The effect of Paget disease on axillary lymph node metastases and survival in invasive ductal carcinoma.

Background: The objective of this study was to examine the effect of Paget disease (PD) on axillary lymph node metastases and survival in patients who had concomitant invasive ductal carcinoma (PD-IDC).

Methods: The Surveillance, Epidemiology, and End Results (SEER) database was used to identify women who were diagnosed with PD-IDC from 2000 to 2011, comparing baseline demographic and tumor characteristics with those who were diagnosed with IDC alone during the same period. Multivariable logistic regression was used to examine the association of PD-IDC with axillary lymph node metastasis, and breast cancer-specific survival and overall survival were compared between the PD-IDC and IDC groups using the Kaplan-Meier method and Cox proportional hazards regression.

Results: The study cohort included 1102 patients with PD-IDC and 302,242 controls with IDC alone. PD-IDC tumors were more likely to be centrally located (26.9% vs 5.5%; P < .001), high grade (63.5% vs 40.3%; P < .001), >2 cm in greatest dimension (47.1% vs 35.7%; P < .001), and estrogen/progesterone receptor-negative (45.2% vs 22.1%; P < .001). In adjusted analyses, patients with PD-IDC had higher odds of axillary lymph node metastasis (odds ratio, 1.83; P < .001). The unadjusted 10-year breast cancer-specific and overall survival rates were lower for the PD-IDC group compared with the IDC-alone group, although, after adjusting for disease stage, tumor characteristics, and local therapy, no significant differences in mortality risk were observed between the 2 groups (hazard ratio, 0.91; P = .24).

Conclusions: PD-IDC is associated with an increased risk of axillary lymph node metastasis, but not with inferior survival, compared with IDC alone after adjustment for other disease factors.