ESTRO 36 Abstract Book

S646 ESTRO 36 _______________________________________________________________________________________________

results of such comparisons as reported by the authors of the studies. Results The search strategy retrieved 2224 references. Of these, 271 publications, corresponding to 182 trials fulfilled the eligibility criteria and were the subject of this analysis. HRQOL was considered as endpoint in 38 (20.8%) of the included studies and it was used as primary endpoint in 10.9% of them. Most trials (84.0%) focused on biomedical intervention. Of 22 trials that had a positive primary endpoint, 18 had a significant benefit in HRQOL, in favor of the experimental arm. Of 13 trials that had a negative primary endpoint, there were no differences in HRQOL among the study groups. In regards of HRQOL assessment, statistical methods and definition of timing of evaluation were described 32 (84.2%) and 36 (94.7%) trials, respectively. The European Organization for the Research and Treatment of Cancer Quality-of-Life Questionnaire (EORTC-QLQ) (C-30 with or without BR23) alone or plus additional measures was the most frequently used tool in 17 (44.7%) of 38 studies. Eighteen trials (47.4%) used two or more HRQOL assessment tools. The Functional Assessment of Cancer Therapy (global or breast) with or without additional measures were used in 9 (23.6%) of 38 trials. Conclusion This analysis shown that HRQOL has been infrequently investigated in phase III trials of radiation therapy in breast cancer. Statistical methods and timing of evaluation were not always described with sufficient detail. Significant benefit in HRQOL was frequently reported in those trials that reported a positive primary endpoint. EP-1193 Hypofractionated external beam radiation therapy for breast cancer. The new standard? I. Nobre Góis 1 , A. Ponte 1 , J. Casalta-Lopes 1 , T. Teixeira 1 , P. Vicente 1 , M. Borrego 1 1 Hospitais da Universidade de Coimbra, Servico de Radioterapia, Coimbra, Portugal Purpose or Objective Hypofractionated external beam radiation therapy (HRT) consists in the administration of higher than conventional dose per fraction, leading to reduced overall treatment time and increased compliance to treatment, at lower costs for hospital and patient. Several randomized phase III trials show HRT as an alternative to conventional fractionation in the adjuvant setting after breast conserving surgery, with similar outcomes regarding local control and side effects. The most commonly used HRT schedules include 42.6 Gy / 16 fractions or 40 Gy / 15 fractions, as stated in international recommendations. In this study we aim to assess toxicity after conservative surgery followed by HRT in breast cancer patients. Material and Methods Prospective inclusion of patients with invasive breast cancer submitted to breast conserving surgery, treated in our Radiation Oncology department between March 2014 and June 2016, aged over 60 years, hormone receptor- positive, HER2-negative, tumor histological grade G1-G2, margins exceeding 1 mm, staged pT1-T2 pN0 cM0, with an adequate dosimetric study. A dose of 40 Gy was delivered in 15 fractions (2.67 Gy / fraction), followed by a boost to the tumor bed of 10 to 16 Gy in 5 to 8 fractions (2.0 Gy / fraction). Acute toxicity (CTCAE4.0 scale) and heart and lung dosimetric parameters were recorded. Results Of the 74 patients accepted for HRT, 2 were excluded due to failure on dosimetric assessment or the presence of complex sclerosing lesion. 72 included patients with a median age of 65 years (60-79 years), tumors mainly located on the left breast (58.3%) and upper quadrants

(65.3%). Invasive carcinoma not otherwise specified (NOS) was present in 91.7%, staged pT1b in 37.5% and pT1c in 52.8%. Boost was prescribed with a dose of 10Gy in 63.9% of patients.The median values of the dosimetric parameters evaluated were Heart V25 of 3.10% (0%- 16.68%) and Lung V20 of 11.13% (2.5%-24.38%).All patients completed the originally planned schedule, 97.2% presenting acute cutaneous toxicity (any grade), grade 3 in only 5 patients (6.9%). No other complications were registered during treatment.Median follow-up was 10 months (3-25 months). In the first follow-up visit toxicity was observed in 55.6% patients, with erythema/pigmentation (grade 1-2) in 29.2%, breast edema in 23.5% and fibrosis in 8.3%. One patient had symptomatic radiation related pneumonitis, with full resolution after therapy.Of the 47 patients already observed in subsequent follow-up appointments, there was visible fibrosis in 11 patients, edema in 7 patients, breast shrinkage in one patient and telangiectasia in another patient. Conclusion Hypofractionated radiation therapy schedules allow for excellent treatment compliance with an acceptable toxicity profile and a good cosmetic result. A longer follow-up will allow increased accuracy in late side effects evaluation. EP-1194 Dose-volume relationship for acute skin erythema in patients undergoing breast irradiation F. Badenchini 1 , F. Bonfantini 2 , M. De Santis 3 , S. Gay 1 , F. Palorini 1 , A. Cicchetti 1 , T. Rancati 1 , M. Carrara 2 , T. Giandini 2 , E. Pignoli 2 , R. Valdagni 3 , L. Lozza 3 1 Fondazione IRCCS Istituto Nazionale dei Tumori, Prostate Cancer Program, Milan, Italy 2 Fondazione IRCCS Istituto Nazionale dei Tumori, Medical Physics, Milan, Italy 3 Fondazione IRCCS Istituto Nazionale dei Tumori, Radiation Oncology 1, Milan, Italy Purpose or Objective Standard 3DCRT after breast conserving surgery (BCS) may cause skin toxicity with a wide range of intensity including acute effects like erythema or late effects. In order to reduce these side effects it is advisable to identify potential factors of influence in breast cancer patients undergoing 3DCRT of the breast and modern systemic therapy Material and Methods breast cancer patients consecutively treated in our institution with 3D-CRT after BCS (50 Gy whole breast photon radiotherapy followed in same cases by 10 OR 16 Gy photon OR electron boost to the tumor bed) were evaluated with special focus on documented skin toxicity during RT course. Acute skin erythema (AE) was visually assessed and recorded using the RTOG scoring system, before RT and every 5 fractions. In this study, grade 2-3 AE during RT was considered as the primary endpoint. A number of relevant clinical risk factors was prospectively recorded: age, skin phototype, smoking habits, use of drugs, neoadjuvant chemotherapy with anthracyclines and/or taxanes and/or trastuzumab, hormone therapy with tamoxifen or aromatase inhibitors, comorbidities and related drugs, T stage, location of breast surgery. Dosimetric feature were extracted from the skin dose- volume histogram for the whole treatment (DVH, absolute volume in cc), with skin defined as the difference between the body contour and a 5mm inner isotropic contour from the body. Dosimetric and clinical variables were included into multivariable logistic regression. Goodness-of-fit was