Abstract 316P
Background
Gallbladder cancer (GBC) is a rare malignancy representing 1.2% of all cancers according to GLOBOCAN 2022 data. It is considered one of the deadliest gastrointestinal (GI) cancers responsible for 89,055 (0.83%) deaths globally. GBC has a slowly progressive course leading to late diagnosis. Multiple primary malignancies (MPM) involving the gallbladder are rarely reported in the literature but significantly affect patient mortality. So this study aims to assess the risk of developing second primary GI malignancy following primary GBC.
Methods
We utilized the publicly accessible Surveillance, Epidemiology, and End Results (SEER) database registries, covering nearly 35% of the United States population. Data of patients diagnosed with primary GBC were extracted using SEER Stat 8.4.3 from 2000 to 2020. We used MPM-SIR session with a latency exclusion period of 2 months to calculate the standardized incidence ratio (SIR) as Observed/Expected (O/E), with 95% confidence interval (CI) and P-value considered significant if <0.05. We calculated the excess absolute risk (EAR) per 10,000.
Results
Along 120+ months of follow-up, Out of 20,597 patients who had GBC, 257 patients developed a GI second primary malignancy (SPM) with an O/E of 2.9 (P < 0.05; 95% CI: 2.56-3.28; EAR = 58.9). SPMs were observed in the esophagus with O/E = 0.77 (P > 0.05, 95% CI:0.16-2.24, EAR = -0.32), stomach (O/E = 2.99, P < 0.05, 95% CI:1.9-4.49, EAR = 5.35), small intestine (O/E = 5.91, P < 0.05, 95% CI: 3.15-10.1, EAR = 3.77), colon (O/E = 1.89, P < 0.05; 95% CI: 1.46-2.42, EAR = 10.39), rectum (O/E = 1.16, P > 0.05: 95% CI: 0.53-2.2, EAR = 0.43), liver (O/E = 2.85 < 0.05; 95% CI: 1.72-4.45, EAR = 4.31), intrahepatic, and extrahepatic bile duct had significantly increased risk for SPM with EAR=16.58 (O/E = 14.29, P < 0.05), and pancreas (O/E = 3.62, P < 0.05).
Conclusions
Patients with GBC are at significantly increased risk to develop second primary GI malignancies, especially in the stomach, small intestine, colon, liver, pancreas, intrahepatic and extrahepatic bile duct. Hence, clinicians and pathologists should maintain a high index of suspension when assessing such lesions, implementing regular follow-up for early detection and improved management of GI malignancies immediately after GBC diagnosis.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.