Is there a role for pretherapeutic chemosensitivity testing in breast cance?

The title of this paper poses a question to which the short answer must be "yes" What oncologist would not wish to be in the enviable position of an i nfectious diseases physician, who can treat a patient with a serious infect ion knowing that the organism is sensitive to the antibiotic prescribed? Un fortunately, cancer cells are not as easy to grow as most bacteria and prev ious attempts to produce a feasible chemosensitivity assay for clinical use have been largely unsuccessful. Yet the rationale for such assays is sound : not all tumors of one histological type respond in the same way to the sa me agent. We know that this heterogeneity reflects the molecular phenotype. Over the last 8 years, a new tumor chemosensitivity assay (ATP-TCA) based on highly sensitive luminescence technology has been developed to the point where it is now entering phase III trials in ovarian cancer. Results in br east cancer are similarly encouraging, although as yet few patients have be en treated prospectively according to the results of the assay. The assay h as 97 % evaluability for surgical biopsies with 76 % concordance between cl inical response and chemosensitivity. Results from neoadjuvant studies in w hich needle biopsies and tumor from the mastectomy specimen obtained after three cycles in six cases were tested show the rapid development of resista nce in four cases to combination chemotherapy. However, nine courses of che motherapy given on the basis of the ATP-TCA resulted in partial or complete responses in all nine patients. Phase III clinical trials of ATP-TCA direc ted therapy against empirical therapy are in progress.