Response to endocrine therapy and breast cancer differentiation

A case of pulmonary metastasis from breast cancer following an 18-year disease-free interval that responded to tamoxifen treatment

A 61-year-old woman was admitted to our hospital with an abnormal shadow on chest roentgenogram. She had undergone a radical mastectomy for right breast cancer 18 years previously. Since pleural dissemination was noted at the time of thoracotomy, only tumor biopsy was performed. Although a decisive diagnosis could not be obtained histologically, the tumor resembled breast cancer and the estrogen receptor status was positive. She underwent post-operative chemotherapy and tamoxifen treatment. After tamoxifen treatment, complete response was observed. The patient is now doing well without recurrence about 10 years after thoracotomy. Based on the clinical course, we obtained both a definitive diagnosis and complete remission.

The significance of hormone receptors to predict the endocrine responsiveness of human breast cancer

The paper reviews clinical data on the correlation between the response of human breast cancer to endocrine therapy and the tumour cell content of receptors of e.g. oestrogen (OeR), progesterone (PgR), androgens (AR) and the epidermal growth factor (EGFR). In advanced disease there is a well established correlation between OeR content and the rate of objective response to all types of endocrine therapy. However, if selection of first-line salvage therapy based on OeR status will result in prolonged survival or improved quality of life remains controversial. Assays of PgR, AR, and EGFR--in addition to OeR--increase the predictive ability but no study has been able to define an entirely unresponsive subgroup of patients on the basis of receptor status. In the adjuvant setting conflicting relationships have been reported. Some authors have found a benefit with tamoxifen also among OeR negative patients whereas others have concluded that adjuvant tamoxifen is ineffective in such patients. Prospective randomized trials are warranted to further assess the predictive value of hormone receptors, particularly in view of the increased frequency of thrombotic events and endometrial cancer associated with long-term adjuvant tamoxifen.

The expression of milk fat globule antigens within human mammary tumours: relationship to steroid hormone receptors and response to endocrine treatment

The value of steroid hormone receptors for the management of advanced carcinoma of the breast is often limited by the lack of availability of fresh tissue. Differentiation antigens may be estimated on paraffin-embedded fixed material by immunostaining, and the aim of this study was to determine whether staining with the monoclonal antibody raised to human milk fat globule (HMFG-1) could replace receptor measurements. The indirect immunoperoxidase technique was used to stain formalin-fixed paraffin-embedded tumour samples from 168 patients. All received tamoxifen or ovarian ablation as first-line systemic therapy, and all were evaluable for response (UICC criteria). One hundred and sixty-seven had oestrogen (ER) and progesterone receptors (PR) estimated. HMFG-1 staining was assessed as the percentage of tumour cells stained, and by the site of stain. The proportion of cells stained was highly correlated with both ER (P less than 0.0001) and PR (P less than 0.0001) and with response. When greater than or equal to 30% cells stained, 53 of 69 (77%) responded; when 20-29% stained 10 of 19 (53%) responded, when 10-19% stained seven of 19 (37%) responded, and when less than or equal to 9% cells stained 16 of 61 (26%) responded (P less than 0.0001). The median survival of patients with tumours that stained greater than or equal to 30% cells was 36 months, and with no cells stained, 11 months (P less than 0.0001). ROC (receiver operator characteristic) curves found that the optimum threshold for sensitivity and specificity of response prediction was greater than or equal to 20% cells stained. Cox's multiple regression analysis of 42 variables indicated that PR was the most important predictor of survival (P less than 0.000001), but that after PR the percentage of cells stained with HMFG-1 was the most important (P less than 0.0001). We conclude that immunostaining for HMFG-1 gives similar information to receptor status, and has the advantage that fixed archival tissue may be used.

Expression of differentiation antigens within human mammary tumours is related to response to endocrine therapy and survival

Human mammary tumours which are histologically well differentiated are more likely to synthesize receptors for estrogen (ER) and progesterone (PR) and to respond to systemic endocrine therapy. The aim of this study was to explore the relationship between differentiation, receptors and endocrine responsiveness in more detail by relating the expression of putative differentiation antigens within tumours to ER, PR and response to treatment. Sections of the primary tumours of 160 patients with advanced evaluable breast cancer were immunostained with 2 monoclonal antibodies (MAbs) (HMFG1 and HMFG2) raised against putative differentiation antigens found on the membranes which surround the milk fat globule. Tumours were highly heterogeneous with respect to antigen expression. However, the number of cells which expressed the antigens was highly correlated with ER and PR concentrations and with response to endocrine therapy. In tumours where greater than or equal to 20% of cells expressed the antigen recognized by HMFG1, 73% responded to endocrine therapy; this was similar to the response predicted by ER (67%) and PR (73%). Expression of HMFG1 was correlated with survival from the start of endocrine therapy (p less than 0.0001) to the same degree as ER and PR. Patients with tumours which expressed ER, PR and HMFG1 had the highest response rate (87%) and survival (median 49 months); the response in tumours which expressed none of these phenotypes was 13% and the median survival of these patients was 9 months. These results suggest that cells which express differentiation antigens also express ER and PR. Differentiated cells within mammary tumours may therefore be the target cells for systemic hormone, and also the source of factors which control tumour growth.

Histological grade, elastosis, DNA ploidy and the response to chemotherapy of breast cancer

The relationships between response to chemotherapy of advanced breast cancer and the histological type, grade, elastosis content and DNA ploidy of the primary tumours were examined using paraffin-embedded tissue derived from 125 patients. Higher response rates were seen amongst tumours with a high elastosis content and those that were diploid. However, selection of patients with advanced breast cancer for chemotherapy will not be assisted significantly by an assessment of these features in the primary tumour.

Oestrogen receptors in primary and advanced breast cancer: an eight year review of 704 cases

ER content of primary tumour tissue has been examined in 704 patients presenting with operable breast cancer. The median follow-up is now 84 months and no patient has received adjuvant therapy of any kind. ER status is related to histological grade, menopausal status, initial site of metastases and subsequent response to endocrine therapy. A significant advantage in terms of survival is found in ER positive patients which is confined to those lymph node positive at mastectomy. DFI is also significantly related to ER status in lymph node positive patients. Survival after the symptomatic presentation of metastases and the institution of endocrine therapy is prolonged in patients with ER positive tumours. The overall response rate to endocrine therapy in assessable patients with ER positive tumours is 32%. By combining the ER status and histological grade of tumour tissue, a group of patients comprising 28% of those assessable to endocrine therapy can be identified (ER positive, grade I and II) with a response rate of 46%.