For ipsilateral second breast tumor event (2ndIBTE), second conservative treatment
(2ndCT) combining lumpectomy plus accelerated partial breast re-irradiation (APBrI)
represents a curative option. The aim of this study was to analyze oncological prognostic
factors for 2ndIBTE patients treated with 2ndCT.An analysis of clinical practices
was conducted across 7 academic hospitals/cancer centers in 6 European countries based
on the XXXX database. Patients presenting a 2ndIBTE occurring after conservative surgery
(lumpectomy+axillary evaluation) and irradiation performed for the primary tumor,
underwent a 2ndCT with brachytherapy based APBrI. The main outcome was 5-year cumulative
incidence (CI) rate of second local relapse (2ndLR). All analyzed patients were classified
according to risk groups for GEC-ESTRO APBI (APBI) and molecular classification (Mol.)
and time interval between first and second breast surgery (TIS1S2). Finally, we combined
GEC-ESTRO APBI, molecular and TIS1S2 risk groups, leading to the definition of a new
score (named "TAM") specifically designed for 2ndIBTE oncological outcome analysis.From
07/1994 and 01/2021, a total of 508 patients received a 2ndCT. At the time of 2ndIBTE,
median age was 64.6 years [56.2-72.6]. With a median follow-up of 60.9 months [56.2-72.6],
5-year 2ndLR CI rate was 4% [95%CI 2-6]. Five-year distant metastasis disease CI rate
was 7% [95%CI 4-10]. Five-year disease-free and overall survival rates were 89% [95%CI
86-93] and 91% [95%CI 88-94] respectively. In multivariate analysis, TAM score was
an independent prognostic factor for all the oncological items (p<0.001) except disease
specific survival (p=0.07) and overall survival (p=0.09). G≥3 late toxicity rate was
12.1%.This analysis of 2ndCT combining lumpectomy with APBrI for 2ndIBTE confirmed
the excellent oncological results obtained after 2ndCT. Furthermore, GEC-ESTRO TAM
score appears to be an important prognostic factor, assisting patients and physicians
in the decision-making process.
