Correlation of the clinical response to chemotherapy in breast cancer with ex vivo chemosensitivity.

Chemotherapy for breast cancer is given on the basis of empirical information from clinical trials, an approach which falls to take into account the known heterogeneity of chemosensitivity between patients. Previous attempts to determine chemosensitivity ex vivo have been disappointing, but in this study results from a newly developed tumor chemosensitivity assay (TCA) have been correlated prospectively with patient response. In this study, we have used heterogeneity data for standard regimens obtained from 116 breast TCAs to set sensitivity/resistance thresholds which were then used to interpret the results from those with known clinical responses. Assay evaluability was 97% in surgical biopsies. Clinical follow-up of stage III/ IV assessable disease was obtained from 27 breast tumors which were successfully tested for chemosensitivity, including 13 needle biopsies. The ATP-TCA assay predicted response correctly in 22 out of 29 (76%) tumors with clinically evaluable disease, suggesting that it is capable of predicting outcome in individual patients. Assays were performed in seven patients before and after chemotherapy using residual or recurrent tumor tissue. Four cases with initial sensitivity showed a decrease in sensitivity within 6 months of starting chemotherapy, while two others without clinical resistance were still sensitive by TCA. All nine courses of therapy given on the basis of TCA sensitivity resulted in partial or complete responses. Controlled trials of TCA-directed treatment against standardized empirical therapy should be conducted before this technology is widely adopted to assess its impact on rates of response, survival and the cost of treatment.

Effects of treatment on the histopathology of leprosy.

AIMS: To identify the histological changes in leprosy skin lesions over the first few weeks after the start of leprosy treatment and to examine their relationship to reversal reaction. METHODS: Sequential skin biopsy during treatment with multiple drug therapy. In this study, a series of 28 patients was studied, from whom two or more biopsies were taken at two week intervals. Fourteen patients had paucibacillary leprosy (PBL) and 14 had multibacillary leprosy (MBL). RESULTS: In most cases, granuloma fraction and bacterial index fell during treatment, the bacterial index being less sensitive than the granuloma fraction. Since the biopsies were fixed in buffered formalin and processed through to paraffin wax, little immunohistochemistry was feasible. However, there was strong evidence of immune activation, with increased expression of HLA-DR in the granulomas of MBL and PBL cases: the epidermis also expressed HLA-DR in several patients. Such changes may reflect gamma IFN production from granuloma lymphocytes. Patients with reversal reaction often showed HLA-DR expression on admission which decreased with corticosteroid treatment. CONCLUSIONS: The results suggest that activation of cell mediated immunity in leprosy lesions occurs during treatment with multiple drug therapy and may not be restricted to those with clinical evidence of reversal reaction.

The influence of storage on cytotoxic drug activity in an ATP-based chemosensitivity assay.

The use of viability assays to assess the effect of antineoplastic agents on cell lines and tumor cells is an important investigative tool and may have clinical relevance. Such assays require very small quantities of drugs and it is the practice of many laboratories to freeze aliquots of drugs for use in these assays as required. We have investigated the stability of 11 different agents in an ATP-based chemosensitivity assay which is being evaluated for clinical use. The results show that most drugs maintain their biological activity well when frozen at -20 degrees C for periods up to 24 months, or occasionally at room temperature. However, 4-hydroperoxycyclophosphamide and mitomycin C are exceptions to this rule, and should not be kept frozen for more than 2-3 months. Cisplatin is unstable when frozen and then thawed, but maintained activity at room temperature for at least 6 months. Since biological activity may not correlate completely with chemical stability, further studies on the effect of storage are required, but it seems unlikely that the appropriate use of frozen aliquots is a major source of error in tumor chemosensitivity assays.