Paget's disease of the breast: Accuracy of preoperative assessment

Background: Routine preoperative assessment may not accurately assess the extent of underlying cancer in patients with Paget's disease (PD) of the breast. We performed this study to correlate findings on clinical examination and mammography with pathologic results and outcomes in women with PD. Methods: An IRB-approved retrospective review identified all patients with PD between 1975 and 2000. Clinical exam and mammographic findings were recorded, and information on recurrence and survival was obtained from medical records. Results: Univariate analyses identified palpable mass and suspicious mammogram as risk factors significantly associated with a worse outcome. Patients were therefore categorized by combinations of these two preoperative factors. All patients with a palpable mass and a suspicious mammogram had invasive cancer. In the subgroup of 40 women with a benign mammogram and no palpable mass, invasive cancer occurred in 5% and the majority (68%) had ductal carcinoma in situ which extended beyond the nipple. Women with a palpable mass and a suspicious mammogram had significantly worse survival compared to those with a benign mammogram and no palpable mass (P = 0.008). With a median follow-up of 6.4 years, five local recurrences occurred in patients with invasive cancer who underwent mastectomy. Conclusion: In women with PD, a palpable mass or suspicious mammogram portends a high likelihood of invasive cancer. Underlying cancer is common even in women with a benign mammogram and no palpable mass. Although breast conservation is an attractive option in patients with PD, mammography and physical exam may significantly underestimate the presence and extent of underlying disease.