The prognostic influence of neuroendocrine differentiation in breast cancer: results of a long-term follow-up study.

Reports about neuroendocrine (NE) differentiation in breast carcinomas and its possible relation with prognosis are scarce. Furthermore the results of some studies have not been subjected to multivariate survival analysis and the follow-up periods were relatively short. Therefore, in the present long-term follow-up study, the prognostic influence of immunohistochemically defined NE cells, present in the tumours of 40 out of 317 (12.6%) curatively operated breast cancer patients, was studied. The mean follow-up period was 104 months. NE differentiation (NED) was determined by the immunohistochemical detection of chromogranin A and/or synaptophysin. This is concordant with other studies focussing on NED in breast cancer. In contrast to the literature in our series only in 9 out of 40 cases (23%) we were able to detect coexpression of chromogranin A and synaptophysin. This might be due to the characteristics of the antibodies we used. Although most tumours in our series were of the usual type, some tumours with NED were of a special type. Neither univariately, nor taking account of various known prognostic factors, does focal NED appear to carry a special prognostic significance. This finding is in line with results of previous studies.