ESTRO 37 Abstract book

S201

ESTRO 37

whole breast irradiation (WBI). Brachytherapy was performed less than 1 month from the end of EBRT. Intravenous sedation, analgesia and local anesthesia was applied to the skin at the area of entrance and exit of the needles. The contour of CTV was decided by clinical assessment, no CT planning was used. All of them were treated with high-dose-rate (HDR) brachytherapy boost with 3 fractions of 4.4Gy to 85% isodose in 24 hours, with rigid needles. Patients stayed one night in the hospital with the implantation. Median age was 61 (Range 37-79). Survival was calculated by Kaplan Meyer method. Results With a median follow-up of 91 months (range 8-240), there have been three recurrences, in postmenopausal women with positive margin. Actuarial ipsilateral breast tumor recurrence (IBTR) at 5 and 10 years was 2.4% and 13.5% in the whole group. In 22 cases with positive margin IBTR was 5.9% and 24.5% at 5 and 10%, and there were no failures in the group of 25 cases with close margin ≤2mm and 7 cases with margin >2mm <5mm (p: 0.087). No IBTR appeared in 9 women aged 50 or younger. One case of recurrence developed an invasive ductal carcinoma and bone metastasis one year later. Long-term fibrosis or induration were registered in 27.8% and telangiectasia in 1.8%. Cosmetic outcome was considered excellent or good in 93.3%. Mastectomy was the salvage treatment for the three cases of recurrence, therefore the long-term breast preservation was 94.4%. Conclusion The treatment of patients with DCIS with positive surgical margin uses to be re-exeresis, but, if rejected, there is an alternative treatment, involving WBI plus HDR-BT boost to the tumor bed. In cases of DCIS with close margin, this approach achieves a 100% of local control at ten years. OC-0399 Accelerated partial breast irradiation in the elderly: a single fraction of HDR brachytherapy R. Kinj 1 , M.E. Chand 1 , J. Gal 1 , M. Gautier 1 , L. Montagne 1 , D. Lam Cham Kee 1 , J.M. Hannoun Lévi 1 1 Centre Antoine Lacassagne, Radiation Oncology Department, Nice, France Purpose or Objective To analyze the clinical outcome of elderly women with early breast cancer who underwent accelerated partial breast irradiation (APBI) based on a post-operative single fraction of multicatheter interstitial high dose –rate A monocentric retrospective cohort study was performed focusing on elderly patients (≥65 years old) presenting a low-risk breast carcinoma treated by lumpectomy plus axillary evaluation followed by a single fraction of MIB APBI. Vectors (Sharp Needles™; Elekta AB, Stockholm, Sweden) were placed mainly intra-operativelyby the radiation oncologist using 1 to 3 planes in respect with the Paris system recommendations. A post implant-CT was performed allowing CTV delineation and dose distribution optimization (OncentraBrachy®;Elekta, Sweden).A single fraction of 16 Gy was prescribed on the 100% isodose.Patients were followed every 4 months during the first year, then twice a year. Oncologic outcome at 3 years was reported based on local relapse free survival (3-y LRFS), specific survival (SS) and overall survival (OS). Acute (<180 days after APBI) and late toxicity were evaluated (Common Terminology Criteria for Adverse Event v4.03).Cosmetic results were evaluated clinically by the physician. Results Between January 2012 and August 2015, 50 women (53 lesions) were treated. Median age was 77.5 (range: 65.2- 92.3) years with a median tumor size of 10 mm (range: 3- 32). Six pts presented an axillary lymph node involvement (4 Nmic, 2 N1). Invasive ductal carcinoma was the most brachytherapy (MIB). Material and Methods

Proffered Papers: BT 4 - Brachytherapy rectum and breast

OC-0397 Single Institute Experience of HDR Intraluminal brachytherapy for rectal cancers with chemoradiation M. Rafi 1 , B. Intakhab 1 , S. Ahmed 1 , S. Rashid ul Ameen 1 , A. Maqbool 1 , A. Shehzad 1 , G. Sultan 1 , R. Mohsin 1 , A. Hashmi 1 , S. Adeeb ul hasan rizvi 1 1 Sindh Institute of urology and Transplantation SIUT, Radiation Oncology, Karachi, Pakistan Purpose or Objective Objective: To determine the feasibility and safety of high dose rate intraluminal brachytherapy (HDR-ILBT) boost during preoperative chemo-radiation for rectal cancer. Material and Methods Patients referred to our department between 2008 and 2013 were selected when they met the eligibility criteria. total of 150 patients were included in this study. patients with locally advanced rectal cancer (≥ T3 or N+), were treated initially with concurrent capecitabine (825 mg/m2 oral twice daily) and pelvic external beam radiotherapy (EBRT) (45 Gy in 25 fractions), then were randomized to group A; HDR ILBT group (n = 75) to receive 5.5-7 Gy × 2 to gross tumor volume (GTV) and group B; EBRT group (n = 75) to receive 5.4 Gy × 3 fractions to GTV with EBRT. All patients underwent total mesorectal excision Results Grade 3 acute toxicities were registered in 53 patients in group A and 32 in group B. Complete pathologic response of T stage (ypT0) in group A was registered in 44 patients and in group B, 12 patients had ypT0 (P < 0.001). Sphincter preservation was reported in 26/40 patients in group A and in 20/40 patients in group B (P < 0.01). Overall radiological response was 68.75% and 66.24% in Group A and B, respectively. During a median follow up of 36 months, late grade 1 and 2 sequelae were registered in 13 patients and 16 patients in the groups A and B, respectively. HDR-ILBT was found to be effective dose escalation technique in preoperative chemo radiation for rectal cancers, with higher response rates, down staging and with manageable acute toxicities. Conclusion High dose rate intraluminal brachytherapy was found to be more convenient, had satisfactory response rates and can be safely used as a tool to boost the gross tumor volume during preoperative chemoradiation. OC-0398 HDR brachytherapy boost for ductal carcinoma in situ of the breast with close or positive margins F. Gines 1 , M. Santos 1 , J.L. Guinot 1 , A. Moreno 1 , J. Fernandez 1 , M. Peña 1 , C. Boso 2 , M. Tortajada 1 , L. Arribas 1 1 Fundación Instituto Valenciano de Oncologia, Department of Radiation Oncology, Valencia, Spain 2 Fundación Instituto Valenciano de Oncologia, Department of Radiation Physics, Valencia, Spain Purpose or Objective To evaluate the influence of a high dose rate brachytherapy (HDR-BT) boost in women who showed close or positive margins after conserving surgery for Ductal Carcinoma In Situ (DCIS) of the breast. Recurrence rates have been associated with the width of the tumor- free margin and it is considered the most important predictor of local recurrence in DCIS. Material and Methods From July 1997 to February 2017, 54 women with DCIS of the breast with less than 5 mm or positive surgical margins were treated with adjuvant 50 Gy standard