Succinate dehydrogenase inhibition test for evaluating head and neck tumors.

In vitro chemosensitivity was evaluated in human head and neck cancers using the succinate dehydrogenase (SD) test and the results were compared to findings in cases of malignant lymphomas and gastric cancers. Tumor fragments were exposed to several antitumor drugs at ten times the peak plasma concentration and assayed for SD activity. Decrease of SD activity was most prominent in the malignant lymphomas in cases of exposure to ADM, ACR, DDP, MMC and CQ; in which the average of SD activity decreased to below 30%. In the squamous cell carcinomas, SD activity below 40% was also observed with the same drugs, while the SD activity of gastric cancers was about 50%. There was a change of chemosensitivity following chemotherapy. The use of the SDI test will aid in selecting drugs for the prevention of recurrence or metastasis in head and neck cancers.