Basal cell skin cancer and the risk of second primary cancers: a cancer registry–based study in Lithuania

• Our study provides the population-based evaluation of second primary cancer risk in BCC patients.
• We found an increased cancer risk for cancers related to sun exposure—melanoma and lip cancer.
• Increased risks were identified for the HL, thyroid cancer, leukemia, prostate, and breast cancer.
• Significant decrease in risk of any second primary cancer after BCC was not determined.

PurposeThe aim of this population-based cohort study was to determine the risk of second primary cancer in basal cell carcinoma (BCC) patients in Lithuania.MethodsThis analysis was based on patients diagnosed with BCC in Lithuania between 1998 and 2007 and followed until 2011. Standardized incidence ratios for subsequent cancers as a ratio of observed number of cancer cases in people with previous BCC diagnosis to the expected number of cancer cases in the underlying general population were calculated.ResultsAfter diagnosis of BCC, 1442 new cases of selected cancers were diagnosed. Compared with the general population, the incidence of all new primaries combined after BCC was very close to expected. Statistically meaningful increase in developing subsequent cancer was obtained for Hodgkin's lymphoma, prostate cancer, and leukemia in men, and for cancers of the lip, lung, and breast in women. Risk of melanoma and thyroid cancer was significantly elevated in both sexes. Relative risk of cancer of the eye was increased although not significant.ConclusionsIn our study, we found increased cancer risk for cancers related to sun exposure. In addition, increased risks were identified for Hodgkin's lymphoma, thyroid cancer, leukemia, prostate, and breast cancer in BCC patients.