Tubular carcinoma of the breast: a population-based study of nodal metastases at presentation and of patterns of relapse.

Tubular carcinoma of the breast (TCB) is a recognized histologic variant of infiltrating ductal carcinoma (IDC) and has been considered to have a comparatively favorable prognosis. However, previous studies have been based on small numbers of cases, some pure TCB and some mixed histology, or have not employed an appropriate comparison group. In this study 171 pure TCB cases and a comparison group of 386 cases with grade I (well differentiated) IDC were identified in a population-based database maintained by the British Columbia Cancer Agency (BCCA). The proportion of cases with axillary nodal involvement at presentation was lower in TCB cases than in the grade I IDC comparison group (12.9% and 23.9%, respectively; p < 0.05). Low-risk tumors (T1 and without vascular lymphatic or perineural invasion) were more prevalent in the TCB patients than in the grade I IDC patients (66.7% and 60.0%; p < 0.05). Low-risk TCB cases had a significantly lower rate of nodal metastases at presentation than low-risk grade I IDC cases (7.0% and 13.2%; p < 0.05). Kaplan-Meier and log-rank analyses indicated a statistically significantly lower rate of local recurrence in TCB cases than among IDC cases (p < 0.05) and a trend toward a lower rate of systemic relapse in TCB cases (p = 0.07). However, no difference in disease-specific survival was observed between TCB cases and grade I IDC comparisons. We conclude that the biologic behavior of TCB was more favorable than that of a comparison group of IDC cases. In view of the low incidence of axillary node metastases at presentation in the low-risk TCB subset (7%), axillary dissection may be omitted as part of the initial surgical management in these patients.