ESTRO 2022 - Abstract Book

S1023

Abstract book

ESTRO 2022

The mean IORT administration time was 9.8 minutes. Adjuvant glandular radiotherapy was performed with a median interval of 6.6 months during which systemic treatment was given. The adjuvant fractionation schedules used were 40.05Gy in 15 sessions in 62.5% and 26Gy in 5 sessions in 37.5%. At a median follow-up of 25 months, there was no acute or chronic toxicity > G2, and no local or distant relapses have been observed. Conclusion The application of IORT as an overimpression of the tumour bed in patients with early stage breast cancer and poor prognostic subtypes allows to secure the bed until other adjuvant therapies are given. A comparison between boost administration with IORT vs. integrated with external beam radiotherapy in these patients would remain to be done in the future.

PO-1204 Use of Complementary medicine during adjuvant Radiotherapy in breast cancer

R. Buecker 1 , U. Schaefer 1

1 Universitätsklinikum OWL der Universität Bielefeld Campus Klinikum Lippe, Abteilung fuer Strahlentherapie und Radioonkologie, Lemgo, Germany Purpose or Objective Complementary medicine (CM) is used widely in cancer patients, mostly in palliative treatment regimens or during chemotherapy. In contrast, the use of CM during curative Radiotherapy (RT) is less frequent. The aim of this study was to evaluate the influence of CM with regard to toxicity and recurrence during postoperative radiotherapy for breast cancer. Materials and Methods Between 2010 and 2013 all patients intended for adjuvant radiotherapy for breast cancer received a questionnaire concerning the use of CAM e. g. Vitamins, trace elements, enzymes, natural herbs etc. (yes/no) and if yes what kind. At the time Radiotherapy was applied with 50.4 Gy to the whole breast and a Boost of 10.8 Gy in 6.5 weeks. 6 weeks after radiotherapy the side effects were analyzed according RTOG grading. Follow up for progression rates was done yearly until January 2018. To determine whether there is a significant difference between the expected frequencies and the observed frequencies, a chi-squared test was used. All events were collected until January 2018. Results A total number of 879 patients with breast cancer completed the questionnaire, 641/879 (73 %) patients did not take any complementary medicine (non CAM) and 238/879 (27 %) patients took CAM. There were almost 40 different products mentioned. 137/238 (57.6 %) patients took one CAM product, 86/238 (36.1 %) two, and 15/238 (6.3 %) more than two CAM products. The most common products were magnesium (Mg) in 71/238 (30 %) patients followed by selenium in 38/238 patients (16 %). The RT side effects (Dermatitis RTOG grade 0, I, II, III/IV) 6 weeks after completion of RT were as follows: in the non CAM group 53 % grade 0, 41 % grade I, and 6 % grade II, 0 % grade III/IV. And in the CAM group 54 %, 38 %, 8 %, and 0.4 % respectively. The corresponding side effects for the group taking magnesium were 51 % 42 %, 6 % and 1 % and for the selenium group 47 %, 47 %, 5 % and 0 %). There was no significant difference in side effects between the non CAM and CAM patients, respectively magnesium and selenium. The sum of all registered disease progression (0 years – 5 years) were in the non CAM group 6.4 %, in the CAM group 6.3 %, in the magnesium group 5.6 % and in the selenium group 7.9 %, no significant difference could be detected between all groups. Conclusion In this cohort, 27 % of patients used CAM during adjuvant radiotherapy of breast cancer. The most commonly used product is magnesium followed by selenium. A significant influence of CAM on subacute RT side effects or disease progression could not be identified. However, the higher rate of local and systemic failure in the selenium group appears remarkable. Therefore, this analysis will be further continued with a higher number of patients.

PO-1205 Early outcomes of hypofractionated radiotherapy in locally advanced stage T4 breast cancer

Z. Naimi 1 , N. Nsiri 1 , M. Bohli 1 , R. Ben Amor 1 , A. Hamdoun 1 , J. Yahyaoui 1 , L. Kochbati 1

1 Abderrahmen Mami Hospital Ariana, Radiation Oncology Department, Ariana, Tunisia

Purpose or Objective The aim of this study was to assess early outcomes and safety of hypofractionated radiotherapy in non-metastatic locally advanced stage T4 breast cancer. Materials and Methods Fifty patients irradiated between 2017 and 2020 for non-metastatic locally advanced stage T4 breast cancer (BC) were retrospectively evaluated. All patients underwent 3D conformal hypofractionated radiotherapy: 40 Gy delivered in 15 daily fractions of 2.67 Gy +/- additional boost of 13.35 Gy. Disease free survival, metastasis free survival, acute and late radiation induced toxicity were evaluated.