Results of the secondary analysis of the SWOG S0809 trial indicate that nodal status did not impact survival outcomes achieved with adjuvant chemoradiation postresection in patients with extrahepatic CCA or gallbladder cancer.
The phase 2 SWOG S0809 Intergroup Trial had previously demonstrated improved overall survival (OS) with adjuvant treatment with capecitabine and gemcitabine followed by radiotherapy and concurrent capecitabine in patients with extrahepatic cholangiocarcinoma (CCA) or gallbladder cancer (GBC) compared with historical controls. Secondary analysis of SWOG S0809 (ClinicalTrials.gov Identifier: NCT00789958) evaluated the effect of adjuvant chemoradiation on node-positive patients. Results of the analysis were presented at the 2021 American Society of Clinical Oncology Annual Meeting.
In this analysis, patients with stage pT2-4, N+, or positive-margin resected extrahepatic CCA or GBC were included. Adjuvant chemotherapy comprised 4 cycles of gemcitabine (1000 mg/m2 on day 1 and day 8) and capecitabine (1500 mg/m2/day on days 1-14) every 21 days, followed by concurrent capecitabine (1330 mg/m2/day) and radiotherapy (45 Gy to regional lymphatics; 52.5-59.4 Gy to tumor bed). Correlations among nodal status, resection margin, and other clinicopathologic factors; patterns of recurrence; and survival were analyzed. Cox regression models were used to estimate the prognostic significance of nodal status.
A total of 69 patients were included in the analysis—66.7% (46 of 69) of the patients with extrahepatic CCA and 33.3% (23 of 69) of the participants with GBC. Overall, 24 patients had N0 disease and 45 had N1 disease. The patient characteristics of the N0 and N1 cohorts were largely comparable. Those in the N0 cohort were predominantly female (70.8%), whereas those in the N1 cohort were mostly male (55.6%; P = .04). The N1 cohort mainly had extrahepatic CCA (73.9%), and 50% of the N0 cohort had GBC.
Nodal status did not significantly impact OS or disease-free survival (DFS). The 2-year OS was similar between the N0 and N1 tumor cohorts (70.6% vs 60.9%, respectively; P = .11), as was 2-year DFS (62.5% vs 49.8%, respectively; P = .20). The 2-year DFS in patients in the N1 tumor cohort, however, was significantly prolonged compared with the historical rate (49.8% vs 29.7%, respectively; P = .004). N1 tumors compared with N0 tumors showed similar 2-year local recurrence rates (11.1% vs 8.3%, respectively; P = .88) but higher 2-year distant recurrence rates (42.2% vs 25.0%, respectively; P = .04).
Based on these results, the investigators concluded that adjuvant chemoradiation postresection provides favorable outcomes in patients with extrahepatic CCA and GBC, regardless of nodal status, with a positive impact on local control in patients with N1 tumors.
Source: Gholami S, Duon MT, Horowitz DP, et al. Does adjuvant chemoradiation benefit patients with lymph node-positive biliary tract cancer? A secondary analysis of SWOG S0809. J Clin Oncol. 2021;39(suppl_15):4104-4104.
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