ESTRO 2021 Abstract Book

S925

ESTRO 2021

Development, Granada, Spain; 4 Laboratorio Inves Biofarm, Clinical Study Coordination, Granada, Spain; 5 University of Granada, Statistics and Operational Research, Granada, Spain

Purpose or Objective Radiation dermatitis (RD) is a common side effect of radiotherapy in breast cancer patients. No definitive guidelines are available for the management of RD, with treatment varying substantially among institutions. The current standard of skin care is the topical application of barrier creams with different formulations that have been developed and tested to prevent, delay and resolve the appearance of this frequent adverse effect. Calendula is extracted from the marigold flower of the Compositae family ( Calendula officinalis ). The bioactive compounds of Calendula may have antioxidant properties and act to enhance re‐epithelialisation. Calendula has been studied in clinical trials for RD, with variable results. The aim of this clinical trial was to compare the efficacy of a new cream formulation with Calendula (case group) versus standard topical treatment at our department (control group) for reducing RD. Materials and Methods A single-centre parallel-group trial was designed ad hoc . Eligible women had to undergo adjuvant radiotherapy treatment after surgery. 65 patients agreed to take part in this study. 6 patients were excluded for various reasons (mastitis, use of unconventional fractionation, use of various creams not recommended by our team), leaving a final sample of 59 patients. Patients were assigned to each group with simple randomization, obtaining 31 patients on the case group (52.5%) and 29 on the control group (47.5%). The presence of RD was assessed two weeks after the end of radiotherapy. RD was graded using CTCAE criteria v5.0. Furthermore, we analyzed the need to add other topical treatments (dressings or corticosteroid creams). Results 69.5% had mild erythema or dry peeling (61.3% case group vs. 78.6% control group), 27.1% had moderate erythema or wet peeling (32.3% vs. 21.4%) and 3.4% developed wet desquamation in other areas or bleeding (6.5% vs. 0%); obtaining that there was no statistically significative difference between both groups (χ2 = 3.075; p = 0.215). We analyzed the need to add dressings or topical corticosteroids as treatment. 13 women (22%) needed these treatments: 7 (22.6%) patients in the case group and 6 (21.4%) in the control group. As result, there was no statistically significative difference between both groups (χ2 = 0.011; p = 0.915) with an odds ratio of 1.069 in favour of the Calendula group [0.311-3.675]. Conclusion Given the findings of this study, the probability of having RD was 1.069 higher in the case group, being this difference not statistically significative. Calendula appears to be a useful topical therapy in the treatment and prevention of radiation-induced skin- toxicity; however, the evidence for its use remains weak. It is necessary to conduct a clinic assay with a larger number of patients to confirm the inclusion of this new formulation as an option for the RD treatment. PO-1112 Repeated courses of RT in breast cancer patients as salvage therapy for recurrent brain metastases A. Di Donato 1 , A. Iurato 1 , E. Ippolito 1 , F. Pantano 2 , P. Matteucci 1 , M. Fiore 1 , G. Tonini 2 , S. Ramella 1 1 Campus Bio-Medico di Roma, Radioterapia Oncologica, Roma, Italy; 2 Campus Bio-Medico di Roma, Oncologia Medica, Roma, Italy Purpose or Objective Brain metastases (BM) may affect up to 30 % of patients with advanced breast cancer. The incidence is rising with more effective systemic agents and brain recurrence may develop despite stable extracranial disease. The aim of this study was to evaluate the impact of sequential repeated courses of radiotherapy (RT) in breast cancer patients with oligoprogressive isolated BM. Materials and Methods A cohort of consecutive patients with breast BM treated with stereotactic fractionated RT (SFR) were retrospectively identified from institutional databases. Patients with isolated recurrent BM after a first course of RT (either WBRT or SFR) were identified. Brain progression-free survival (BPFS) and Overall Survival (OS) rates from the diagnosis of BM were calculated from the date of first radiotherapy treatment using the Kaplan- Meier method. Results 68 patients with 161 BM treated with SFR were included in this analysis. Median age was 62 years (35-86). 7% of this population was Luminal A, 37% was Luminal B, 30 % HER2 positive, 10% triple negative and 16% not determined. Thirty patients (44.1%) received more than one radiotherapy course. Eighteen patients (26.5%) received SFR after whole-brain radiotherapy (WBRT). Twelve patients (17.6%) received more than one SFR course (5 patients 2 courses, 6 patients 3 courses and 1 patient 4 courses) for a total of 25 new BM treated. Median dose of repeated SFR was 27 Gy (range 12-45). Median BPFS after first course of RT was 7.9 months (IC 95% 10-41 months) and 7.6 months (IC 95% 1-15 months) after 2 courses. For the entire cohort of patients 1-2 year OS from the diagnosis of BM was 82.1% and 72.8% respectively. For patients who received more than one course of RT the 1-2 year OS was 85.7% and 76.2% (p=NS). Conclusion Patients affected by breast cancer BM may experience long survival rates, mainly due to extracranial disease control achieved with new drugs. Therefore more than one course of RT may be needed in these patients presenting with oligoprogressive brain disease. Repeated courses of SFR represent a reasonable and feasible treatment option.