Abstract. Using trace three-dimensional culture, the collagen gel droplet-embedded culture drug sensitivity test (CD-DST) can be tested even in cases with a small number of cells, including oral squamous cell carcinoma (OSCC), and evaluation of the antitumor effect with a drug concentration close to the in vivo level is possible. The present report aimed to evaluate the utility of the CD-DST in the assessment of the in vitro efficacy of single-agent and multidrug combination chemotherapy for OSCC in comparison with the clinical response rates and to examine the possible clinical application of CD-DST for such cases. A total of 33 OSCC patients from whom 33 samples were obtained from January 2010 to September 2015 were included. CD-DST was performed, individually and in combination, on the three drugs [i.e., cisplatin (CDDP), 5-fluorouracil (5-FU), and docetaxel (DOC)] and on super selective intra-arterial infusion chemoradiotherapy (IACRT). The overall evaluable rate of the CD-DST in OSCC was 81.8% (27 of 33 cases) and the sensitivity to each anticancer drug was evaluated. The in vitro efficacy rates of IACRT, cisplatin + 5-fluorouracil, and docetaxel + cisplatin + 5-fluorouracil (TPF) confirmed the estimated clinical response rates. In 14 of 33 patients, the results of CD-DST were compared with clinical efficacy, which was judged based on measurable lesions on imaging. For TPF therapy, the sensitivity test of the IACRT had a positive predictive value of 90.9% (10 of 11 cases) and a negative predictive value of 100% (3 of 3 cases); the accuracy of the susceptibility test for the anticancer agents was 92.8% (13 of 14 cases). The CD-DST may be useful in selecting multidrug combination chemotherapy and IACRT for OSCC, however, accumulation of further clinical data is required in the future.
IntroductionThe treatment of advanced or unresectable oral squamous cell carcinoma (OSCC) is multidisciplinary and entails the use of both multidrug combination chemotherapy and radiotherapy (1-3). The usefulness of super selective intraarterial infusion chemoradiotherapy (IACRT) to deliver high concentrations of anticancer drugs to tumors has been reported (4). The selection of such anticancer drugs for IACRT had been based on statistical information and clinical reports on a number of cases (1-3); however, the expected therapeutic effects of these anticancer drugs have not been consistent and adverse events were common. Therefore, drug sensitivity testing prior to administration of an anticancer agent is ideal to avoid the serious side effects of less effective anticancer drugs. Collagen gel droplet-embedded culture drug sensitivity test (CD-DST) uses an image colorimetric method to assess the combination of an anticancer drug and microcollagen gel embedded in a three-dimensional serum-free culture medium (3 to 10x10 3 cells/30 µg/drop) (5,6). It is a susceptibility test that is currently widely applied in various clinical fields, including gastrointestinal cancer (7-9). However, reports on the use of CD-DST in OSCC were few a...