Session Item

Saturday
May 08
11:40 - 12:40
GEC-ESTRO Best Poster Presentations
Poster presentation
12:00 - 12:10
8-Gy single-fraction HDR brachytherapy boost after WBI on localized breast cancer in young women
PP-0119

Abstract

8-Gy single-fraction HDR brachytherapy boost after WBI on localized breast cancer in young women
Authors:

Alonso La Rosa de los Ríos1, Beatriz Quiles1, Jose Luis Guinot1, Maribel Tortajada1, Miguel Santos1, Alba Montaner2, Alba Sanchez2, Leoncio Arribas1

1Fundación Instituto Valenciano de Oncología (IVO), Radiation Oncology, Valencia, Spain; 2Fundación Instituto Valenciano de Oncología (IVO), Radiophysics, Valencia, Spain

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Purpose or Objective

The primary objective was to evaluate locoregional control survival outcomes in localized breast cancer in young patients treated with a single 8Gy high-dose-rate boost of brachytherapy (HDR-BT) after whole breast irradiation (WBI). The secondary objectives were to determine the short- and long-term adverse effects of the treatment comparing results by risk groups.

Material and Methods

A prospective, single center, analytic study was conducted with 70 patients under 41 years old diagnosed with localized breast cancer treated with breast conserving therapy (free margin lumpectomy and 50Gy WBI) plus 8Gy single-fraction boost of HDR-BT between January 2008 and October 2012.


Results

The study included 70 patients (24.3% under 35yo), with a median age of 37 years old. Invasive  ductal carcinoma was the predominant histology (97.1%) of which 55.7% had a grade 3 of differentiation. At a median follow up of 107 months (8-146); 4 (5.7%) patients locally relapsed; 6 (8.6%) died, 5 due to cancer progression, finally 15 (21.4%) patients progressed to metastatic disease. 8 patients were lost during the follow up. From the total of 70 patients, 16 (22,8%) were categorized as triple negative, 4 (25%) of them were younger than 35 years old, including 2 (50%) who developed local recurrence.

 

The overall survival for 5 and 10 years were 97,1% and 91,4% respectively. Local recurrence survival was 97,1% at 5 years and 94,3% at 10 years. Patient 35 years old or less had higher rate of recurrence compared with the 35 to 40 years old group (17.6% vs 1.9%; p=0.009); difference also seen for overall (88,2% vs 92,5%; p=0,5), disease specific (88,2% vs 94,3%; p=0,3) and metastasis free survival (82,4% vs 90,6%; p=0,3). Stratifying patients by hormone receptor status, we found a tendency, no statically significative, for worst outcomes in patients with the absence of receptors (triple negative); OS (93,8% vs 90,7%; p=0,7), LCS (87,5% vs 96,4%; p=0,2) and MFS (87,5% vs 88,9%; p=0,9). In terms of cosmetic outcomes, it was valuated in 57 patients. 54 (94,7%) had an excellent-good result and 3 patients (5,3%) were classified as bad.


Conclusion

The study showed that 8Gy single-fraction HDR boost after whole breast irradiation was well tolerated. An improved local tumor control with good cosmetic outcomes were observed as well as a low rate of complications. The <35yo subgroup causes special concerns due to the high rate of local recurrence observed, raising the question whether a dose escalation or a less conservative surgery treatment should be considered.