Survival outcomes with observation or adjuvant therapy in elderly patients with biliary tract cancer.

Abstract

e16230 Background: The impact of adjuvant therapy (AT) on overall survival (OS) for biliary tract cancer (BTC) is contested. The BILCAP study suggested an improvement in OS with adjuvant capecitabine compared to observation. This was not apparent in the intention to treat population. Importantly, none of the patients in the study was older than 70 years. Considering the toxicity of AT and conflicting results of efficacy, the role of AT in older adults with BTC needs to be thoroughly assessed. We hypothesized that AT is not associated with significant benefit in the elderly. Methods: We performed a retrospective review of patients with resected BTC; gall bladder cancer (GBC), intrahepatic cholangiocarcinoma (ICC), and extrahepatic cholangiocarcinoma (ECC) using the National Cancer Database (NCDB) PUFs (2004-2019). We limited analysis to patients aged >= 70 years. We compared clinical characteristics and outcomes in those who received AT (including chemotherapy and chemotherapy + radiation) within 6 months after resection, and those who did not (Obs). We performed propensity score matching analysis of both groups (matched for age, sex, race, Charleson-Deyo score, AJCC pathologic T stage among others) and assessed survival by Kaplan-Meier analysis. Results: We identified 8,091 elderly patients with T1-T3/N1-N2 resected BTC. The majority had GBC (76.7%), and 3, 041 (38%) were aged >= 80 years (median 78 years). Only 2, 632 (32.5%) received AT. Of these, 1,304 (50%) received chemotherapy and radiation. Median OS was higher in the Obs vs the AT group (24.3 months, vs 20.2 months, P < 0.0001) and the five-year survival was also higher in the Obs group (29.1% vs 22.6%, P<0.001). Survival also favored the Obs group in a propensity score matched cohort of 835 patients per group (median OS 33.1 vs 19.5 months, P <0.0001). On multivariable analysis AT was associated with a higher hazard of death (HR 1.21, CI 1.13-1.29, P <0.001). Age >=80 (HR 1.39, CI 1.32-1.47, P<0.001), GBC ( HR 1.29, CI 1.20-1.39, P<0.001) were also associated with worse survival. Compared to diagnosis between 2004-2009 diagnosis in 2010- 2015 (HR 0.83, CI 0.78- 0.89) and 2016- 2019 (HR 0.74 CI 0.67-0.8, P <0.001) were associated with improved OS. Conclusions: In patients >=70, AT for BTC was not associated with improved OS and was actually associated with a higher hazard of death compared Obs. Based on these results, the role of AT for BTC in the elderly needs to be examined prospectively.