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).

Introduction: 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.

Materials and methods: 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 45 Gy by conventional fractionation (3D-CRT technique) along with concurrent capecitabine at 1250 mg/m² to GBC and regional lymphatics including RPLN. Thereafter, boost dose of 9 Gy/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.

Results: 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 9 months (95% CI 7.6-10.3 months) vs 10 months (95% CI 8-9.8 months) (p = NS) in non-RPLN group vs RPLN group, respectively. In those who received CT only, the median OS was 7 months vs 8 months, while in those who received CT followed by CTRT, the median OS was 14 months vs 13 months (p = 0.65) in non-RPLN group vs RPLN group, respectively.

Conclusions: 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.