Oncologic outcomes after breast-conserving surgery with radiotherapy versus mastectomy in patients with Paget's disease of the breast: systematic review and meta-analysis.

Background: The conventional approach to treatment for Paget's disease of the breast has been mastectomy, but there is an increasing trend to consider breast-conserving surgery (BCS) followed by radiotherapy (RT) in these patients. This study aimed to provide an updated systematic review and meta-analysis comparing outcomes after BCS with RT versus mastectomy in the treatment of Paget's disease of the breast.

Methods: Studies before May 2021 were included. Primary outcomes were overall survival and local recurrence. Separate analyses of Paget's disease associated with ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) were undertaken. Meta-regression was used to adjust for imbalance in the proportion of IDC among patients selected to undergo BCS versus mastectomy.

Results: Overall survival in patients with Paget's disease who underwent BCS with RT was higher than for those who underwent mastectomy with pooled mortality hazard ratio (HR) of 0.68, (95% per cent c.i. 0.45 to 1.01). Patients with Paget's disease with DCIS had higher overall survival after BCS with or without RT versus mastectomy, with adjusted HR of 0.14 (0.10 to 0.20) and 0.28 (0.22 to 0.36), respectively. For patients with Paget's disease and IDC, overall survival was lower for BCS with or without RT versus mastectomy, with adjusted HR of 0.84 (0.57 to 1.25) and 1.64 (1.04 to 2.58), respectively. In Paget's disease and IDC, local recurrence risk was much higher for BCS with RT, RR 26.8 (1.60 to 456) versus without RT, RR 51.8 (6.80 to 391). In patients with Paget's disease and DCIS, risk of local recurrence versus mastectomy was lower for BCS with RT 0.72 (0.11 to 4.50) but slightly higher for BCS alone 1.38 (0.09 to 21.20).

Conclusion: BCS with RT may be a comparable treatment alternative to mastectomy for patients with Paget's disease with DCIS, and for selected patients with Paget's disease and IDC.