ESTRO 2023 - Abstract Book

S1153

Digital Posters

ESTRO 2023

R. Basu Achari 1 , S. Chakraborty 1 , S. Ray 2 , A. Mahata 3 , S. Mandal 3 , J. Das 2 , K. Sarkar 1 , I. Mallick 1 , J. Bhaumik 4 , S. Chatterjee 1 , M. Arunsingh 1 , T. Bhattacharyya 1 1 Tata Medical Center, Radiation Oncology, KOLKATA, India; 2 Tata Medical Center, Nuclear Medicine, KOLKATA, India; 3 Tata Medical Center, Medical Physics, KOLKATA, India; 4 Tata Medical Center, Gynecologic Oncosurgery, KOLKATA, India Purpose or Objective This prospective observational study was undertaken to ascertain the influence of FDG-PET CT on chemoradiation (CTRT) decisions in patients with newly diagnosed, locally advanced carcinoma cervix (LACC) without para-aortic nodal disease. We report oncologic and patient reported outcomes. Materials and Methods Eligible patients underwent diagnostic FDG PET-CT after informed consent. PET-CT images were reviewed independently by 2 nuclear medicine experts and 2 radiation oncologists. Inconclusive findings were corroborated with histopathology. Digressions from pelvic CTRT plan, based on PET-CT results were documented and therapy adapted as applicable. Whole pelvis radiation (50Gy/25#/5weeks) with weekly cisplatin and brachytherapy (7 Gy to point A weekly x 3 fractions) was used in node negative disease. Dose escalated simultaneous integrated boost (SIB) 60Gy/25#/5weeks was delivered to involved pelvic nodes > 2 cm away from the uterine axis using helical tomotherapy. Post treatment PET-CT was done at 6 months. Toxicity was assessed using CTCAE criteria v4.0. Patient reported outcomes measures (PROMs) used the Functional Assessment of Cancer Therapy (FACT) general and cervix subscales at baseline, treatment completion, 3 months, 1 year and 3 years post treatment. Results Between November 2015 and January 2018, 77 of 85 patients screened, consented. Five patients with pelvis confined node negative disease withdrew consent after diagnostic PET-CT and received CTRT. Extrapelvic disease was seen in 12 (16%) patients (9 para aortic nodes, 2 metastases to liver and lung, 1 synchronous carcinoma breast); 60 patients were included in the final analysis. Figure 1 shows the impact of PET-CT radiotherapy volume-dose decisions. Overall, PET-CT resulted in decision changes in 10 of 77 (13%) patients screened for the study and 8 of 60 (13%) patients included in the study. At treatment completion 59 (98%) patients had grade 1(53%) and 2(45%) GI/GU/GYN toxicity, 1 (2%) had grade 3 GI toxicity and 5 (8.3%) had grade 3 neutropenia. With a median overall survival of 54.2 months (95% CI 52.8-58.3 95%) 5 year local failure, pelvic nodal and para aortic nodal free survival were 86.8% (95% CI 78.0 - 96.6%), 85.2% (95% CI 76.1 - 95.3%) and 85.2% (95% CI 76.2 - 95.4%) respectively. The FACT TOI scores improved as compared to baseline by 10.43 points at 3 months and did not show further deterioration (Fig.2) Late toxicity ( ≥ grade 2) in the form of abdominal pain (1.7%), distension (1.7%), cystitis (12.7%), diarrhea (2%), proctitis (13%) and vaginal stricture (49%) were reported at 5 years. Fig 1: Radiation therapy volume-dose decision change with PET-CT

FIg 2: Patient reported outcome measures