ESTRO 2023 - Abstract Book

S741

Monday 15 May 2023

ESTRO 2023

RPC had a median follow up (MFU) of 19.5 months and the 2-year overall survival (OS) was 50.2% for these patients. In BRPC, at the MFU of 14 months the 2-year OS of these patients was 28.2% and the ones undergoing R0/R1 resection was 47%. Patients having R0 resection had a significantly superior OS (55.3% vs 27.3%(p=0.020) . The 2-year DFS in BRPC patients treated with neoadjuvant therapy (NAT) comprising NACT+/-SBRT, followed by surgery was comparable to RPC patients with upfront surgery (37.2% vs 49.2%, p value=0.033). In LAPC patients at the MFU of 13 months, the median OS was 13 months. There was improved 2-year OS and DFS in patients receiving SBRT vs CT alone (p value=0.044 and 0.000 respectively). Conclusion Outcomes of BRPC patients who had resection post NAT were similar to the RPC patients treated with upfront surgery, proving the utility of NAT in BRPC patients. Addition of SBRT can further increase the resectability rate in BRPC patients not amenable for R0 resection. In unresectable LAPC, addition of SBRT significantly improved local control and survival outcomes compared to CT alone. PD-0894 Consolidation Chemoradiation vs Observation after Chemotherapy in Advanced Gall bladder cancer A. gupta 1 , S. agrawal 2 , R. rahul 3 , A. singh 3 , P. mishra 4 , R. saxena 3 1 SANJAY GANDHI INSTITUTE OF MEDICAL SCIENCES, RADIATION ONCOLOGY, LUCKNOW, India; 2 sanjay gandhi institute of medical sciences, radiation oncology, lucknow, India; 3 sanjay gandhi institute of medical sciences, surgical gastroenterology, lucknow, India; 4 sanjay gandhi institute of medical sciences, biostatistics, lucknow, India Purpose or Objective Gall Bladder Cancer (GBC) commonly presents in locally advanced or metastatic stage. First-line CT is the standard of care and those who progress and are unresectable are administered second line chemotherapy on disease progression. We are conducting a randomised study of consolidationChemoradiation(CTRT) vs observation in responders to first line CT (NCT05493956). This is based on the improvement in overall survival with consolidation CTRT in departmental database of 140 LA- GBC patients (in press, JGO, 2019,vol 5, suppl, 97). The primary endpoint is overall survival. We are reporting the toxicity due to CTRT. Materials and Methods Responders to first line CT (gemcitabine and cisplatin) will be randomised to CTRT vs observation after 4 cycles. The primary end point of the study is to compare OS between the two arms. The secondary end point is to compare progression free survival (PFS), acute and late toxicity, and quality of life between the two study arms. 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 resultant sample to achieve this aim is 140 (70 in each arm) over a duration of 4-5 years with a 10% attrition rate. CTRT will be delivered by 3DCRT along-with concurrent capecitabine @1250 mg/m2.The total target 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 CTRT were recorded using the CTCAE version 3.0. Dose volume data of Liver, Stomach, Duodenum and Kidney were correlated with the radiation induced side effects. After completion of treatment patients were followed up and assessed clinically every month and CT scan abdomen 3 monthly until disease progression Results A total of 132 patients have been enrolled. Median age of presentation is 53 years (IQR), of which 63% are females. 58% patients had T4 tumours and 42% had N2 and 27% underwent upfront stenting for obstructive jaundice. Both arms are well balanced demographically. Due to CTRT, 20% had grade 1 nausea, 20%, 14% and 9%, had anaemia (grade1,2,3), 30% grade 1 dyspepsia, 6% patients experienced GI bleed (3% grade 4), 16% patients’ hepatic dysfunction (gr 1). 9% patients could not complete RT mainly due to hepatic dysfunction (n=5), Covid (n=1). Dose volume corelation of side-effects will be presented in the meeting PD-0895 Response and survival function correlation with CyberKnife in 209 HCC pt with portal vein thrombus D. Dutta 1 , Y. Sreenija 1 , S. Reddy 1 , H. Nair 1 , N. SK 1 , A. Sasidharan 1 , R. Kannan 2 , S. George 2 , A. EH 3 , N.K. Haridas 4 , W. Jose 4 , P. Keechilat 4 , A. Valsan 5 , A. Koshy 5 , R. Balakrishnan 5 , S. Sadasivan 5 , U. Gopalakrishnan 6 , D. Balakrishnan 6 , S. OV 6 , S. Surendran 6 1 Amrita Institute of Medical Sciences, Radiation Oncology, Kochi, India; 2 Amrita Institute of Medical Sciences, Radiology, Kochi, India; 3 Amrita Institute of Medical Sciences, Medical Physics, Kochi, India; 4 Amrita Institute of Medical Sciences, Medical Oncology, Kochi, India; 5 Amrita Institute of Medical Sciences, Medical Gastroenterology, Kochi, India; 6 Amrita Institute of Medical Sciences, Surgical Gastroenterology, Kochi, India Purpose or Objective Prospective evaluation of stereotactic body radiotherapy (SBRT) with CyberKnife (CK) in hepatocellular carcinoma patients with macrovascular invasion (HCC-PVT). Materials and Methods Patients with inoperable HCC-PVT, good performance score (PS0-1) and preserved liver function (up to Child Pugh B7) were accrued after ethical and scientific committee approval [CTRI: 2022/01/050234] for treatment on CK (M6) and planned with Multiplan (iDMS V2.0). Triple-phase contrast computed tomography (CT) scan was done for contouring and gross tumor volume (GTV) included contrast enhancing mass within main portal vein and adjacent parenchymal disease. Dose prescription was as per risk stratification protocol (22- 50Gy in 5 fractions) while achieving the constraints of mean liver dose <15Gy, 800 cc liver <8Gy and the duodenum max of <24 Gy). Response assessment done at 2 months follow up for recanalization. Patient and treatment related factors evaluated for influence in survival function. Conclusion These observations suggest that consolidation CTRT is tolerable.