UK Cancer Screening Programmes

Cervical cancer

•    Age range:

o    25–49 years: every 3 years

o    50–64 years: every 5 years

•    Method: HPV testing as primary screening (detects high-risk HPV types 16, 18)

•    Impact: significant reduction in cervical cancer incidence and mortality

•    Key risk factors:

o    Early sexual activity

o    Multiple partners

o    Smoking

o    Immunosuppression

Breast cancer

•    Age range:

o    50–70 years: every 3 years (with gradual extension 47–73 in some areas)

•    Method: two-view mammography

•    BRCA carriers: annual MRI + mammography from ~30

Colorectal cancer

•    Age range (England):

o    FIT (faecal immunochemical test) every 2 years, 60–74 years

o    Flexible sigmoidoscopy offered once at 55 in some areas

•    FIT: detects occult blood → lower threshold for positivity than gFOBT

•    High-risk groups (e.g., Lynch, FAP): earlier colonoscopy screening

Key Environmental & Lifestyle Risk Factors

Smoking

•    Cancers:

o    Lung (85% of cases)

o    Bladder

o    Oesophageal (squamous)

o    Pancreatic

o    Renal

o    Head and neck (oral cavity, larynx)

o    Cervix

•    Mechanism: polycyclic aromatic hydrocarbons, nitrosamines → DNA adducts

Alcohol

•    Cancers:

o    Oropharyngeal, laryngeal, oesophageal (squamous cell carcinoma)

o    Liver (via cirrhosis)

o    Breast (dose-dependent; risk increases even with 1 drink/day)

o    Colorectal

HPV

•    Cancers:

o    Cervical (>99%)

o    Vulvar, vaginal, penile, anal

o    Oropharyngeal (esp. tonsil and base of tongue)

EBV

•    Cancers:

o    Nasopharyngeal carcinoma (common in SE Asia)

o    Burkitt lymphoma (endemic type)

o    Hodgkin lymphoma (esp. mixed cellularity subtype)

o    Post-transplant lymphoproliferative disorder (PTLD)

Asbestos

•    Cancers:

o    Mesothelioma (pleura > peritoneum)

o    Lung cancer (synergistic with smoking; multiplicative risk)

•    Other risks: asbestosis (interstitial lung disease)

Genetic Cancer Syndromes

BRCA1 and BRCA2 mutations

•    Breast cancer: lifetime risk ~60–85% (BRCA1 slightly higher than BRCA2)

•    Ovarian cancer: ~20–60% risk

•    Other cancers: prostate (esp. BRCA2), pancreatic, male breast cancer

Lynch syndrome (HNPCC)

•    Mutation: mismatch repair genes (MLH1, MSH2, MSH6, PMS2)

•    Colorectal cancer: ~80% lifetime risk, often proximal colon, younger age

•    Endometrial cancer: ~60%

•    Other cancers: ovarian (~12%), gastric, small bowel, upper urinary tract, hepatobiliary, brain (Turcot variant)

Familial Adenomatous Polyposis (FAP)

•    Mutation: APC gene (chromosome 5q)

•    Colorectal cancer: near 100% lifetime risk if untreated

•    Other associated tumours:

o    Duodenal and periampullary cancers

o    Desmoid tumours

o    Papillary thyroid cancer

o    Congenital hypertrophy of the retinal pigment epithelium (CHRPE)

Extra Revision Pearls

•    Screening vs surveillance:

o    Screening: asymptomatic, general population

o    Surveillance: high-risk individuals or post-treatment monitoring

•    Lead-time bias: apparent survival benefit due to earlier detection, not true improvement

•    Length-time bias: screening more likely to detect slower-growing, less aggressive cancers