Importance of estrogen receptors for the behavior of invasive micropapillary carcinoma of the breast. Review of 68 cases with follow-up of 54.

The aggressiveness of invasive micropapillary carcinomas of the breast (MPCa) is still controversially discussed. Therefore, we investigated a total of 68 cases and studied the evolution of 54. MPCa were frequently well-differentiated cancers with the following positivities for immunohistochemistry: 74.5% estrogen receptor (ER+), 46.3% progesterone receptor (PR+), 66% Bcl2+, and 36.4% C-erbB-2+. However, in 90.5% of the cases lymph nodes were involved at diagnosis, and 70.6% of T1 tumors showed wide metastatic spread. After a mean follow-up of 52.6 months, 55.6% of the patients were disease free (DF), 7.4% had disseminated disease and 37% had died. Univariate analysis showed significant differences. Thus, the DF group of patients included 90% of those having tumors with an associated colloid pattern, 73.3% of the ER positive tumors, none of the C-erbB-2 positive tumors, and 100% of the tumors with no axillary metastasis, 77.8% of those with metastasis to up to 3 nodes, and 47.2% of those metastasizing to 4 or more nodes. However, using Cox's regression model for survival analysis, ER was the only factor associated with duration of survival (p = 0.0175). In conclusion, although long-term survival in MPCa is determined by involvement of lymph nodes, as is the case in any other breast cancer type, their short-term evolution is influenced by other factors, mostly by estrogen receptors.