Impact of Retroperitoneal Lymphadenopathy (RPLN) on the Outcomes of Locally Advanced Gall Bladder Cancer (GBC) Following Chemotherapy (CT) or Chemotherapy Followed by Consolidation Chemoradiotherapy (CTRT).

Abstract

Retroperitoneal lymphadenopathy is considered a metastatic disease in GBC; however, some surgical series of radical surgery with enlarged RPLN who underwent RPLN dissection have shown results marginally inferior to those without enlarged RPLN. Radiological RPLN comprises a major proportion of advanced non-metastatic GBC. There is dilemma in the intent of treatment to be offered in such cases. We are reporting our series of outcome of GBC with RPLN treated with first-line CT followed by consolidation CTRT. Non-metastatic locally advanced GBC with good performance status (KPS ≥ 80) were initiated on first-line CT (cisplatin-gemcitabine), and thereafter, responders were evaluated by CECT-angiography and PET-CT scan for resectability. If found unresectable, they were offered consolidation CTRT to a dose of 45Gy by conventional fractionation (3D-CRT technique) along with concurrent capecitabine at 1250mg/m2 to GBC and regional lymphatics including RPLN. Thereafter, boost dose of 9Gy/5# was given to GBC only. Response assessment was done using CECT abdomen by RECIST criteria v 1.1. Outcomes (overall survival) of the two groups (RPLN vs non-RPLN) were computed with Kaplan-Meier survival curves and chi-square tests using SPSS v 20. Among 189 patients of advanced non-metastatic GBC recruited from 2011 to 2022, 80 had RPLN. The demographic features of both groups were comparable. Overall, 68% of the patients were women, 30% underwent upfront stenting for obstructive jaundice, and 90% had T3 and T4 disease. Only 10% had undergone upfront laparoscopic staging and had pathologically proven RPLN. Forty percent of the patients received four cycles of CT only and 50% of the patients received six cycles or more and 33% received CTRT. By RECIST criteria, 10% vs 16% achieved complete response (CR), 39% vs 41% achieved partial response (PR), 16% vs 15% achieved stable disease (SD), 2.7% vs 6% had disease progression (PD), and 14.5% vs 3.7% were non-evaluable in non-RPLN group vs RPLN group, respectively. 12% vs 6% could undergo radical surgery in non-RPLN group vs RPLN group (p = 0.03). The median OS was 9months (95% CI 7.6-10.3months) vs 10months (95% CI 8-9.8months) (p = NS) in non-RPLN group vs RPLN group, respectively. In those who received CT only, the median OS was 7months vs 8months, while in those who received CT followed by CTRT, the median OS was 14months vs 13months (p = 0.65) in non-RPLN group vs RPLN group, respectively. Based on this analysis, we conclude that RPLN constitutes a major proportion of advanced non-metastatic GBC and has outcomes similar to those without RPLN if treated with radical intent. RPLN should not be considered a metastatic disease and should be treated with radical intent.