Prediction of anti-tumour effect of thermochemotherapy with in vitro thermochemosensitivity testing for non-small cell lung cancer
We investigated whether it is possible to predict the antitumour effects of thermochemotherapy from the results of anticancer agent sensitivity testing. We produced a nude mouse cancer model using 4 lung cancer cell lines. Animals were divided into 4 groups: Thermotherapy (HT group), chemotherapy (CT group), thermochemotherapy (HT+CT group), and no therapy (NT group). Comparison of in vivo and in vitro effects were performed using cisplatin (CDDP), doxorubicin (ADR) and vinorelbine (NVB). In vivo thermotherapy was performed using the Thermotron RF IV, and radiofrequency (RF) capacitative hyperthermia device that induces a localised temperature of 42.0 degrees C for 45 min. The collagen gel embedded culture drug sensitivity test (CD-DST) was used for in vitro chemosensitivity analysis of the anticancer agents. In vitro thermochemotherapy was performed using a modified CD-DST method, with the incubator set at 42.0 degrees for the first hour of the 24 hours drug exposure period. A good correlation was seen between in vivo and in vitro treated/control ratios (T/C%) in the HT group (R = 0.91, p = 0.09). Good correlations were also seen between in vivo and in vitro T/C in all cell lines in the CT group (R = 0.759, p = 0.09) and the HT+CT group (R = 0.65, p = 0.02). True positive rate was 87.5% (7/8), and true negative rate was 100% (4/4). Sensitivity, specificity and accuracy were 100% (7/7), 80% (4/5), and 91.7% (11/12) respectively. A modified CD-DST using an exposure temperature of 42 degrees C can be used to predict the antitumour effect of thermochemotherapy.