Cisplatin plus 5-FU for the treatment of adenocarcinoma of the colon.

Cisplatin plus 5-FU appears to have significant additive activity in various tumors, such as head and neck carcinoma and esophageal cancer. A partial explanation for this may be drug synergism, which has been noted in the L1210 leukemia model. Based on these data, a prospective trial of weekly bolus 5-FU (15 mg/kg) and cisplatin (60 mg/m2) given every 3 weeks was initiated at Indiana University. Forty-one patients, of whom 38 are fully evaluable for response, were treated with these two drugs. Ten partial and one complete response (complete + partial response rate = 29%) were observed in the 38 evaluable patients. Thirteen additional patients had stable disease for greater than or equal to 3 months. The median durations of remission and survival time were 6 and 10.3 months, respectively. Myelosuppression was unusually severe, with granulocyte counts less than 1000/mm3 in 65% of patients, including four patients with granulocyte count nadirs less than 100/mm3. Three patients developed granulocytopenic fever, with two drug-related deaths (sepsis, hyperosmolar coma). Nearly all patients had nausea and vomiting, but this was not a treatment-limiting toxic effect in any patient. Although this combination suggests a higher response rate than usually seen with bolus iv 5-FU in colon cancer, a trial comparing 5-FU alone or with cisplatin to determine whether true synergy exists is currently underway.