ESTRO 36 Abstract Book

S639 ESTRO 36 _______________________________________________________________________________________________

and was described and graded according to the RTOG classification. Relation to previous acute skin toxicity, clinical and dosimetric factors was assessed by univariate analysis. Results At a median follow up of 54 months (range 50-60), sixteen patients (11%) developed late skin toxicity. Fifteen grade G1-2 (dyschromia and telangiectasia), while 1 patients had nipple necrosis (G4) at the the site of the surgical scar. Interestingly, no significant relation with previous radio- induced acute skin toxicity was found. Conclusion Our study suggests that late radioinduced skin toxicity appears in a small but significant portion of patients treated by BCT and seems to be unrelated to previous acute skin toxicity. EP-1178 Breast radiotherapy without nodal irradiation in pT1-2 pN0-1 stage: prognostic factors and outcomes. C. Di Carlo 1 , M. Nuzzo 1 , L.A. Ursini 1 , M. Trignani 1 , L. Caravatta 1 , G. Di Girolamo 1 , M. Di Nicola 2 , D. Genovesi 1 1 Ospedale Clinicizzato S.S. Annunziata, Radiotherapy, Chieti, Italy 2 Biostatistic laboratory, Clinical Sciences, Chieti, Italy Purpose or Objective The aim of study was to evaluate loco-regional recurrence (LRR), overall survival (OS), disease free survival (DFS), prognostic influence of the number of positive lymph nodes and others variables in treatment of early breast cancer patients. Material and Methods From December 2005 to December 2013, 377 female patients with pT1-T2 pN0-N1 were treated in our Radiotherapy Institute and retrospectively evaluated. All patients received conservative surgery with sentinel- lymph node and/or axillary dissection followed by whole breast radiotherapy. According to our institutional protocol nodal region irradiation was not performed. Four cohorts were analyzed according to the number of involved lymph nodes: N0, N1 n1 (1 lymph node +), N1 n2 (2 lymph nodes +), N1 n3 (3 lymph nodes +). Actuarial rates of total LRR, DFS and OS were calculated by the Kaplan-Meier method. Comparisons of clinical and pathologic characteristics between patients groups were calculated using the log-rank test. Results From a total of 377 patients, 284 patients with pT1 tumors and 93 with pT2 tumors were evaluated. The median age was 58 years (range 31-82 years). The absence of involved lymph nodes has been assessed in 276 patients while N1 was reported in 101 patients: 63 N1 n1 , 19 N1 n2 , and 19 N1 n3 . The median follow-up was 4 years with a LRR rate of 3.4% (13/377). In particular a nodal recurrence rate of 1.06% (4/377) was observed: 2 occurred in the axillary region, 1 in supraclavicular region and 1 within internal mammary chain. Estrogen receptor, menopausal status, adjuvant chemotherapy, Her2neu, margin status and grading were not significantly associated with OS and DFS, whereas progesterone receptors were significantly correlated with DFS and tumor size (T>2 cm) with DFS, LRR and OS. Furthermore, a significant correlation between 3 metastatic lymph nodes and OS was found (N1 n3 p-value 0.024, N1 n1 p-value 0.175, N1 n2 p-value 0.369). Conclusion In our series, adjuvant radiotherapy after breast- conserving surgery led to low rates of LRR and high rates of OS and DFS in pT1-T2 pN0-N1 breast cancer patients. Moreover, although the retrospective design, the limited sample size and given the low rate of nodal recurrence, the results observed from our study seem suggest that nodal irradiation in patients presenting 1-3 positive

axillary nodes could be not necessary to improve outcome.

EP-1179 Target Volume Definition after Lumpectomy for Accelerated Partial Breast Irradiation (APBI) or Boost I.F. Ciernik 1 , A.M. Greiß 2 1 Dessau City Hospital, Radiation Oncology, Dessau, Germany 2 Deaconess Hospital, Department of Surgery, Dessau, Germany Purpose or Objective After tumor resection and surgical manipulation during lumpectomy or oncoplasty, the tumor cavity and the tissue at risk for local relapse is often not clearly definable during radiation therapy planning. Metal clips placed at the thoracic fascia are used to better define the former tumor location. Here we investigated the ability of a liquid tissue marker (BioXmark®, Nanovi®, Copenhagen, DK ) to define the local cavity for the purpose for defining a boost volume or a target volume suitable for APBI. Material and Methods Preclinical investigations how to apply BioXMark® liquid marker best for visualization by computer tomography were performed. Subsequently, thirteen patients underwent lumpectomy for limited stage breast cancer disease and the tumor cavity was marked with the liquid marker as well as a surgical clip. All patients were older than 50 yrs, and all patients presented with hormone- receptor positive disease less than 3 cm, pN0 and all were potentially suitable for APBI. The tumor cavity was marked immediately after resection with BioXmark® and surgical clips. The liquid marker was placed before any oncoplasty-manipulation was performed in three patients analysed. A planning CT was performed 4-5 weeks after surgery. The boost volume was defined, according to the metal clips and the area marked by BioXmark. Results In preclincal studies a phantom was used to see that the liquid marker sprayed over several square centimeters achieved best Imaging qualities on comptuer tomgraphy. Thus, applying a film of liqud marker over the surface of interest was chosen for further clincal investigations. Seven patients were analysed by the time of submission. The tumor cavity was clearly marked for the purpose of tumor cavity segmentation in six out of seven cases. In one patient, the marker was not reliabely discrimiated from the glandular tissue. The mean volume or the tumor bed was 22,69 ml (range 8,1 - 40,96). In respect to the metal clips placed on the thoracic wall after lumpectomy, considerable displacement of the boost target volume after oncoplasty was visualized. Conclusion Visualization of the tumor cavity can improve on the accuracy of the target volume definition for APBI and may allow optimizing PTV margins. Further investigation is justified to reveal clinical utility of liquid-marker- based target volume definition after lumpectomy. EP-1180 Whole breast radiotherapy in Lateral Decubitus position : efficacy and toxicity E. Bronsart 1 , S. Dureau 2 , H. Xu 1 , F. Berger 2 , F. Campana 1 , E. Costa 1 , A. Chilles 1 , A. Fourquet 1 , Y. Kirova 1 1 Institut Curie, Radiation therapy, Paris, France 2 Institut Curie, Biometrics, Paris, France Purpose or Objective To evaluate whole breast 3D conformal radiotherapy (RT) delivered in lateral decubitus position (Isocentric Lateral Dubitus ILD) and report the acute and the late cardiac and pulmonary toxicity of a cohort of patients treated with ILD.