and what the outlook is.

Key takeaways

• Lung cancer is the most diagnosed cancer worldwide (about 12.4 percent of all cases) and the leading cause of cancer death. Most of it is tobacco.
• Breast cancer is the most common cancer in women (11.6 percent of all cases) and now has among the best survival in high-income countries, and among the worst in low-income ones. The gap is about access, not biology.
• Colorectal cancer (9.6 percent) is the clearest screening success: removing polyps prevents the cancer rather than just catching it early.
• Cervical cancer is the only common cancer that is, in principle, eliminable, through HPV vaccination plus screening.
• Pancreatic cancer remains lethal, with five-year survival still around 10 to 13 percent, because it is silent until it has spread.
• Survival figures in this chapter describe populations diagnosed years ago and vary enormously by stage at diagnosis. They are not predictions for individuals.

The global picture

Lung cancer

In short: The most diagnosed cancer and the leading cause of cancer death, mostly tobacco, with CT screening proven to reduce mortality in heavy smokers.

What it is. Two broad groups: non-small cell lung cancer (about 85 percent, including adenocarcinoma and squamous cell carcinoma) and small cell lung cancer (about 15 percent, faster growing, usually spread at diagnosis, initially very chemotherapy-sensitive).

Cause. Tobacco smoking accounts for the large majority; the risk rises with duration more steeply than with intensity, so starting young and smoking for decades is worse than smoking more per day for fewer years. Other causes: radon gas (the leading cause in never-smokers in many countries, and testable in homes cheaply), asbestos, outdoor air pollution, indoor cooking smoke, and secondhand smoke. Lung cancer in never-smokers, particularly adenocarcinoma in women in East Asia, is a distinct and growing entity driven more by inherited driver mutations such as EGFR.

Symptoms. Persistent cough, coughing blood, breathlessness, chest pain, weight loss, recurrent chest infections. All of these appear late, which is the central problem.

Screening. Annual low-dose CT in people with heavy smoking histories reduced lung cancer mortality by about 20 percent in the US NLST trial and about 24 percent in men in the Dutch-Belgian NELSON trial. It is now recommended in several countries. Costs include false positives leading to further scans and biopsies, and overdiagnosis.

Prognosis. Poor overall (roughly 20 to 25 percent five-year survival across all stages in high-income countries) and transformed at the extremes: localised disease resected surgically does well, while targeted therapy and immunotherapy have extended survival in advanced disease from months to years in genetically selected patients.

Breast cancer

In short: One name for at least four diseases, separated by hormone receptor and HER2 status, with survival above 90 percent where treatment is available.

What it is. Cancer of the milk ducts (most) or lobules. Its defining feature today is molecular subtype, which determines treatment more than stage does:

Cause and risk. Age, female sex (men account for under 1 percent of cases), early menarche and late menopause, later or no childbirth, hormone therapy, alcohol, obesity after menopause, physical inactivity, dense breast tissue, family history, and inherited BRCA1/BRCA2 or other high-risk variants (5 to 10 percent of cases).

Symptoms. A new lump, skin dimpling, nipple retraction or discharge, or changes in breast contour. Most lumps are benign, and pain is not a typical feature of cancer.

Screening. Mammography in women roughly 50 to 70 (with variation by country) reduces breast cancer mortality by around 20 percent. The trade-offs are real and worth knowing: false positives, and overdiagnosis of cancers that would never have caused harm, estimated at roughly 10 to 20 percent of screen-detected cancers depending on method. Countries have made different, defensible decisions about start age and interval on the basis of the same data.

Prognosis. Five-year survival exceeds 90 percent in high-income countries and falls below 50 percent in several low-income ones, almost entirely because of late presentation and treatment access.

Colorectal cancer

In short: The best screening target in medicine, because the precancerous polyp can be removed during the same test that finds it.

What it is. Cancer of the colon or rectum, in most cases developing over 10 to 15 years from a benign adenomatous polyp. That long precancerous window is what makes it the best target for screening in medicine.

Cause and risk. Age, processed meat (classified as a group 1 carcinogen by IARC) and high red meat intake, low fibre, obesity, physical inactivity, smoking, alcohol, inflammatory bowel disease, family history, and inherited syndromes (Lynch syndrome, familial adenomatous polyposis). Incidence in adults under 50 has been rising in many countries since the 1990s, for reasons not yet established.

Symptoms. Change in bowel habit, blood in stool, iron deficiency anaemia, abdominal pain, unexplained weight loss.

Screening. Several options, all effective: faecal immunochemical test (FIT) annually or biennially, colonoscopy every ten years, or CT colonography. Colonoscopy is unique in this book: it both detects and prevents, because polyps are removed during the same procedure. Most guidelines now begin at 45.

Prognosis. Five-year survival is roughly 90 percent for localised disease and under 20 percent once distant metastases are present, which makes the case for screening about as clearly as it can be made.

Prostate cancer

In short: Extremely common, frequently harmless, and the reason active surveillance replaced immediate treatment for low-risk disease.

What it is. Cancer of the prostate gland. Its defining problem is heterogeneity: many prostate cancers grow so slowly that they never threaten the man's life, while others metastasise to bone and kill.

Cause and risk. Age (very common in older men; autopsy studies find prostate cancer in a large fraction of men who died of something else), African ancestry (higher incidence and mortality), family history, and BRCA2 mutations.

Symptoms. Usually none until advanced. Urinary symptoms are more commonly caused by benign enlargement.

Screening. The PSA blood test is the most contested screening test in medicine. It reduces prostate cancer mortality modestly and detects a great many cancers that would never have caused harm. The response has been not to abandon testing but to change what follows it: MRI before biopsy, and active surveillance (monitoring low-risk cancers with repeat PSA, MRI, and biopsy, treating only if it progresses) rather than immediate surgery or radiation. That change has substantially reduced the harm of overdiagnosis without giving up the benefit.

Prognosis. Excellent for localised disease (five-year survival near 100 percent), and metastatic disease is now managed for years with hormonal and newer agents.

Skin cancer

In short: Melanoma is uncommon and dangerous, the others common and rarely fatal, and a change in a mole matters more than its appearance.

Melanoma arises from pigment cells. It is far less common than other skin cancers and causes most skin cancer deaths, because it metastasises readily. Risk: UV exposure, particularly intermittent intense exposure and sunburns, fair skin, many moles, family history, and sunbed use. The ABCDE warning signs are Asymmetry, irregular Border, varied Colour, Diameter over 6 mm, and Evolution (change over time), of which change is the most important. Caught early it is cured by excision, with five-year survival above 95 percent for thin lesions. Metastatic melanoma was almost uniformly fatal until checkpoint immunotherapy, which now produces long-term survival in a substantial minority.

Basal cell and squamous cell carcinoma are far more common, driven by cumulative sun exposure, and rarely fatal. Basal cell carcinoma almost never metastasises but destroys local tissue if neglected.

People with darker skin get less skin cancer overall, and are diagnosed later and do worse when they do, partly because it is not looked for and partly because it appears in less sun-exposed sites such as palms, soles, and nail beds (acral melanoma).

Stomach and oesophageal cancer

Stomach cancer has fallen dramatically worldwide, largely because of refrigeration replacing salt preservation and because Helicobacter pylori infection has declined. It remains common in East Asia, where Japan and South Korea run national endoscopic screening programmes that shift diagnosis to early, curable stages. Risk: H. pylori (the dominant cause), salt-preserved foods, smoking, and family history.

Oesophageal cancer comes in two forms with different causes. Squamous cell carcinoma, dominant in East Asia, East Africa, and parts of South America, is driven by smoking, alcohol, and very hot beverages. Adenocarcinoma, dominant in Western countries and rising, arises from chronic acid reflux causing Barrett's oesophagus, and tracks obesity. Both have poor survival because they present late.

Liver cancer

Mostly hepatocellular carcinoma, arising in a liver already scarred by cirrhosis. The dominant causes globally are chronic hepatitis B and hepatitis C, followed by alcohol and, increasingly, metabolic fatty liver disease. In parts of sub-Saharan Africa and Asia, aflatoxin contamination of stored grain and nuts adds to the burden.

It is one of the most preventable major cancers: hepatitis B vaccination at birth, hepatitis C cure, alcohol reduction, and grain storage improvements each remove a cause. Taiwan's universal infant hepatitis B vaccination programme, begun in 1984, produced a measurable fall in childhood liver cancer within two decades, the first demonstration that a vaccine prevents a human cancer.

Prognosis is poor unless found early through surveillance of people with known cirrhosis.

Cervical cancer

In short: Caused by a virus, preventable by both a vaccine and screening, and still killing over 300,000 women a year.

Caused by persistent infection with high-risk human papillomavirus, principally types 16 and 18. HPV is extremely common and usually cleared by the immune system; persistent infection over years causes precancerous changes and then cancer.

This makes cervical cancer the one common cancer with two independent prevention routes. Vaccination of adolescents before exposure prevents the infection: population data from several countries show sharp falls in precancer and, in the earliest-vaccinated cohorts, in cancer itself. Screening, now usually by HPV testing rather than the traditional Pap smear, detects treatable precancerous change years before cancer.

The result is one of medicine's starkest inequities. Cervical cancer is uncommon in countries with vaccination and screening programmes and remains a leading cause of cancer death in women in sub-Saharan Africa, South Asia, and parts of Latin America. It kills over 300,000 women a year, most of them in their productive and childrearing years, and the tools to prevent nearly all of it exist and are cheap.

Pancreatic cancer

The hardest cancer in this chapter. The pancreas sits deep in the abdomen, tumours produce no early symptoms, and the disease is usually advanced when jaundice, back pain, weight loss, or new-onset diabetes in an older adult finally reveals it. KRAS is mutated in around 90 percent of cases and has been essentially undruggable until recently.

Risk: smoking, obesity, chronic pancreatitis, diabetes, family history, and inherited BRCA2 and Lynch syndrome. Five-year survival remains around 10 to 13 percent, up from about 3 percent in the 1970s. No effective general-population screening exists.

Blood cancers

In short: Childhood leukaemia went from under 10 percent survival to around 90, and chronic myeloid leukaemia became a daily tablet.

Leukaemias arise in the bone marrow, crowding out normal blood production, so patients present with anaemia, infection, and bleeding.

• Acute lymphoblastic leukaemia (ALL) is the commonest childhood cancer, and one of oncology's great successes: five-year survival rose from under 10 percent in the 1960s to around 90 percent today with multi-agent chemotherapy protocols.
• Acute myeloid leukaemia (AML) mainly affects older adults and remains hard to cure.
• Chronic myeloid leukaemia (CML) is driven by a single fusion gene, BCR-ABL, and is the model case for targeted therapy, described in Chapter 26.
• Chronic lymphocytic leukaemia (CLL) is often indolent and may need no treatment for years.

Lymphomas arise in lymph nodes and lymphatic tissue, presenting with painless swollen nodes, night sweats, fever, and weight loss. Hodgkin lymphoma is highly curable, with five-year survival around 90 percent, and much of modern survivorship medicine came from learning to reduce the late effects of curing young people. Non-Hodgkin lymphomas are a large family ranging from indolent to rapidly fatal.

Multiple myeloma is a cancer of antibody-producing plasma cells, causing bone destruction, kidney failure, anaemia, and high calcium. It remains incurable and has become far more treatable, with median survival extending from roughly 3 years to well beyond 5 with modern combinations.

Brain and nervous system tumours

Glioblastoma is the commonest malignant primary brain tumour in adults and among the most lethal, with median survival around 15 months even with surgery, radiation, and chemotherapy. Its infiltrating growth makes complete removal impossible, and the blood-brain barrier blocks many drugs.

Meningiomas, arising from the membranes covering the brain, are usually benign and often curable by surgery.

Brain metastases from lung, breast, melanoma, and kidney cancer are far more common than primary brain tumours.

Childhood cancers

Childhood cancer is rare (roughly 400,000 cases a year worldwide) and biologically different: mostly leukaemias, brain tumours, lymphomas, and embryonal tumours such as neuroblastoma, Wilms tumour, and retinoblastoma, rather than the carcinomas of adult life. Children have not lived long enough to accumulate the mutations that cause adult cancers, so childhood cancers typically arise from a small number of developmental errors.

Survival in high-income countries now exceeds 80 percent overall, and is under 30 percent in many low-income countries, an access gap the WHO Global Initiative for Childhood Cancer is aimed at. The other consequence of success is survivorship: adults cured as children carry lifelong risks from the treatment itself, including second cancers, heart damage, infertility, and cognitive effects, which is why paediatric protocols now deliberately de-escalate treatment where they can.

Sources and notes

Incidence shares and the 2022 counts are from GLOBOCAN 2022 (Bray et al., 2024). Lung cancer screening: NLST (NEJM, 2011) and NELSON (NEJM, 2020). Breast screening effect sizes and overdiagnosis estimates: the Independent UK Panel on Breast Cancer Screening (The Lancet, 2012) and subsequent analyses; estimates vary by method and remain debated. Colorectal survival by stage and screening modality effectiveness: national cancer registry data and USPSTF evidence reviews. Prostate screening: ERSPC and PLCO trials, and subsequent active surveillance cohorts (ProtecT, NEJM, 2016 and 2023 follow-up). Hepatitis B vaccination and childhood liver cancer in Taiwan: Chang et al., NEJM, 1997. HPV vaccination effect on cervical cancer: Lei et al., NEJM, 2020 (Sweden) and Falcaro et al., The Lancet, 2021 (England). Childhood cancer survival disparities: WHO Global Initiative for Childhood Cancer. Survival percentages are five-year relative survival from high-income registries unless stated, and are historical by construction.

Open questions. The cause of rising early-onset colorectal cancer is unknown. The net benefit of mammography and PSA screening continues to be argued by serious people on both sides. Whether multi-cancer early detection blood tests will help or mostly generate overdiagnosis is the field's largest open empirical question.

Next: what is actually done about all of this, and how each treatment works. 👉