The early diagnosis of breast cancer--a twenty-year experience at the Royal Marsden Hospital.

Over 30,000 women with minimal symptoms were examined between 1968 and 1987 for the detection of early stage breast cancer. Subsequent follow-up screening was selected for women at higher risk because of family history, previous significant benign breast change (e.g. epitheliosis) and hormone replacement therapy. 552 cases of cancer were diagnosed and the current prevalent detection rate is 8.5 per 1000 women examined. Incident cancer (screen-detected and interval) occurred in 6.2 per 1000 women-years at risk. Of the prevalent cancers, 47% were in early T stages of development (TIS, T0 and T1) and this proportion rose to 70% in the screened group. Survival is stage-dependent but the group has not reached its median survival at 15 years. Actuarial estimates of the percentages surviving at 10 years are 73% in the prevalent group and 80% in the incident group.