Benchmarking of gastric cancer sensitivity to anti-cancer drugs ex vivo as a basis for drug selection in systemic and intraperitoneal therapy

BACKGROUND: The choice of drugs for treatment of advanced gastric cancer (GC) is empirical. The purpose of the current study was to benchmark ex vivo the sensitivity of GC tumor cells from patients to standard cytotoxic and some newly introduced targeted drugs (TDs), as a basis for drug selection in the treatment of GC. METHODS: Tumor cell samples from patients with GC were analyzed for sensitivity to 5-fluorouracil, cisplatin, oxaliplatin, irinotecan, mitomycin C, doxorubicin and docetaxel as well as for the targeted drugs bortezomib, sorafenib, sunitinib and rapamycin using a short-term in vitro assay based on retention of viable tumor cells of fluorescent fluorescein. Samples of normal mononuclear cells, chronic lymphocytic leukemia, ovarian cancer and colorectal cancer were included for comparison. RESULTS: The GC samples were essentially as sensitive to the standard drugs and the TDs as those from colorectal cancer whereas the ovarian cancer samples were more sensitive. The individual GC samples varied considerably in sensitivity to increasing concentrations of the clinically used standard drugs. In GC, cisplatin was cross-resistant to oxaliplatin and 5-fluorouracil which, on the other hand, was not cross-resistant to the other cytotoxic drugs. The activity of sunitinib did not obviously correlate to that of the standard drugs. CONCLUSION: Ex vivo assessment of drug sensitivity of tumor cells from patients with GC is feasible and may provide information that could be useful for selection of drugs for treatment. Drug sensitivity varies considerably between and within individual samples arguing for individualized selection of drugs for chemotherapy.