Effects of preoperative chemotherapy on gastric adenocarcinomas. A morphologic study of 25 cases.

BACKGROUND. Surgical neoadjuvant therapy for gastric adenocarcinoma affords the opportunity to evaluate critically the histologic effects of preoperative chemotherapy. METHODS. Morphologic alterations in gastric adenocarcinomas were examined in the surgical-resection specimens from 25 patients after 6 weeks of preoperative chemotherapy. The group included 1 patient with a complete response; 4, with subtotal responses; 4, with partial responses; and 16, with no response to preoperative chemotherapy. RESULTS. Histologic manifestations of preoperative chemotherapy included mucosal edema, aggregates of histiocytes in the submucosa and muscularis externa, and stromal fibrosis of the submucosa and muscularis externa. Cytologic manifestations were uncommon and included a single case of signet ring cell carcinoma with diminution of the cytoplasmic vacuoles after preoperative chemotherapy. Clinical follow-up was limited, but 3 of the 25 patients died within 5-8 months after the diagnosis of gastric adenocarcinoma. The gastric-resection specimens from these three patients did not show any histologic manifestations of preoperative chemotherapy. CONCLUSION. As in tumors at other sites, the efficacy of surgical neoadjuvant therapy for gastric adenocarcinoma can be assessed, based on the histologic response of the resected tumor to preoperative chemotherapy.