Conditional probability of survival in gallbladder carcinoma as a prognostic tool for long term survivors.

Abstract

455 Background: Gallbladder carcinoma (GBC) often presents in an advanced stage and despite radical resection and nodal harvest, prognosis remains poor. Conventional survival statistics do not account for time elapsed from diagnosis and may not carry relevant prognostic information for long term survivors. This study sought to estimate the conditional probability of survival (CS) in patients of GBC. Methods: Patients with GBC were identified from the Surveillance, Epidemiology and End Results (SEER) database (1988-2012). Overall probability of survival (OS) was estimated using Kaplan-Meier method. Cumulative incidence method was employed to calculate CS. Results: Of 15,046 GBC patients identified, Stage IV disease was the most common presentation (n = 5625). Surgical intervention was reported in 9,720(65%) patients with cholecystectomies (n = 8254) outnumbering radical resections (n = 1116). 3-year OS for all stages was 18% and conditional probability of surviving additional 3 years (CS3) at 1, 2 and 3 years from diagnosis was 42%, 57% and 66% respectively. Stage III and IV disease had 3-year OS rates of 19% and 3% respectively while CS3 increased progressively with each year survived(33% and 17% at 1 year, 51% and 34% at 2 years, 60% and 56% at 3 years). Conclusions: Conditional probability of survival is favorable in patients surviving one year from diagnosis and shows an increasing trend with time. Improvements in survival are more substantial in patients with adverse initial prognosis. Conditional survival provides valuable information on prognosis to patients after curative surgery and can be the basis of follow-up guidelines.