ESTRO 37 Abstract book

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ESTRO 37

underwent conservative treatment and patients with stage III submitted to mastectomy, followed by adjuvant weekly hypo-fractionated irradiation.The irradiation schedule consisted in 6 fractions of 6.25 or 5 Gy per fraction once a week up to a total dose of 37.5 Gy o 30 Gy, by means of a Cobalt-60 unit and mainly with photons 6 MV of a linear accelerator and conformal 3D planning. A boost of 1 or 2 additional sessions at the same fractionation was administered in case of involvement of the surgical margins. Node areas were treated in case of positive nodes. All patients were evaluated weekly for treatment tolerance and underwent control of acute local toxicity according to the RTOG scale indicating supportive treatment when necessary. Patients were followed periodically after a month, 3 or 6 months and subsequently at least once at a year evaluating chronic toxicity, local and systemic control. Results An amount of 486 consecutive patients have been evaluated. The patients underwent conservative breast surgery in 78.6% of cases, total mastectomy in 20%, biopsy alone in 1.4%. Patients received once-weekly irradiation of 6.25 Gy in 90.7% of the series and 5 Gy in the remaining 9.3% of patients. They received 6 weekly fractions in 80.7% of and a boost was delivered to the tumor bed in 17.5% (1-2 additional sessions). In 1.8% of cases the treatment was uncompleted due to medical conditions. After a median follow-up of 51 months, the overall survival according to the Kaplan-Meier method after 5-year was 74.2% ± 2.3%, the specific survival was 90% ± 1.6%, the local relapse free survival was 96.5% ± 1% and metastasis-free survival was 90% ± 1.6%, Regarding toxicity, 75.6% of the patients had grade I-III acute dermatitis and 30.6% had mild or moderate chronic fibrosis, mainly asymptomatic. Conclusion Due to old patient age in this series the mortality is mainly produced by other diseases than breast cancer, leading to a high specific survival and local control, This weekly schedule leads to a good acute tolerance, the chronic toxicity is mild, allows better compliance of treatment and increases the quality of life in older patients with breast cancer. EP-1301 Incidental or intentional node irradiation in breast cancer. Preliminary results of OPTIMAL Trial. M. Algara 1 , J. López-Guerra 2 , A. Flaquer 3 , I. Beato 4 , F. Martínez 5 , J. Rodríguez 6 , X. Sanz 1 , J. Salinas 7 , M. Soler 8 , A. Frías 9 , G. Juan 10 , A. Manso 11 1 Parc de Salut Mar, Radiation Oncology, Barcelona, Spain 2 Hospital Virgen del Rocío, Radiation Oncology, Sevilla, Spain 3 Hospital Universitario de Araba, Radiation Oncology, Araba, Spain 4 Hospital Provincial de Castellón, Radiation Oncology, Castellón, Spain 5 Hospital Universitari La Fe, Radiation Oncology, Valencia, Spain 6 Hospital Universitario de León, Radiation Oncology, Leon, Spain 7 Hospital General Universitario Santa Lucía, Radiation Oncology, Cartagena, Spain 8 Hospital Universitario de la Ribera, Radiation Oncology, Alzira, Spain 9 Hospital Universitario de Cruces, Radiation Oncology, Barakaldo, Spain 10 Fundación Hospital de Jové, Radiation Oncology, Gijon, Spain 11 Hospital Universitario de la Paz, Radiation Oncology, Madrid, Spain Purpose or Objective To know the doses administrated to lymph node areas in a trial comparing intentional irradiation respect

incidental irradiation in breast cancer, with low burden node involvement demonstrated by a molecular test. Material and Methods The OPTIMAL Trial is designed to show the non-inferiority of incidental irradiation, as compared to intentional irradiation of the auxiliary nodes in terms of 5-year disease-free survival of early breast cancer patients. Inclusion criteria were: patients with node negative early breast cancer, treated with conservative surgery and lymph node involvement tested by means OSNA ( One Step Nucleic Acid Amplification ) and total tumor load between 250-5000 copies (micro-metastasis) or between 5000- 15000 copies (macro-metastasis). Patients were randomized to intentional irradiation to breast and lymph node levels I to III and supraclavicular fossa (arm 1) or incidental irradiation were only treatment directed to breast was allowed (arm 2). In all cases, all lymph node areas and internal mammary chain were contoured, and measures of the dose administered to all contoured volumes were recorded. Patients were treated at standard fractionation of 2 Gy up to 50 Gy and a boost was administered according to guidelines of each participating department. Results More than 300 patients have been included and the first 247 have been analyzed (125 in arm 1 and 122 in arm 2). Patients presented micro-metastasis in 98 and 104 cases, and macro-metastasis in 23 and 14 patients of intentional or incident ghal arm respectively. Both arms were well balanced according to the characteristics of the patients: age, tumor, stage and molecular profile. The mean copies by OSNA in the range of micro-metastases were of 1263 in intentional arm and 1121 in incidental arm. The same values in the range of macro-metastases were 8682 and 7503 in the both arms respectively. There was on local relapse in intentional arm and 2 cases of metastatic spread in the incidental arm. There was no regional relapse in both arms. The mean doses at lymph node in arm 1 was 49.7 Gy at level I, 49.1 at level II, 49.4 Gy at level III, and 48.9 at supraclavicular fossa. The doses for the same node levels in arm 2 were 31.9 Gy, 18.8 Gy, 7.3 Gy and 1.4 Gy respectively. The median doses at internal mammary chain were similar i n both groups (23Gy in arm 1 and 16.7 in arm 2). Conclusion At the moment there are no differences in local control, regional control and metastasis in both arms of the trial. The doses diminish as it increases the level of the lymph nodes in incidental arm. This trial should allow to know what extent of node areas must be irradiated in case of total tumor load in axillary nodes in the range of 250- 15000 copies by the innovative OSNA test. EP-1302 Impact On Cardiovascular And 2nd Tumor Risk From Nodal Rt In Breast Cancer: A Dosimetry Study A. Aranha Pereira Machado 1 , P. Mendes Maia 1 , C.V. Vicente Magiolino 1 , C. De Queioz Tannous 1 , A.C. Pellizon 1 , R.C. Fogarolli 1 , M. Jenwei Chen 1 , M.L. Gobo Silva 1 , D. Guedes de Castro 1 , T. Machado Coelho 1 , H. Ramos 1 , G. Rocha Melo Gondim 1 1 AC Camargo Cancer Center, Radiation Oncology, São Paulo, Brazil Purpose or Objective Irradiation of the internal mammary chain (IMC) and supraclavicular fossa (SF) has oncologic benefits in subgroups of breast cancer patients. Possible late side effects (LSEs), such as 2nd tumors and cardiovascular diseases, are a concern after the Radiotherapy (RT) of nodal chains. Perform the dosimetric analysis of Radiotherapy plans with the inclusion or not of SF and IMC and estimate whether the increase in mean doses (MD) in the heart and lungs with lymph node irradiation may lead to LSEs that may surpass the benefits of this treatment.