Second primary cancer after major salivary gland carcinoma.

BACKGROUND: We investigated the risk of second primary cancers after major salivary gland carcinoma in Finland, with a population of 5.5 million. METHODS: Nationwide cancer registry data were used to identify patients with major salivary gland carcinoma diagnosed between 1953 and 2014. Standardized incidence ratios (SIRs) were estimated to compare their second primary cancer risk with the respective site-specific cancer risk in the general population. RESULTS: There were 1727 patients with major salivary gland carcinomas and 222 second primary cancers had been diagnosed in these patients (SIR 1.43). The risk was increased for cancers of the thyroid (SIR 5.12), breast (SIR 1.63), respiratory organs (SIR 1.63), male genital organs (SIR 1.48), melanoma of the skin (SIR 3.35), and nonmelanoma skin cancer (SIR 2.50). The risk was high during the first 5 years and after 20 years of diagnosis. CONCLUSION: Second primary cancers can occur among patients with major salivary gland carcinoma even after a long time period. This needs to be recognized in the follow-up of these patients.