Abstract 87P
Background
Signet-ring cell carcinoma (SRCC) is a rare subtype of colorectal cancer constituting 0.5–2.5% of all adenocarcinomas. It is characterized by the presence of signet ring cells as the dominant malignant cell type. Developing gastrointestinal (GI) Second primary malignancies (SPMs) after SRCC is a sporadic event reported in the literature. There are no studies discussing the association between GI SPMs and SRCC. So, this study aimed to cover this gap and provide updated evidence to the literature about this rare type.
Methods
Data were extracted using te Surveillance Epidemiology and End Result (SEER) database. We used an MP-SIR session with multiple outcome analysis and a latency exclusion period of two months to assess the risk of GI SPMs in patients diagnosed with primary SRCC. Standardized Incidence Ratio (SIR) was calculated as observed/expected (O/E), and excess absolute risk (EAR) is per 10,000. Significance was achieved at 0.05 with a 95% confidence interval (CI).
Results
There was an increased risk for GI SPMs after SRCC in the 2–11 months interval with an O/E of 2.49 (P<0.05, EAR = 37.31), while along 10+ years of follow-up, the O/E was 3.08 (P<0.05, EAR = 59.20). After colorectal SRCC diagnosis, Small intestine SPMs in the 2–11 months interval had an O/E of 4.17 (P<0.05, 95%CI: 0.11-23.26, EAR = 1.97) while the overall O/E was 9.62 (P<0.05, EAR = 6.32) . However, the risk of liver SPMs had no significant risk (O/E=1.05, P>0.05, EAR = 0.12). The young age had no risk for GI SPMs (O/E =0.00, EAR = -0.15) compared to the middle age (O/E=7.66, P<0.05) and elderly (O/E of 2.36 (P<0.05). There was a slightly increased risk in chemotherapy patients (O/E 2.39, P<0.05, EAR = 49.29).
Conclusions
patients diagnosed with Colorectal SRCC are at significantly increased risk of developing GI SPMs for liver, small intestine, and esophagus. Middle and old age are more susceptible to suffer from GI SPMs based on the results of this study, we recommend all middle-aged and elderly with colorectal SRCC to undergo routine follow-ups starting from the time of diagnosis to minimize the burden of GI SPMs among cancer survivors.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.