ESTRO 36 Abstract Book

S625 ESTRO 36 _______________________________________________________________________________________________

Conclusion The rate of SP referral and the use of meds were higher in USA cohort versus the cohort from south of Europe. The reasons for these differences might be related to social and cultural differences, rather than availability of medications. EP-1149 Omission of completion axillary lymph node dissection in patients underrepresented in ACOSOG Z11 B. Gebhardt 1 , Z. Horne 1 , G. Ahrendt 2 , E. Diego 2 , S. Beriwal 1 1 University of Pittsburgh Cancer Institute, Radiation Oncology, Pittsburgh, USA 2 University of Pittsburgh Cancer Institute, Surgical Oncology, Pittsburgh, USA Purpose or Objective ACOSOG Z0011 demonstrated that axillary lymph node dissection (ALND) can be omitted in patients (pts) managed with breast conserving surgery (BCS) and 1-2 positive sentinel nodes (SLN) without adverse effects on loco-regional control (LRC) or survival. Adjuvant radiotherapy (RT) fields in this trial were heterogeneous and included high tangents in half of pts and a 3 rd nodal- directed field in one-third of pts. Most pts enrolled in Z11 were post-menopausal with hormone receptor positive breast cancer and axillary micrometastases. We investigated breast cancer ptswith clinicopathologic features underrepresented Z11 and analyzed RT patterns We retrospectively reviewed the records of pts who underwent BCS with positive SLNS but not undergoing ALND and who completed adjuvant RT. Eligible patients had T3 tumors, >2 positive SLNs, invasive lobular carcinoma, triple negative receptor status, extracapsular extension (ECE), positive surgical margins, Nottingham Grade 3, or age <50 years. Binary logistic regression was used to examine association of pt characteristics with delivered RT fields. Disease-free survival (DFS) and LRC were assessed using the Kaplan-Meier method and log-rank test for association with risk factors. Results We identified 106 pts treated from July 2011 to July 2016. The median follow-up among living pts was 28 (range, 1- 62) months. Nineteen (17.9%) pts were treated with whole-breast irradiation only, and 87 (82.1%) were treated with modified tangential fields covering axillary level I/II. Thirty-four (32.1%) pts received comprehensive nodal RT including a 3 rd supraclavicular (SCV) field. Fifty-two (49.1%) pts received adjuvant chemotherapy. There were 43 (41%) pts with ECE and 43 (41%) with Grade 3 disease. Complete patient characteristics are included in Table 1 . There were trends toward significance with use of a 3 rd SCV field and pN1a disease (p=0.062), increased tumor size (p=0.062), and positive ECE (p=0.077). The overall rates of 2-year DFS and LRC were 95.1% and 98.9%, respectively. One patient experienced an internal mammary nodal recurrence, 1 contralateral breast tumor, and 2 distant metastases. There were no axillary or ipsilateral breast tumor recurrences. Factors associated with decreased DFS on univariate analysis include Grade 3 disease (p=0.021) and use of a SCV field (p=0.008). and clinical outcomes. Material and Methods

Conclusion This retrospective analysis of pts undergoing BCS and SLN biopsy with positive SLNs included pts who were underrepresented or excluded from the Z11 trial yet demonstrated comparable rates of LRC and DFS. Nottingham Grade 3 disease and use of a 3 rd SCV field were associated with decreased DFS, though the apparent detrimental effect of SCV treatment was likely due to greater adverse risk factors causing pts to be selected for more intensive treatment. The high rates of LRC and DFS suggest that completion ALND may be safely omitted in this patient population, though prospective data is needed to confirm this finding. EP-1150 Preliminary results of Intra-Operative RadioTherapy in old women with good prognostic features S. Guillerm 1 , E. Bourstyn 2 , R. Itti 1 , I. Fumagalli 1 , V. Martin 1 , L. Cahen-Doidy 2 , L. Quero 1 , S. Giacchetti 2 , C. Cuvier 2 , M. Espié 2 , C. Hennequin 1 1 Hôpital Saint-Louis, Department of Radiation Oncolgy, Paris, France 2 Hôpital Saint-Louis, Breast Cancer Unit, Paris, France Purpose or Objective In women > 65 yrs with good prognostic features (Isolated tumour <3 cm, infiltrative ductal carcinoma (IDC), presence of Estrogen Receptors ER+, pN0), adjuvant RT increases the local control but do not improve overall survival 1 . One possible alternative is to perform RT during surgery to minimize patient’s travels and cost. 1 Hughes, JCO 2013; 31:2382-2387; Kunkler, Lancet Oncol 2015; 16: 266–73 Material and Methods we reviewed our experience with Intra-Operative RadioTherapy (IORT) for this population. All patients had histologically confirmed breast cancer before surgery and were judged eligible for IORT (Isolated IDC less than 3 cm, ER+). Surgery consisted in sentinel lymph node dissection (SNLD) with intraoperative touch imprint cytology and lumpectomy. IORT was performed only in case of negative SLND. It consisted in a radiation dose of 20 Gy delivered with 50 kV photons (Intrabeam®, Zeiss). Results Between October 2012 and February 2015, 76 pts with pre- operative good prognostic features were planned to have IORT. Seven pts did not have it (positive SNLD: 4pts; multifocality: 3pts). For the remaining 69 pts, characteristics were: mean age: 78yrs [67-96]; mean pT size: 15 mm [3-30]; OMS performance status 0-1: 65pts (94%); Charlson Age-Comorbidity Index: Mean: 4.5 [2-9]. Mean duration of hospitalization was 2.5 days [0-6]. Grade 2 post-operative complications occurred in 19 pts (27%): Abscess: 3pts; Hematoma: 3pts; Seroma: 2pts; Radiation epithelitis: 10pts. Delay in healing was observed in 6 pts. Adjuvant external beam RT after IORT was performed in 3 pts (SNLD+: 2pts; positive margins: 1pt). Hormonal treatment was prescribed in 53 pts (77%). Minimal and mean follow-up were 1 yr and 2 yr, respectively. No local relapse occurred. Two pts died of intercurrent disease. Cosmetic result was assessed in 60pts: excellent: 30pts; good: 28pts; poor: 2pts. Cytosteatonecrosis and cutaneous pigmentation were observed in 7 and 6 pts, respectively. Conclusion IORT in old women is feasible without increasing the rate of post-operative complications. Preliminary results are excellent in terms of local control and cosmesis.