The Role of Chemotherapy Sensitivity and Resistance Assays in Ovarian Cancer

Kim, Jong Hyeok

Abstract

Chemotherapy sensitivity and resistance assays (CSRAs) test whether a sample of a patient's tumor tissue shows a response such as reduced tumor survival when exposed to selected chemotherapy drugs under laboratory conditions. A variety of in vitro techniques of CRSAs have been developed so far; human tumor cloning assay (HTCA), the differential staining cytotoxicity (DiSC) assay, the methylthiazolyl-diphenyl-tetrazolium bromide (MTT) assay, the adenosine triphosphate (ATP) assay, the extreme drug resistance (EDR) assay and histoculture drug response assay (HDRA). CSRAs offer the potential of tailoring treatment to individual patients using effective agents while sparing unnecessary ones. Theoretically, use of CRSAs could lead to more rational decisions. CSRAs have been evaluated in several studies for predicting chemosensitivity to ovarian cancer and about 90% of predictive accuracy was reported. However, none of these methods have yet been applied clinically because many complex factors determine the outcomes of chemotherapy and may impair the ability of assay results to predict in vivo tumor response and other outcomes. For example, the tissue sample tested might not be representative of the behavior of the patient's tumor. In addition, there is an imperfect relationship between tumor response and survival, or occurrence of treatment-associated adverse events, which are most important to patients. Therefore large scale, randomized trials are needed to evaluate whether the result of CSRAs is correlated with the patient's outcome, including response to the chemotherapy and survival. If successful, this one small step will be able to be a giant leap to individualized treatment in patients with ovarian cancer in the future.