Session Item

Monday
May 09
08:00 - 08:40
Room D1
Modern imaging in radiation oncology
Esther Troost, Germany
3010
Teaching lecture
Clinical
11:15 - 11:25
APBI versus very APBI in the elderly: a comparison analysis of oncological outcome and late toxicity
OC-0014

Abstract

APBI versus very APBI in the elderly: a comparison analysis of oncological outcome and late toxicity
Authors:

Jena-Michel Hannoun-Levi1, Daniel Lam Cham Kee1, Jocelyn Gal2, Renaud Schiappa3, Mathieu Gautier4, Marie-Eve Chand5

1Antoine Lacassagne Cancer Center, Radiation Oncology, Nice, France; 2Antoine Lacassagne Cancer Center, 2. Biostatistic Unit, Nice, France; 3Antoine Lacassagne Cancer Center, Biostatistic Unit, Nice, France; 4Antoine Lacassagen Cancer Center, Radiation Oncology, Nice, France; 5ANtoine Lacassagen Cancer Center, Radiation Oncology, Nice, France

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Purpose or Objective

Accelerated partial breast irradiation (APBI) represents a validated technique for low-risk breast cancer. Recently, very APBI (vAPBI) based on a shorter regimen using less than 5 brachytherapy fractions was described in the literature. We analyzed clinical outcome and late toxicity after APBI or vAPBI in the elderly.

Material and Methods

We compared data from two cohorts of elderly women with low-risk breast cancer treated with APBI based on multicatheter interstitial high-dose rate brachytherapy (MIB). From 2004 to 2012, APBI delivered a total dose of 34 Gy in 10 fractions. From 2013 to 2018, vAPBI delivered a single fraction of 16 Gy. All the patients were censored at 60 months. Five-year oncological outcome comparison was based on local (5y-LRFS), regional (5y-RRFS) and metastatic relapses (5y-MRFS), as well as specific (5y-SS) and overall survival (5y-OS). Late toxicity comparison was investigated. Statistical comparisons were performed using the χ2 or Fisher’s exact test for qualitative data, student test or non-parametric Wilcoxon test for quantitative data and log-rank test for censored data. All p values inferior to 0.05 (two-sided) were considered statistically significant.

Results

From 2004 to 2018, 157 pts were retrospectively analyzed (APBI:109pts vs. vAPBI:48pts). All the patients were enrolled in the APBI program according to the same selection criteria: elderly pts (>70) with low-risk breast cancer. Apart from MFU, no significant differences were noticed between APBI and vAPBI treatment groups: median age was 76 vs. 78y, median tumor size was 10 vs. 10mm, axillary status N0/N1mic was 92 vs. 96. With a MFU of 97 vs. 73 months (p=0.002) for APBI and vAPBI groups respectively, 1 local relapse was observed after APBI while no local relapses were detected after vAPBI. Regarding oncological outcome at 5 years, no significant differences were observed between APBI versus vAPBI groups for LRFS (99 vs. 100%), RRFS (98 vs. 98%), MFS (98 vs. 98%), SS (97 vs. 98%) and OS (91 vs. 90%). The rate of late toxicity (total number of complication) was 55 vs. 67% (p=0.173) for APBI versus vAPBI groups respectively with no G3.

Conclusion

According to our knowledge, this is the first study comparing APBI vs. vAPBI in a well-defined elderly cohort showing equivalent results in terms of oncological outcome and toxicity profile. vAPBI based on a single fraction of MIB represents an attractive option to reach an excellent local control in the elderly with low-risk breast cancer avoiding the burden of conventional/hypofractionnated external beam radiation therapy and the higher risk of local recurrence induced by the avoidance of adjuvant breast irradiation.