Adjuvant Gemcitabine Plus Cisplatin and Chemoradiation in Patients With Gallbladder Cancer

Importance: There is limited evidence with regard to the benefit of adjuvant chemotherapy chemoradiotherapy in resected gallbladder cancers (GBCs). Objective: To establish a baseline survival rate for operated GBCs in patients receiving either gemcitabine plus cisplatin (GC) or capecitabine and capecitabine concurrent with chemoradiation (CCRT). Design, Setting, and Participants: The GECCOR-GB study was a multicenter, open-label, randomized phase 2 noncomparator "pick the winner" design trial of adjuvant GC and CCRT in patients with resected histologically confirmed adenocarcinoma or adenosquamous carcinoma of the gallbladder, (stage II/III) with no local residual tumor (R0) or microscopic residual tumor (R1). The study was carried out in 3 tertiary cancer institutions in India. Patients 18 years or older with adequate end-organ functions, and Eastern Cooperative Oncology Group Performance Status of 1 or lower between May 2019 and February 2022 were enrolled. The cutoff date for data analysis was February 28, 2023. Interventions: Patients were randomized 1:1 to receive either GC every 3 weeks (maximum of 6 cycles) or CCRT comprising capecitabine with concurrent chemoradiation (capecitabine concurrent with radiotherapy) sandwiched between capecitabine chemotherapy. Main Outcomes and Measures: The primary outcome was disease-free survival (DFS) at 1 year in randomized patients. This study was conducted as 2 parallel, single-stage phase 2 clinical trials. Within each treatment arm, a 1-year DFS rate of less than 59% was considered as insufficient activity, whereas a 1-year DFS rate of 77% or higher would be considered as sufficient activity. Results: With a median follow-up of 23 months, 90 patients were randomized, 45 in each arm. Overall, there were 31 women (69%) and 14 men (31%) in the GC arm with a mean (range) age of 56 (33-72) years and 34 women (76%) and 11 men (24%) in the CCRT group with a mean (range) age of 55 (26-69) years. In the GC and CCRT arms, 1-year DFS and estimated 2-year DFS was 88.9% (95% CI, 79.5-98.3) and 74.8% (95% CI, 60.4-89.2), and 77.8% (95% CI, 65.4-90.2) and 74.8% (95% CI, 59.9-86.3), respectively. Completion rates for planned treatment was 82% in the GC arm and 62% in the CCRT arm. Conclusions and Relevance: In this randomized clinical trial, GC and CCRT crossed the prespecified trial end points of 1-year DFS in patients with resected stage II/III GBCs. The results set a baseline for a larger phase 3 trial evaluating both regimens in operated GBCs. Trial Registration: ClinicalTrials.gov Identifier: CTRI/2019/05/019323I.