A randomized study of consolidation chemoradiation (CTRT) vs observation after first-line chemotherapy (CT) in advanced gall bladder cancers (GBC): RACE-GB Study.

person Sushma Agrawal SGPGI, Lucknow, India info_outline Sushma Agrawal, Rahul Rahul, Ashish Singh, Prabhakar Mishra, Rajan Saxena

Authors person Sushma Agrawal SGPGI, Lucknow, India info_outline Sushma Agrawal, Rahul Rahul, Ashish Singh, Prabhakar Mishra, Rajan Saxena Organizations SGPGI, Lucknow, India, Sanjay Gandhi Postgraduate institute of Medical Sciences, Lucknow, India, Sanjay gandhi Postgraduate Institute of medical Sciences, Lucknow, India Abstract Disclosures Research Funding Conquer Cancer Foundation of the American Society of Clinical Oncology Conquer Cancer Foundation of the American Society of Clinical Oncology Background: CT (gemcitabine plus cisplatin) is the standard of care for patients presenting with unresectable advanced GBC but their prognosis remains poor. The value of CTRT after CT is uncertain. We therefore conducted a randomised trial evaluating consolidation CTRT versus Observation after four cycles of CT in those patients whose disease did not progress during CT (NCT05493956). Methods: Responders (partial response and stable disease) to 4 cycles of CT were randomised to CTRT vs observation (n=135). CTRT was delivered by 3D-Conformal Radiation Therapy along-with concurrent capecitabine @1250 mg/m2. The dose of RT was 45 Gy in 25 fractions to GBC and lymphatics followed by a boost of 9 Gy in 5 fractions to the GBC. The primary endpoint was overall survival which was calculated from the date of randomisation. The trial is designed to detect an improvement in 2-year OS from 8% in the control arm to 25% in study arm with 80.0% power at a 0.05 significance level. The required sample size was 130 (65 in each arm) over a duration of 4-5 years. CTRT was delivered by 3DCRT along-with concurrent capecitabine @1250 mg/m2. The dose of RT was 45Gy in 25 fractions to GBC and lymphatics followed by a boost of 9 Gy in 5 fractions to the GBC. Toxicities documented during CT and CTRT were recorded using the CTCAE version 3.0. and RTOG criteria respectively. Chi square test and Survival analysis was performed for the data analysis. Demographic data and CTRT Dose volume data were correlated with side effects and survival. Statistical analysis was performed with SPSS version-23. Results: 67 patients were randomized to observation and 68 to CTRT. Their demographic characteristics were well balanced. 63% were women, 58% had T4 tumours, 42% had N2, 27% needed stenting for obstructive jaundice. The median overall survival in the CTRT arm was 10 months versus 4 months in the observation arm (HR 0.47 [95% CI 0.33-0.68] p=0.001). Adverse events (grade 3 or higher) due to CTRT included the following: Nausea 3%, Anemia 9%, GI bleed 6%, hepatotoxicity 13%. Updated survival data and prognostic factors affecting overall survival will be presented in the meeting. Conclusions: CTRT after 4 cycles of CT significantly prolonged overall survival but was also associated with adverse events. Clinical trial information: NCT05493956.