Predictors of Toxicity in a Randomized Study of Consolidation Chemoradiation Versus Observation After First Line Chemotherapy in Advanced Gall Bladder Cancers.

Purpose: Gall bladder cancers (GBC) usually presents in advanced stage. First-line chemotherapy (CT) is the standard of care, and there is no other option for responders than to wait for disease progression. We conducted a randomized study of consolidation chemoradiation (CTRT) versus observation in responders to first line CT (NCT05493956), which showed an improvement in overall survival by 6 months and therefore is practice changing. We are reporting the toxicity and factors predicting toxicity due to CTRT so that it informs appropriate patient selection. Methods and Materials: Responders to first line CT (partial response, stable disease) were randomized to CTRT versus observation after 4 cycles. CTRT was delivered by 3D conformal radiotherapy (along-with concurrent capecitabine at 1250 mg/m Results: Among 135 patients enrolled both arms are well balanced demographically, and 58% patients had T4 tumors, 42% had N2 and 15% had paraaortic lymph node, and 27% underwent upfront stenting. Grade 3 adverse events, such as anemia, dyspepsia, hepatotoxicity (Child Pugh B), and gastrointestinal bleed due to CTRT was observed in 9%, 1.5%, 13%, and 5.8%, respectively. Age >58 years ( Conclusions: Consolidation CTRT is tolerable in those with PTV1 volume less than 800 cc.