Conservative management of Paget disease of the breast with radiotherapy: 10- and 15-year results.

BACKGROUND At 5-year follow-up, patients with Paget disease of the breast who were treated with breast-conserving surgery (BCS) and radiotherapy (RT) had excellent results. The current report provides 10- and 15-year rates of tumor control in the breast, as well as disease-free and overall survival rates following BCS and RT in a cohort of patients with Paget disease presenting without a palpable mass or mammographic density. METHODS Through a collaborative review of patients treated with BCS and RT from seven institutions, 38 cases of Paget disease of the breast presenting without a palpable mass or mammographic density were identified. All patients had pathologic confirmation of typical Paget cells at time of diagnosis. Thirty-six of 38 patients had a minimum follow-up greater than 12 months and constitute the study cohort. Ninety-four percent of patients underwent complete or partial excision of the nipple-areola complex and all patients received a median external beam irradiation dose of 50 Gy (range, 45-54 Gy) to the whole breast. Ninety-seven percent of patients also received a boost to the remaining nipple or tumor bed, a median total dose of 61.5 Gy (range, 50.4-70 Gy). RESULTS With median follow-up of 113 months (range, 18-257 months), 4 of 36 patients (11%) developed a first recurrence of disease in the treated breast only. Two of the four recurrences in the breast were ductal carcinoma in situ (DCIS) only and two were invasive with DCIS. Two additional patients had a recurrence in the breast as a component of first failure. Actuarial local control rates for the breast as the only site of first recurrence were 91% at 5 years (95% confidence interval [CI], 80-100%) and 87% (95% CI, 75-99%) at both 10 and 15 years. Actuarial local control rates for breast recurrence, as a component of first failure, were 91% (95% CI, 80-100%), 83% (95% CI, 69-97%), and 76% (95% CI, 58-94%) at 5, 10, and 15 years, respectively. No clinical factors were identified as significant predictors for breast recurrence. Five-, 10- and 15-year actuarial rates for survival without disease of 97% (95% CI, 90-100%) and 5-, 10-, and 15-year actuarial rates of overall survival of 93% (95% CI, 84-100%) at 5 years and 90% (95% CI, 78-100%) at 10 and 15 years were reported. CONCLUSIONS These data confirm excellent rates of local control, disease-free survival, and overall survival at 10 and 15 years following BCS and RT for Paget disease of the breast. This study continues to support the recommendation of local excision and definitive breast irradiation as an alternative to mastectomy in the treatment of patients with Paget disease presenting without a palpable mass or mammographic density.