Primary malignancy after primary female breast cancer in the south of the Netherlands, 1972-2001

Objectives. To assess the risk of second primary cancers among women with previous breast cancer and calculate the excess burden of second cancer in the population. Methods. A population-based longitudinal study was conducted using the Eindhoven cancer registry data on 9919 breast cancer patients diagnosed in the period 1972-2000 and followed until 2001. Standardised incidence ratios (SIR) and absolute excess risks (AER) were calculated. Results. In total, 1298 (13%) women developed a second primary cancer. The risk of overall second cancer was higher among breast cancer patients compared to the general population (SIR: 2.8; 95% CI: 2.6-2.9), with an AER of 115 second cancers for every 10,000 breast cancer patients per year. High SIR and AER were observed for breast cancer (SIR: 4.1; 95% CI: 3.8-4.4; AER: 64/10,000 patients/year) and ovarian cancer (SIR: 2.0; 95% CI: 1.5-2.7; AER: 4.5/10,000 patients/year). Conclusions. Our recent data show that women with previous breast cancer have an elevated risk of developing a second cancer compared to the general population. Excess burden for the population is especially high for second cancers of the breast, ovary and colon. Screening may only be justified for breast, ovary and colon cancer in certain groups of patients.