Clinical Correlation of the Histoculture Drug Response Assay in Gastrointestinal Cancer.

The histoculture drug response assay (HDRA) with tumors histocultured on Gelfoam® was tested for clinical correlation for advanced gastric and colorectal cancer patients. In one study, 29 patients were treated with drugs shown to be ineffective in the HDRA, and all 29 cases showed clinical chemoresistance. In nine patients treated with drugs shown to be effective in the HDRA, six showed clinical chemoresponse and three showed arrest of disease progression. In a study of 32 patients with stage III and IV gastric cancer treated with mitomycin C and 5-fluorouracil (5-FU), the survival rate of 10 patients whose tumors were sensitive to either mitomycin C and/or 5-fluorouracil in the HDRA was significantly better than that of 22 patients whose tumors were insensitive to both drugs in the HDRA. Twenty-nine patients with stage III and IV colorectal cancer without remaining measurable tumor lesions after surgery were treated with fluoropyrimidines adjuvantly. The recurrence-free survival rate of 7 patients whose tumors were sensitive to 5-fluorouracil in the HDRA was significantly better than that of 22 patients whose tumors were insensitive in the HDRA. In a companion study of 128 gastric cancer patients whose tumors were evaluated in the HDRA, the overall and disease-free survival rates of the HDRA-sensitive group were found to be significantly higher than those of the HDRA-resistant group, treated with the same drugs.