Although tubular carcinoma (TC) is known to have a favorable prognosis, it is still unknown whether this subtype represents a distinct type of breast carcinoma or whether it behaves like other low-grade luminal A-type breast carcinomas.
In this study, we performed a retrospective analysis of a large well-characterized series of breast cancers (2,608 carcinomas) to assess the clinicopathologic and molecular features and prognostic value of TC compared with grade 1 ductal carcinomas of the breast.
When compared with grade 1 ductal carcinoma (n = 212), TC (n = 102) was more likely to be detected on mammographic screening, had smaller median size, and less frequently showed lymphovascular invasion. Compared with grade 1 ductal carcinoma, TC was associated with longer disease-free survival (chi(2) = 13.25, P < .001) and breast cancer-specific survival (chi(2) = 8.8, P = .003). In this study, none of the patients with TC developed distant metastasis or died from the disease without an intervening recurrence as invasive carcinoma of different histologic type.
We conclude that the biologic behavior of TC is excellent and is more favorable than that of grade 1 ductal carcinoma. Patients with TC may be at risk of developing second primary carcinomas in the contralateral breast, which may be of higher grade and poorer potential prognostic outcome. In addition, patients with TC seem to have a close to normal life expectancy, and as a consequence, adjuvant systemic therapy may not be justified in their routine management.