Why this is examined
Canadian screening guidance is set by the Canadian Task Force on Preventive Health Care (CTFPHC) and is consistently less aggressive than the US equivalents. Questions are written so that the American answer is available and wrong.
Cancer screening
| Cancer | Who | Test and interval |
|---|---|---|
| Cervical | Started at 25 (some provinces 21), to 69 | Cytology every 3 years; HPV-based programmes are replacing this province by province |
| Breast | 50–74 | Mammography every 2–3 years. Screening at 40–49 is an individual decision after discussing benefits and harms |
| Colorectal | 50–74 | FIT every 2 years, or flexible sigmoidoscopy every 10 years. Colonoscopy is not the population screening tool in Canada |
| Lung | 55–74 with ≥ 30 pack-years, smoking now or quit < 15 years | Annual low-dose CT, in an organised programme |
| Prostate | — | PSA screening is not recommended. This is the single most reliable MCCQE screening answer |
Stop cervical screening at 69–70 if screening has been adequate and negative. Screening ends at 74 for breast and colorectal because the evidence does not extend beyond it.
Higher-risk pathways
These sit outside population screening and start earlier:
- First-degree relative with colorectal cancer — colonoscopy from 40, or 10 years before the relative's diagnosis
- Known Lynch syndrome or FAP — dedicated surveillance from adolescence or early adulthood
- BRCA carriers, or chest radiotherapy before 30 — annual MRI plus mammography from 30
- Cirrhosis or chronic hepatitis B — 6-monthly ultrasound for hepatocellular carcinoma
Non-cancer screening worth knowing
- AAA: one-time ultrasound for men aged 65–80
- Diabetes: risk-calculator driven; every 3 years from 40, sooner if risk is high
- Lipids: from 40, or earlier with risk factors
- Blood pressure: at every appropriate clinical encounter
- Osteoporosis: BMD from 65 in both sexes, earlier with risk factors
- Chlamydia and gonorrhoea: sexually active people under 25, and anyone with risk factors
- Depression: not recommended as routine population screening; ask when there are clinical clues
The screening principles behind the answers
When a stem asks whether a programme is worthwhile, the reasoning is Wilson–Jungner:
- The condition must be important and have a detectable latent phase
- The test must be acceptable, sensitive and specific
- Treatment in the latent phase must improve outcomes — the point prostate screening struggles with
- Benefits must outweigh overdiagnosis, false positives and downstream harm
And the biases that make a poor programme look good: lead time (earlier diagnosis, same death date), length time (screening preferentially finds indolent disease), and overdiagnosis (finding disease that would never have mattered).