Rising incidence of breast cancer among female cancer survivors: implications for surveillance

The number of female cancer survivors has been rising rapidly. We assessed the occurrence of breast cancer in these survivors over time. We computed incidence of primary breast cancer in two cohorts of female cancer survivors with a first diagnosis of cancer at ages 30+ in the periods 1975-1979 and 1990-1994. Cohorts were followed for 10 years through a population-based cancer registry. Over a period of 15 years, the incidence rate of breast cancer among female cancer survivors increased by 30%(age standardised rate ratio (RR-adj): 1.30; 95% CI: 1.03-1.68). The increase was significant for non-breast cancer survivors (RR-adj: 1.41, 95% CI: 1.04-2.75). During the study period, the rate of second breast cancer stage II tripled (RR-adj: 3.10, 95% CI: 1.73-5.78). Non-breast cancer survivors had a significantly (P value = 0.005) more unfavourable stage distribution ( 62% stage II and III) than breast cancer survivors (32% stage II and III). A marked rise in breast cancer incidence among female cancer survivors was observed. Research to optimise follow-up strategies for these women to detect breast cancer at an early stage is warranted.