ESTRO 2022 - Abstract Book

S1029

Abstract book

ESTRO 2022

We designed a non randomized prospective controlled trial on caloric restriction (CR) or intermittent fasting (IF) in overweight-obese patients with breast or prostate cancer referred for curative radiotherapy. Materials and Methods Patients who meet inclusion criteria underwent CR or IF depending on the patient's preference (according to their lifestyle). CR consisted in reduction in 25% of the basal caloric intake and IF of suppressing intake for at least 16 hours. All patients had to begin their intervention at least 2 weeks before radiotherapy. The primary objective was to investigate the feasibility of a nutritional intervention concurrent with radiation therapy. The adherence was defined as a 5% reduction in the body weight. Secondary objectives included change in anthropometric measures (weight and waist circumference) and serum levels of glucose, insulin and lipids. We also evaluated acute toxicity and quality of life reports (not included in this primary report). Results From April 2021 and September 2021 we recruited 16 patients. One patient withdrew from the trial before treatment and 1 patient did not receive radiotherapy. Of the 14 patients available for analysis, 12 were women with breast cancer and luminal ductal carcinoma was the most common histologic subtype. 7/12 received some kind of chemotherapy (neoadjuvant, adjuvant or both) and 8/12 received endocrine therapy. 9/12 underwent CR and 3/12 IF. All patients underwent whole breast radiotherapy (± regional nodal irradiation) and 7/12 simultaneous integrated boost to the tumor bed up to 45,75 Gy. 2/14 patients were men with operated prostate cancer and Gleason score 6 and 7. All of them had initiated androgen deprivation therapy, underwent IF and received a dose of radiotherapy 51 Gy in 17 fractions to the prostate bed or equivalent EQD2. At the end of October 2021, 8/12 patients had completed 12 weeks follow up. There was a weight loss of 4,2 kg in average, and 6/8 patients lost 5% or more of the initial weight (true adherence). Mean reduction in waist circumference was 4,9 cm and serum levels of glucose, triglycerides and insulin showed mean reductions of 1.3 mg/dL, 24.2 mg/dL and 2.1 uU/mL respectively. Conclusion Implementing a nutritional intervention like CR o IF in patients receiving radiotherapy is feasible and effective in reducing body weight and waist circumference and showed to improve serum levels of glucose, insulin and lipids in a short period of time. 1 Seoul National University Hospital , Radiation Oncology , Seoul, Korea Republic of; 2 Seoul National University , College of Medicine , Seoul, Korea Republic of; 3 Seoul National University Bundang Hospital , Surgery, Seongnam, Korea Republic of; 4 Seoul National University Bundang Hospital , Plastic and Reconstructive Surgery, Seongnam, Korea Republic of; 5 Seoul National University Bundang Hospital , Radiation Oncology , Seongnam, Korea Republic of Purpose or Objective The aim of this study is to evaluate cosmetic outcomes of the reconstructed breast in breast cancer patients using anomaly score (AS) detected by generative adversarial network (GAN) deep learning algorithm. Materials and Methods A total of 251 normal breast images from patients who underwent breast-conserving surgery were used for training anomaly GAN network. GAN-based anomaly detection was used to calculate abnormalities as an AS with Z-score standardization. Then, we retrospectively reviewed 61 breast cancer patients who underwent mastectomy followed by breast reconstruction with autologous tissue or tissue expander. All patients were treated with adjuvant radiation therapy (RT) after breast reconstruction and computed tomography (CT) was performed three time points; before RT (Pre-RT), one year after RT (Post-1Y), and two years after RT (Post-2Y). Results Compared to Pre-RT , Post-1Y and Post-2Y demonstrated higher AS, indicating more abnormal cosmetic outcomes on paired- T test (Pre-RT vs. Post-1Y, P=0.015 and Pre-RT vs. Post-2Y, P=0.011). Pre-RT AS was significantly higher in patients having major breast complications (P=0.016). Autologous reconstruction showed better AS than tissue expander insertion at pre- RT (2.00 vs. 4.19, P=0.008) and post-2Y (2.89 vs. 5.00, P=0.010). Linear mixed effect model revealed that days after baseline were significantly associated with increasing AS (P=0.007). Also, the use of tissue expander was associated with steeper rise of AS, compared with autologous tissue (P=0.015). Fractionation regimen (conventional fractionation vs. hypofractionation) was not associated with the change of AS (P=0.389). Conclusion Anomaly score detected by deep learning might be feasible in predicting cosmetic outcomes of RT-treated patients with breast reconstruction. AS should be validated in clinical trial settings. PO-1215 Feasibility of anomaly score detected with deep learning in irradiated breast with reconstruction D. Kim 1 , S.J. Lee 2 , E.K. Kim 3 , E. Kang 3 , Y. Myung 4 , C.Y. Heo 4 , I.A. Kim 5 , B. Jang 5

PO-1216 Factors affecting cardiac dose in left-sided whole breast radiotherapy in a single institution

A. Tot 1,2 , B. Petrovi ć 1,3 , M. Marjanovi ć 4,3 , I. Gencel 1 , N. Golubovac 1 , O. Ivanov 5,6 , J. Li č ina 5,6 , M. Mitri ć -A š kovi ć 5