Breast carcinoma developing in patients on hormone replacement therapy: a histological and immunohistological study

Aim-To study the histopathological features of breast carcinoma developing in postmenopausal patients on hormone replacement therapy (HRT). Methods-The sample comprised 60 patients with invasive breast carcinoma inc luding 31 who had received HRT at or shortly before presentation, and 29 wh o had not. Details concerning their tumour size, histological type and grad e, lymph node status, and oestrogen and progesterone receptor status were c ompared. Immunoperoxidase staining for Bcl-2, p53, and E-cadherin was carri ed out on paraffin sections of all 60 patients. The results were then stati stically analysed. Results-Tumours detected in HRT patients were significantly smaller (mean 1 7 mm v 25 mm; p = 0.0156) and of a lower histological grade (p = 0.0414) th an those detected in non-HRT patients. The incidence of invasive lobular ca rcinoma was slightly higher in HRT patients (19% v 14%). Immunohistological ly, 87% of HRT tumours were Bcl-2 positive (compared with 79% in the contro l group), 29% were p53 positive (45% in the control), and 48% were E-cadher in positive (72% in the control group). Although the differences were not s tatistically significant there was a trend towards higher incidence of p53 negative and E-cadherin negative tumours in HRT patients. Conclusions Breast carcinomas detected in patients on HRT have a significan tly higher incidence of two favourable prognostic features (small size and a low histological grade). They also show a trend, statistically not signif icant, of being p53 negative and E-cadherin negative; this may be related t o the slightly higher incidence of invasive lobular tumours in these patien ts.