Increased risk of breast cancer development after diagnosis of salivary gland tumour.

The aim of this study was to evaluate whether patients with salivary gland tumours are at increased risk of developing breast cancer. A retrospective cohort study was performed. Female patients (n = 439) with a salivary gland tumour (major and minor) were included. The diagnosis was confirmed histologically. The median follow-up was 5.4 years. Fifteen patients out of 439 with a salivary gland tumour subsequently developed breast cancer, with a mean time interval of 64 months. On the basis of incidence rates in the general population 5.93 breast cancers would be expected. The standardised incidence ratio (SIR) was 2.5 (95% confidence interval: 1.4-4.2; P = 0.003). Increased SIRs were also observed for other solid malignancies, but the numbers were small (n < 5). It is concluded that female patients with a salivary gland tumour have a 2.5 times increased risk of developing breast cancer. Breast screening of these patients is therefore recommended.