Selection of adjuvant chemotherapy for gastric cancer using objective criteria

Precise prediction of recurrence risks is of importance in the selection of adjuvant chemotherapy. A proportional hazards regression analysis was performed to seek objective criteria for 234 gastric cancer patients. The analysis showed that a high level of carcinoembryonic antigen (CEA) in peritoneal washing (100 ng/g protein) was an independent risk factor for peritoneal recurrence, and a high MMP9 (92 KD type IV collagenase) level in serum was a powerful indicator of hematogenous recurrence. In addition, the PHREG analysis in 1453 gastric cancer patients showed that MF therapy (mitomycin C i.v. + fluoropyrimidine derivatives) and PF therapy (Cisplatin i.p. + fluoropyrimidine derivatives) might be effective in the prevention of hematogenous and peritoneal recurrence after a curative operation, respectively. Based on these findings, a recurrence type-oriented adjuvant chemotherapy, i.e., PF therapy for high CEA group and MF therapy for high MMP9 group, was designed. The retrospective analysis showed significant survival benefit in stage III gastric cancer patients who underwent a curative operation. The 5-year survival rate was 67%, while that of the historical control was 46%. Prediction of recurrence type using CEA levels in peritoneal washings and MMP9 levels in sera may be of value in the selection of a proper population of patients for PE or MF therapy after gastrectomy. The selection system of adjuvant chemotherapy using such objective criteria may improve the prognosis of gastric cancer patients and keep their good quality of life through the selection of proper candidates and by eliminating patients in no need of therapy.