Clinical-Pathologic Features and Long-Term Outcomes of Tubular Carcinoma of the Breast Compared With Invasive Ductal Carcinoma Treated With Breast Conservation Therapy

Purpose: To evaluate our institutional experience of treating tubular carcinoma of the breast (TC) and invasive ductal carcinoma (IDC) with conservative surgery and radiation therapy, to compare clinical-pathologic features and long-term outcomes. Methods and Materials: A review of our institution's tumor registry from 1975 to 2007, followed by a central pathology review of available slides, yielded 71 cases of Stage I/II TC and 2,238 cases of Stage I/II IDC treated with breast conservation therapy. Clinical-pathologic features and outcomes were analyzed by subtype to detect significant differences. Results: The median follow-up was 7 years. The TC cohort presented more frequently with pT1 disease (97% vs. 80%, p = 0.0007), pN0 disease (95% vs. 74%, p = 0.0004), hormone-receptor positivity (ER+, 89% vs. 62%, p = 0.0001; PR+, 81% vs. 52%, p = 0.0001), and HER-2 negativity (89% vs. 71%, p = 0.04). Clinical outcomes also favored the TC cohort, with lower rates of breast cancer-related death (1% vs. 10%; p = 0.0109) and distant metastasis (1% vs. 13%; p = 0.0028) and higher rates of 10-year overall (90% vs. 80%; p = 0.033), cause-specific (99% vs. 86%; p = 0.011), and disease-free (99% vs. 82%; p = 0.003) survival. There was a nonsignificant trend toward improved breast cancer relapse-free survival for the TC cohort (95% vs. 87%; p = 0.062) but no difference in nodal relapse-free survival or contralateral breast cancer relapse-free survival (all p values >0.05) between the cohorts. Conclusion: Our institutional experience suggests that TC, when compared with IDC, is associated with more favorable clinical-pathologic features and comparable, if not superior, outcomes after breast conservation therapy, suggesting the appropriateness of a conservative approach to this rare subtype.