Risk of second primary cancer in oral squamous cell carcinoma

Abstract Background: The incidence and survival of oral squamous cell carcinoma (OSCC) patients have increased in recent years. Understanding their long‐term survival aspects is essential for optimal treatment and follow‐up planning. Almost one in five cancers diagnosed occurs nowadays in individuals with a previous diagnosis of cancer. Methods: Patients diagnosed with primary OSCC during 1953‐2015 were retrieved from the Finnish Cancer Registry. Both standardized incidence ratios (SIR) and excess absolute risk (EAR) per 1000 person‐years at risk (PYR) of second primary cancer (SPC) were calculated relative to the general population. Results: Among 6602 first primary OSCC patients there were 640 (10%) SPCs. The SIR for SPCs was 1.85 (95% CI: 1.71‐1.99, P < .001) corresponding to an EAR of 8.78 (95% CI: 7.29‐10.26). Conclusions: Health care professionals should be aware of the second primary cancer risk after management of primary OSCC and patients need to be counseled about this phenomenon