ESTRO 2023 - Abstract Book

S1138

Digital Posters

ESTRO 2023

Meier method. Association between qualitative assessment, quantitative parameters, and OS, RFS, and CFS were analyzed using Univariate and Multivariate Cox regression. Results Among 1015 patients treated with RT between January 2015 and April 2020, 388 patients (300 women and 88 men) from 36 centers had a PET/CT at diagnosis and 4-6 months after treatment. Median age was 65 years (32-90). 147 patients (37.9%) had early-stage tumor and 241 patients (62.1%) locally advanced-stage tumor. 59 patients (15.2%) received RT and 329 (84.8%) CRT. Median follow-up was 35.52 months [CI95%:32.76-36.63]. Patients with CMR presented better 3-year RFS, CFS, and OS with 84.19% [CI95%:77.83-88.86], 84.66% [CI95%:77.22 89.33], and 88.64% [CI95%:82.48-92.73] compared to non-CMR patients with 42.12% [CI95%:33.36-50.58], 47.88% [CI95%:38.1-56.8], and 63.45 [CI95%:53.17-72.06] respectively (p < 0.0001). Among 242 patients with CMR, 213 (88%) were free of recurrence at 3 years and 29 (12%) presented a recurrence. Compared to CMR, partial response (HR 2.42 [CI95%:1.41-4.15] p 0.001), stability (HR 5.71 [CI95%:2.48-13.17] p < 0.001), and progression (HR 55.54 [CI95%:30.13-102.38] p < 0.001) were associated with worst 3-year RFS on multivariate analysis. Quantitative parameters were available for 154 patients from 3 centers. Considering T for primitive tumors and N for lymph nodes, following parameters were statistically significantly associated with 3-year RFS: SUV max (T) (HR 1.05 [CI95%:1.01-1.1] p 0.018), SUV peak (T) (HR 1.09 [CI95%:1.02-1.15] p 0.007), MTV41% (T) (HR 1.02 [CI95%:1-1.03] p 0.023), MTV41% (N) (HR 1.06 [CI95%:1.03-1.1] p < 0.001), MTV41% (T+N) (HR 1.02 [CI95%:1-1.03] p 0.005), and post treatment SUV max (HR 1.21 [CI95%:1.09-1.34] p < 0.001). Conclusion Treatment response assessed by PET/CT after RT for SCCA has a significant prognostic value in terms of RFS, CFS, and OS. PET/CT could be useful to assess treatment response and adapt follow-up, especially for patients with locally advanced stage tumors. Quantitative parameters could permit to identify patients with worst prognosis, but they should be evaluated in further prospective trials.

Poster (Digital): Gynaecological

PO-1409 Comparison of DVH of pelvic bone marrow in 2D vs VMAT and its clinical outcomes in carcinoma cervix

S. Naidu 1 , N. Madabattula 2 , J. Swathy.B 3

1 BIBI Cancer Hospital, Department of Radiation Oncology, Hyderabad, India; 2 Queens NRI Hospital, Department of Radiation Oncology, Vishakapatnam, India; 3 BIBI Cancer Hospital, Department of Radiation Oncology, HYDERABAD, India

Purpose or Objective Purpose

Radiotherapy (RT) occupies an important role in the treatment of gynecologic malignancies, notably cervical cancer. Most of the attention has been focused on gastrointestinal and genitourinary side effects mainly consisting of radiation-induced proctitis, fistulas, cystitis and small bowel obstruction. One side effect that has received very little attention is the hematologic toxicity (HT). However, with the increasing use of concomitant chemotherapy (CDDP), particularly in cervical cancer patients, HT is now one of the most common acute sequelae in gynecological patients undergoing RT. Aims and objectives To evaluate the DVH parameters of pelvic bone marrow and its sub sites and its clinical correlation with the hematological changes in patients of cancer cervix treated with conventional and VMAT Technique. Materials and Methods Total fifty patients were included in this study between October 2019 to December 2021 which was randomized into two groups- Conventional Radiotherapy arm & VMAT (Volumetric Modulated Arc Therapy) arm, both having 25 patients each. Radiotherapy dose delivered was 50Gy in 25 fractions at 2Gy/day it was followed by 3 applications of intracavitary brachytherapy of 7Gy/ fraction each. Dose Volume Histograms of pelvic bone marrow (BM) and the subsites- Ilium, Lower Pelvis, Lumbo Sacral Spine and were also calculated. Assessment of hematological toxicity was done by RTOG (Radiation Therapy Oncology Group) scoring criteria.