ESTRO 2023 - Abstract Book

S1154

Digital Posters

ESTRO 2023

Conclusion PET-CT based treatment planning resulted in major decision changes in 13% patients. PET adapted and pelvic nodal dose escalated pelvic CTRT showed improvement in PROMS over time with encouraging pelvic control and survival.

PO-1426 Analysis of interim response in stage IVA carcinoma cervix and its influence on treatment outcome.

P. Tejaswi 1 , K. Kattimani 2 , B. Patil 3 , S. Nadkarni 3 , S. Kumari 1

1 Karnataka Cancer Therapy and Research Institute, Radiation Oncology, Hubballi, Karnataka, India; 2 Karnataka Cancer Therapy and Research Institute, Medical Oncology, Hubballi, Karnataka, India; 3 Karnataka Cancer Therapy and Research Institute, Surgical Oncology, Hubballi, Karnataka, India Purpose or Objective FIGO stage IVA cervical cancer represents a small subset of patients (3.1%). Concurrent chemoradiation (CT+RT) in these patients, results in modest outcome. There are studies which reported partial response and in few cases complete response in stage IVA with systemic therapy. Hence in this trial, we are planning to improve the outcome based on interim response after 3 cycles of chemotherapy (CT), in the patients initially planned for 6 cycles of CT. Thereby assessing the effect of Neo-adjuvant chemotherapy (NACT) followed by concurrent CT+RT and brachytherapy, in terms of treatment outcome and toxicities. Materials and Methods 65 patients included in this Monocentric Prospective Longuiditinal Interventional study, as per inclusion & exclusion criteria. Initially these patients were planned for 6 cycles of three weekly CT with Carboplatin AUC 5-6 and Paclitaxel-175mg/m2 per Cycle. After 3rd cycle, response assessment done using clinical, radiological (RECIST 1.1 and PERCIST) and cystoscopic +/- colonoscopic findings. Patients showing complete or partial response, are subjected to chemoradiation 45Gy/25fr via conformal technique with concurrent weekly cisplatin 40mg/m2 followed by fractionated brachytherapy. Patients with no response during interim analysis, are administered further 3 cycles of 2nd line CT and assessed for response. Patients are followed up for a minimum period of 2 years to assess overall survival, disease free survival, recurrence rate and toxicities. Data is entered in MS-Excel and analyzed in SPSS V25. Shapiro wilk test is applied to find normality, McNemar and Marginal homogeneity test used in comparison of paired samples. Friedman test is applied to find significance with P<0.05 is considered as statistically significant. Results In this study, patients age ranged between 34-66 years. Clinically the mean tumor size -7.4cm, mean tumour volume on MRI- 277.22cc with lymph nodal disease in 87.69% and mean primary SUV uptake- 3.9 in PET-CT with no distant metastasis at diagnosis. Infiltration of bladder, rectum and both seen in 76.9%, 13.8% & 9.2% respectively. Post 3rd cycle CT, statistically significant complete & partial response was seen in 9.23% & 76.92% with p=0.001. These patients received the standard CT+RT followed by brachytherapy. None of the patients reported acute grade 3 toxicities as per CTCAE v5.0 and RTOG toxicity grading. Post treatment follow up at 12th week shows clinical and radiological response with p<0.001. At the end of 2 years follow up, 13.84% recurred and 58.46% patients had achieved disease free survival with no chronic toxicities. Conclusion Interim response assessment can serve as useful predicator for analyzing clinical efficacy of planned chemotherapy. NACT followed by CT+RT can be a feasible option for patients with stage IVA carcinoma cervix as per study findings. Randomized phase III trial is required to establish the value of NACT followed by CT+RT versus CT+RT alone in stage IVA cervical cancer patients and we recommend the same.