Standard Screening — The Big Four
Four tests prevent or catch most screenable cancers
Among cancers with proven screening benefit (colorectal, breast, cervical, prostate ± lung), the right tests performed at the right intervals save tens of thousands of lives per year in the US alone. Most countries have national programmes. Most individuals still skip or delay them.
Colonoscopy — the gold standard
USPSTF recommends colonoscopy starting at 45 (updated from 50 in 2021), repeat every 10 years if normal. Catches polyps before they become cancer, and colorectal cancer caught early is highly curable. Alternatives include FIT (annual stool test) or Cologuard (every 3 years) — less sensitive but less invasive.
Mammogram — overdiagnosis vs underdiagnosis
USPSTF 2024: biennial mammograms 40–74 for average-risk women (lowered from 50 in 2024 update). Dense breast tissue often benefits from supplemental ultrasound or MRI. The "overdiagnosis" debate is real — some detected cancers wouldn't progress — but the mortality-reduction signal is also real.
Pap + HPV, PSA, low-dose CT
Cervical: Pap every 3 years OR HPV co-test every 5 years, 21–65. Prostate: PSA after 45–50 with shared decision-making; modern practice uses PSA + free PSA ratio + MRI rather than biopsy-first. Lung: annual low-dose CT for 50–80-year-olds with 20+ pack-year smoking history.
Match the screen to its start age
Connect each screening test to its recommended start age.
Key Takeaway
The big four (+ lung CT if a smoker) catch or prevent most screenable cancers. None requires specialist referrals in most systems. Set reminders at the right ages, use the Screening Calendar tool, and actually book them. Most missed diagnoses come from skipped screening, not from screening that failed.
References
- USPSTF — colorectal cancer screening at 45
- USPSTF 2024 breast cancer screening update