OUTCOME OF CONSERVATIVE THERAPY FOR INVASIVE BREAST-CANCER BY HISTOLOGIC SUBTYPE

Between 1977 and 1986, 879 patients with Stage I and II breast cancer underwent excisional biopsy, axillary dissection, and radiation. Median follow-up was 61 months (range 2-159 months). The patients were divided into seven groups based on histologic subtype: (a) 368 patients with both infiltrating and intraductal ductal carcinoma, (b) 389 infiltrating ductal carcinoma, (c) 41 infiltrating lobular carcinoma, (d) 23 combined infiltrating ductal and lobular carcinoma, (e) 28 medullary carcinomas, (f) 12 colloid carcinomas, and (g) 18 tubular carcinomas. Significant differences in clinical T status, pathologic nodal involvement, administration of chemotherapy, estrogen receptor positivity, progesterone receptor positivity, and age were observed between some histologic subgroups. Tubular and colloid carcinomas were more likely to present with T1 lesions, hormone receptor positivity, and node negative status than the other histologic subtypes. Most medullary carcinomas were hormone receptor negative and were younger than 50 years old. Infiltrating lobular carcinoma patients were more frequently lymph node negative, older, node negative, and estrogen receptor positive compared to the other groups (except for tubular and colloid patients). Differences in the administration of chemotherapy primarily reflected differences in lymph node involvement. Location of the tumor in the breast and menopausal status did not correlate with histologic subtype. There were no significant differences in 5-year actuarial overall survival cause-specific survival or relapse-free survival between the histologic categories. In addition, patterns of first failure were not significantly different among the histologic groups in terms of local-only first failure, any local component of first failure, regional-only first failure, or any regional component of first failure. There was, however, a difference among the seven groups in distant metastasis-only at first failure with invasive ductal carcinomas having the highest rate. Despite this difference, histologic subtype had no impact on survival. The site of in-breast failure relative to the location of the original tumor was not significantly different between groups. The histologic subtype of invasive breast cancer is not an independent risk factor in predicting survival or pattern of failure. Conservative surgery and radiation therapy is effective treatment of ductal, lobular, medullary, colloid, and tubular invasive breast cancer.