Oestrogen receptor status of primary breast carcinomas and their metastases. Relation to pattern of spread and survival after recurrence.

Immunohistochemical antibody techniques for detection of oestrogen receptors (ER) were applied to formalin fixed, paraffin embedded sections from 62 primary breast cancers, the metastases of their original regional lymph nodes (29 cases), bone marrow carcinosis (43 cases) and liver metastases (20 cases). Forty per cent of the primary tumours and 31% of the regional lymph node metastases were ER positive; in contrast, less than 20% of liver and bone marrow metastases were ER positive. The ER status of regional lymph node metastases was concordant with that of the primary tumour in 90% of the cases. The concordance rate was 75% for liver metastases and 58% for bone metastases. Patients with ER positive primary tumours had recurrence significantly more often in bone; ER negative tumours recurred more often in the liver. The survival after recurrence (SAR) was significantly related to the ER status of the primary tumour and to that of the regional lymph node metastases. In contrast, the SAR was not associated with the ER status of bone marrow carcinosis or liver metastases. Cox analyses showed that age and ER status of the primary tumour were the most important independent prognostic factors compared to other clinical, therapeutic, pathoanatomical and biochemical features. The study supports the hypothesis that tumour cell clones with different ER content are selected and adapted to grow in various anatomical sites. Moreover, the ER status of the primary tumour seems to be more important for the prognosis than the ER status of bone and liver metastases.