Paget's disease as a local recurrence after nipple-sparing mastectomy: clinical presentation, treatment, outcome, and risk factor analysis.

Background: Paget's disease is a rare clinical and histological type of local recurrence (LR) after breast cancer treatment both in case of conservative surgery or nipple-sparing mastectomy (NSM) with or without intraoperative radiation.

Methods: We performed an analysis of 861 NSM with electron beam intraoperative radiotherapy (ELIOT) patients treated at the European Institute of Oncology from 2002 to 2008, focused on Paget's disease local recurrence.

Results: In 861 patients (713 invasive carcinoma and 148 intraepithelial neoplasia), there were 36 local recurrences (4.18%), and among these were 7 Paget's disease local recurrences (0.8%). Median follow-up was 50 months. Four cases presented with nipple areola complex (NAC) erosions, two crusted lesions, and one ulcerated NAC. The average latency period from the NSM to Paget's disease local recurrence is 32 months (range, 12-49). Complete NAC removal was performed in all seven recurrences. The average follow-up after NAC removal was 47.4 months (range, 20-78). We found neither locoregional relapse nor metastatic event in this group. All patients were alive without disease.

Conclusions: Paget's disease local recurrence can be found in a significant proportion after NSM. Any suspicious lesion on NAC requires prompt pathological confirmation. Primary carcinoma with ductal intraepithelial neoplasia or invasive ductal carcinoma with extensive in situ component, negative hormonal receptor, high pathological grade, overexpression of HER2/neu, and "HER2 positive (nonluminal)" subtype tend to be significantly associated with more Paget's disease local recurrence and should be followed carefully.