Introduction: Serrated polyposis syndrome (SPS) is a high-risk factor for colorectal cancer (CRC); however, prognostic differences based on patient characteristics are poorly understood. This exploratory study investigated the impact of concomitant or a history of CRC at the time of SPS diagnosis on long-term prognosis. Methods: Of the 70 patients diagnosed with SPS between 2009 and 2023, 55 with 1-year follow-up were included in this single-center retrospective cohort study. Patients with a history of CRC were assigned to the CRC (+) (n=16) group and those without a history of CRC to the CRC (-) group (n=39). We compared the baseline characteristics, surveillance findings, and long-term outcomes, including new extracolonic cancer incidence and overall survival, between the groups. Results: The CRC (+) group had a significantly higher prevalence of personal history of other cancers (38% vs. 10%, p=0.024) and family history of cancer (69% vs. 38%, p=0.048). The incidence of new extracolonic cancers during follow-up after the diagnosis of SPS was significantly higher in the CRC (+) group (25%; 4/16) than in the CRC (-) group (3%; 1/39) (p=0.012). Overall survival was also significantly poorer in the CRC (+) group (two deaths, 13%) than in the CRC (-) group (p=0.044). Conclusions: A history of CRC in patients with SPS is associated with a higher incidence of new extracolonic cancer and poorer overall survival. These findings suggest that management strategies should extend beyond standard colorectal surveillance to comprehensive systemic monitoring. Therefore, the validation of these results in larger prospective cohorts is warranted.
Shimohara et al. (Thu,) studied this question.