Katja Ott

Abstract BACKGROUND Neoadjuvant chemotherapy has shown some success in the treatment of gastric carcinoma, but objective parameters for measuring its effects are lacking. The authors performed the current study to determine which histomorphologic features are correlated with patient prognosis after chemotherapy. METHODS Thirty‐six patients with gastric carcinoma were treated with a combination of etoposide, doxorubicin, and cisplatin. The entire tumor beds of the specimens were evaluated histologically and compared with specimens treated with surgery alone. Thirty‐four patients were available for survival analysis (follow‐up period, 60–130 months). RESULTS None of the 36 patients had complete tumor regression, 4 patients had marked regression (less than 10% viable tumor), 9 patients had regression to 10–50% remaining viable tumor, and 23 patients had more than 50% viable tumor remaining. Currently, 9 patients are still alive (5‐year survival rate, 27%). Tumor regression was found to be correlated significantly with survival ( P = 0.01), but tumor size ( P = 0.002) and lymphatic vessel invasion ( P = 0.003) were better predictors of prognosis. CONCLUSIONS Histologic tumor regression grade is an objective measure of the effects of neoadjuvant chemotherapy in patients with gastric carcinoma, but its accuracy may be improved by adding additional staging variables such as tumor size and lymphatic vessel involvement. Cancer 2003;98:1521–30. © 2003 American Cancer Society. DOI 10.1002/cncr.11660

PURPOSE: Patients with locally advanced gastric cancer benefit from combined pre- and postoperative chemotherapy, although fewer than 50% could receive postoperative chemotherapy. We examined the value of purely preoperative chemotherapy in a phase III trial with strict preoperative staging and surgical resection guidelines. PATIENTS AND METHODS: Patients with locally advanced adenocarcinoma of the stomach or esophagogastric junction (AEG II and III) were randomly assigned to preoperative chemotherapy followed by surgery or to surgery alone. To detect with 80% power an improvement in median survival from 17 months with surgery alone to 24 months with neoadjuvant, 282 events were required. RESULTS: This trial was stopped for poor accrual after 144 patients were randomly assigned (72:72); 52.8% patients had tumors located in the proximal third of the stomach, including AEG type II and III. The International Union Against Cancer R0 resection rate was 81.9% after neoadjuvant chemotherapy as compared with 66.7% with surgery alone (P = .036). The surgery-only group had more lymph node metastases than the neoadjuvant group (76.5% v 61.4%; P = .018). Postoperative complications were more frequent in the neoadjuvant arm (27.1% v 16.2%; P = .09). After a median follow-up of 4.4 years and 67 deaths, a survival benefit could not be shown (hazard ratio, 0.84; 95% CI, 0.52 to 1.35; P = .466). CONCLUSION: This trial showed a significantly increased R0 resection rate but failed to demonstrate a survival benefit. Possible explanations are low statistical power, a high rate of proximal gastric cancer including AEG and/or a better outcome than expected after radical surgery alone due to the high quality of surgery with resections of regional lymph nodes outside the perigastic area (celiac trunc, hepatic ligament, lymph node at a. lienalis; D2).

PURPOSE: Preoperative chemotherapy in patients with gastroesophageal cancer is hampered by the lack of reliable predictors of tumor response. This study evaluates whether positron emission tomography (PET) using fluorine-18 fluorodeoxyglucose (FDG) may predict response early in the course of therapy. PATIENTS AND METHODS: Forty consecutive patients with locally advanced adenocarcinomas of the esophagogastric junction were studied by FDG-PET at baseline and 14 days after initiation of cisplatin-based polychemotherapy. Clinical response (reduction of tumor length and wall thickness by > 50%) was evaluated after 3 months of therapy using endoscopy and standard imaging techniques. Patients with potentially resectable tumors underwent surgery, and tumor regression was assessed histopathologically. RESULTS: The reduction of tumor FDG uptake (mean +/- 1 SD) after 14 days of therapy was significantly different between responding (-54% +/- 17%) and nonresponding tumors (-15% +/- 21%). Optimal differentiation was achieved by a cutoff value of 35% reduction of initial FDG uptake. Applying this cutoff value as a criterion for a metabolic response predicted clinical response with a sensitivity and specificity of 93% (14 of 15 patients) and 95% (21 of 22), respectively. Histopathologically complete or subtotal tumor regression was achieved in 53% (eight of 15) of the patients with a metabolic response but only in 5% (one of 22) of the patients without a metabolic response. Patients without a metabolic response were also characterized by significantly shorter time to progression/recurrence (P =.01) and shorter overall survival (P =.04). CONCLUSION: PET imaging may differentiate responding and nonresponding tumors early in the course of therapy. By avoiding ineffective and potentially harmful treatment, this may markedly facilitate the use of preoperative therapy, especially in patients with potentially resectable tumors.

PURPOSE: A previous study suggested that measurement of therapy-induced changes in tumor glucose metabolism by positron emission tomography (PET) with the glucose analog [18F]fluorodeoxyglucose (FDG) allows to select patients most likely to benefit from preoperative chemotherapy in adenocarcinomas of the esophagogastric junction (AEG). The aim of this study was to prospectively validate these findings by using an a priori definition of metabolic response. PATIENTS AND METHODS: Sixty-five patients with locally advanced AEGs were included. Tumor glucose utilization was quantitatively assessed by FDG-PET before chemotherapy and 14 days after initiation of therapy. Patients were classified as metabolic responders when the metabolic activity of the primary tumor had decreased by more than 35% at the time of the second PET. RESULTS: Metabolic responders showed a high histopathologic response rate (44%) with a 3-year survival rate of 70%. In contrast, prognosis was poor for metabolic nonresponders with a histopathologic response rate of 5% (P = .001) and a 3-year survival rate of 35% (P = .01). A multivariate analysis (covariates: ypT-, ypN-category, histopathologic response) demonstrated that metabolic response was the only factor predicting recurrence (P = .018) in the subgroup of completely resected (R0) patients. CONCLUSION: This study prospectively demonstrates that changes in tumor metabolic activity during chemotherapy predict response, prognosis, and recurrence. These data provide the basis for clinical trials in which preoperative treatment is changed for patients without a metabolic response early in the course of therapy. PET-guided induction therapy may even be applicable to earlier tumor stages because surgery is only minimally delayed in nonresponding patients.