Cancer

Cancer is a broad term for a group of diseases characterised by the uncontrolled growth and spread of abnormal cells. Normally, cells grow, divide, and die in an orderly way. In cancer, this process breaks down — abnormal cells grow out of control and can invade nearby tissues or spread to other parts of the body through the blood and lymphatic system (a process called metastasis). There are over 100 types of cancer, named after the organ or cell type where they originate. In Nigeria, the most commonly diagnosed cancers include breast cancer, cervical cancer, prostate cancer, colorectal cancer, liver cancer, and lymphoma. Cancer is increasingly a leading cause of death in Nigeria alongside non-communicable diseases, though many cancers are preventable, detectable early, and treatable.

Cancer symptoms vary widely depending on the type and location, but warning signs that should never be ignored include: General warning signs (apply across many cancer types): • Unexplained weight loss of 5 kg or more • Persistent fatigue that does not improve with rest • Unexplained fever recurring over weeks • Night sweats • Persistent pain not explained by injury or other illness • Changes in bowel or bladder habits lasting more than a few weeks Specific warning signs: • A new lump or thickening anywhere in the body (breast, neck, groin, armpit) • A sore or wound that does not heal • Unusual bleeding or discharge — coughing blood, blood in urine or stool, abnormal vaginal bleeding • A mole or skin lesion that changes in size, shape, colour, or bleeds • Difficulty swallowing or persistent indigestion • Persistent hoarseness or cough • Nipple discharge or inversion • Pelvic pain or bleeding after menopause or after sex (cervical/uterine cancer warning signs)

Cancer is caused by mutations (changes) in the DNA of cells that cause abnormal, uncontrolled growth. These mutations can be: Acquired (not inherited): • Carcinogens — substances that damage DNA: – Tobacco smoke (lung, mouth, throat, oesophageal, bladder cancer) – Aflatoxin from mouldy groundnuts and grains (liver cancer — common in Nigeria) – Alcohol (liver, oesophageal, breast, bowel cancer) – Ultraviolet radiation from the sun (skin cancer) – Radiation and some industrial chemicals • Oncogenic infections: – Human papillomavirus (HPV) — causes virtually all cervical cancers and some oropharyngeal cancers – Hepatitis B and C viruses — leading causes of liver cancer in Nigeria – Helicobacter pylori — stomach cancer – Epstein-Barr virus (EBV) — Burkitt lymphoma, common in Nigerian children – HIV — increases risk of several cancers Inherited gene mutations (hereditary cancer): • BRCA1/BRCA2 mutations — hereditary breast and ovarian cancer • Lynch syndrome — hereditary colorectal and endometrial cancer • Inherited mutations account for a minority (5–10%) of all cancers

Modifiable risk factors (lifestyle/environment): • Tobacco smoking and chewing • Excessive alcohol consumption • Overweight and obesity (linked to breast, colon, endometrial, and other cancers) • Physical inactivity • Unhealthy diet — high in processed/red meat, low in fruits and vegetables • Exposure to aflatoxins (eating poorly stored groundnuts, grains, dried fish) • Chronic infection with HPV, Hepatitis B or C, H. pylori • Prolonged exposure to carcinogens at work (asbestos, benzene, pesticides) Non-modifiable risk factors: • Age — cancer risk increases significantly with age • Family history of cancer • Inherited gene mutations (e.g., BRCA1/BRCA2) • Sex — some cancers are sex-specific (prostate, cervical, testicular)

The complications of cancer depend on the type, stage, and location but can include: • Spread (metastasis) to other organs — most commonly bones, liver, lungs, or brain • Organ failure — as tumours grow or spread • Pain — from tumour pressure, nerve involvement, or bone involvement • Severe weight loss and malnutrition (cancer cachexia) • Fatigue and anaemia • Infections — cancer and its treatment weaken the immune system • Blood clots (deep vein thrombosis and pulmonary embolism) — a significant risk in cancer patients • Treatment complications — chemotherapy can cause nausea, hair loss, mouth sores, peripheral neuropathy, bone marrow suppression; radiation can cause burns and damage to surrounding tissue • Psychological impact — depression and anxiety are very common • Death

Up to one-third of all cancers are preventable: Tobacco: • Do not smoke; avoid second-hand smoke • Avoid smokeless tobacco (snuff, chewing tobacco) Diet and weight: • Maintain a healthy weight • Eat a diet rich in fruits, vegetables, and whole grains • Limit red and processed meat • Reduce aflatoxin exposure — buy from reputable sources, store grain and groundnuts properly, discard mouldy food Alcohol: • Limit or avoid alcohol Infection prevention (key in Nigeria): • HPV vaccination for girls and boys aged 9–14 (before sexual activity) — prevents cervical and other HPV-related cancers • Hepatitis B vaccination — prevents hepatitis B-related liver cancer • Use condoms consistently to reduce HPV and HIV transmission Early detection: • Cervical cancer screening (VIA or Pap smear) for women • Breast self-examination monthly • Discuss prostate cancer screening with your doctor at age 50 (or earlier if high-risk) • Do not delay seeing a doctor for persistent warning symptoms