Response of the primary lesion in gastric cancer to chemotherapeutic trials

Background: We wish to clarify some points in the evaluation of primary tumors in gastric cancer trials, particularly the response rate and patient survival. Methods: This study includes 226 patients with advanced gastric cancer who had no prior treatment except surgery, and who had been enrolled into 1 of 4 Japan Clinical Oncology Group trials. The regimens for these 226 patients were tegafur and mitomycin C in 50, a combination of tegafur and uracil and mitomycin C in 39, 5'-deoxy-5-fluorouridine and cisplatin in 49, etoposide, doxorubicin, and cisplatin in 42, and 5-fluorouracil and cisplatin in 46 patients. Antitumor responses were evaluated by the Japanese evaluation criteria. Results: Of the 226 patients, 192 (85%) had primary cancers. Only 57 of 192 had roentgenographically measurable tumors. The response rate of the primary cancers was significantly lower than that of measurable metastatic lesions (P < 0.01). Forty-five overall responders who had both primary and metastatic tumors were divided into 31 responders and 14 nonresponders, with reference to primary cancers. The 31 patients who had a response in the primary cancer lived significantly longer (P< 0.05) than the 14 nonresponders, even though there was no significant difference in patient backgrounds between the 2 groups. This difference in survival became even more remarkable after 1 year. Conclusions: Although some questions remain unresolved, evaluation of primary cancer can be meaningful, and the response of primary cancers may be an indicator for long-term survival.