Are prognostic factors for local control of breast cancer treated by primary radiotherapy significant for patients treated by mastectomy?

Recent follow-up studies of patients with mammary carcinoma treated with breast-conserving primary radiotherapy identified a triad of pathologic features significantly associated with local treatment failure. These unfavorable characteristics of the primary tumor were: poor or undifferentiated nuclear grade; intraductal carcinoma within the tumor mass; and intraductal carcinoma in breast tissue outside the perimeter of the primary lesion. The current study was undertaken to assess the impact of these same factors on the prognosis of 573 consecutively treated women, with invasive duct carcinomas 5 cm or less in diameter, and who underwent mastectomy. Histologic sections of all primary tumors were reviewed, and the lesions were classified according to the distribution of intraductal carcinoma present: only within the tumor (IN, 247 cases, 43%), only outside the tumor (OUT, 25 cases, 4%), within the outside (IN-OUT, 158 cases, 28%), or not seen (IFDC, 143 cases, 25%). The median follow-up period for the entire series was 56 months. Ninety-five (17%) patients were dead of disease (median time to death, 36 months). Variables that proved to be statistically significant for overall survival were nodal status (P less than 0.001), nuclear grade (P less than 0.03), and histologic grade (P less than 0.007). Nodal status (P less than 0.001), histologic grade (P less than 0.001), and tumor size (P = 0.01) were significant predictors of disease-free survival. The pattern of intraductal carcinoma, when present, was not predictive of the risk for recurrence or survival in women treated by mastectomy. These findings provide a rationale for additional surgical treatment for women whose tumors have features more likely to be associated with local failure following primary radiotherapy. To permit more detailed pathologic examination of the primary lesion, the initial excision should be carried out separately from the treatment when limited resection and radiation are to be considered as a treatment option.