Breast ductal carcinoma in situ with microinvasion: Pathological review and clinical implications [Carcinome canalaire in situ avec micro-invasion: Spécificités anatomopathologiques et implications cliniques]

摘要

Purpose: Recent improvements in the detection of breast cancer at an early stage have resulted in a rising incidence of breast ductal carcinoma in situ with microinvasion. So far, there is no consensus regarding its optimal management. We hereby report on our 10-year single institutional experience in breast ductal carcinoma in situ with microinvasion including pathological reviewing. Patients and methods: All consecutive patients treated for a ductal carcinoma in situ with microinvasion at the Institut Claudius-Regaud (Toulouse, France) over a 10-year period were included in this study. We reviewed all available histological materials. Results: Sixty-three patients were eligible for this study. Two patients presented with a lymph node invasion at diagnosis. Each patient benefited from initial surgical management, which consisted either in mastectomy (n= 25) or conservative resection (n= 37). Axillary exploration was performed in 52 patients (82%). After a median follow-up of 61.3 months [46.9;69], the 5-year overall survival and disease free survival were 98.2 (95% CI. = [88.2;99.7]) and 89.5% (95% CI. = [76.3;95.6]) respectively. Two delayed invasive relapses occurred leading to one specific death. The pathological review highlighted a trend towards a loss of HR and HER2 expression (9%) in the microinvasive component in comparison with its surrounded in situ carcinoma. Conclusion: The risk of initial lymph node involvement and delayed invasive local relapse deserve an optimal locoregional management including lymph node evaluation. The non-negligible discrepancy's rate between in situ and microinvasive components justifies HR status and HER2 expression assessment on the microinvasive component.