A mammogram is a low-dose X-ray that shows tumours and the tiny calcium specks early cancer leaves behind. Catch a cancer at stage I and five-year survival is above 98%; catch it at stage III and it drops near 72%. Screening roughly halves the share found late ¹.

Dense breasts are the catch. Gland tissue is bright on the scan just like a tumour, so cancers hide in it. About 40% of women land in the two densest categories ², and in the densest, a standard mammogram misses roughly a third of cancers ³. Dense breasts also carry about twice the baseline risk ³.

3D mammography (tomosynthesis) sees through overlapping tissue: about one extra cancer per thousand scans and 15% fewer false-alarm call-backs ⁴. Take it if your centre offers it. For truly dense breasts, adding MRI cut the aggressive cancers found between scans from 5.0 to 0.8 per thousand ⁵.

High risk needs a different schedule. A known BRCA mutation, chest radiation in youth, or modelled lifetime risk above 20% means annual MRI plus mammography, often starting in your twenties or thirties and alternated so something checks every six months ^{7 8}. If any of that describes you, this is the conversation to have before your next appointment.

Thirty years, in practice. Most visits are a non-event: twenty minutes, brief compression, a normal result a week later. A few times you'll get called back for an extra view that turns out fine. Once, maybe, a radiologist finds a 6-millimetre cluster you couldn't feel — a stage I cancer, a lumpectomy and a few weeks of radiation, back to normal life by summer. Same story without screening starts a year later with a lump in the shower, and it uses more of your life to get through.