The risk of subsequent malignancies in patients with renal cell carcinoma: A nationwide, population-based study

Purpose: The purpose was to investigate the risk of subsequent malignancies in patients with renal cell carcinoma (RCC) using hospital-based cancer registry database and a nationwide health insurance database. Materials and Methods: We used the following three databases: Cancer Registry Database of National Taiwan University Hospital (NTUH), National Health Insurance Research Database (NHIRD), and registry for catastrophic illness patients, a subset from NHIRD. We identified patients with RCC and analyzed the risk of subsequent malignancies in these patients. Results: Of the 1188 patients with RCC treated at NTUH, 141 (11.9%) had subsequent malignancies. Cancers in the colon, liver, prostate, lung and stomach were the five most common other primary malignancies. The nationwide analysis showed that 4.68% of the RCC patients had subsequent malignancies. The percentage was significantly higher than that in the general population in Taiwan. The five most common subsequent malignancies in patients with RCC were bladder, liver, colon, lung, and prostate cancer. The risk of developing these subsequent cancers in RCC patients was also significantly higher than that in the general population. Conclusion: Subsequent malignancies were noted in a high proportion of patients with RCC in Taiwan. It is a multifactorial process and the mechanism is still uncertain. This important issue warrants further studies to elucidate the mechanism.