The association of objective response and overall survival in patients with inoperable or metastatic gastric and esophagogastric junction (EGJ) cancer: A pooled analysis of individual patient data from first-line clinical trials.

Abstract

4095 Background: The aim of the study is to determine whether the achievement of an objective response to first-line chemotherapy is prognostic of patient’s outcome in gastric/EGJ adenocarcinoma. Methods: Individual patient (pts) data from prospective first-line trials conducted by a single study group were used. Patients received platin/5-FU based chemotherapy with or without docetaxel. Responses were evaluated according to WHO criteria in all trials. Response data, patients’ characteristics (age, sex, entity, histological type, primary location, ECOG PS, and type and number of metastatic sites), type of chemotherapy, and overall survival data were analyzed. Results: 612 pts were included. Median age was 66 yrs; 31.5% had ECOG status 0, 58.3% ECOG 1, and 9.8% ECOG 2 & 3. Gastric primaries were found in 44.4% and EGJ in 35.8% of pts (19.7% were overlapping/not evaluable). According to Lauren classification, 36.8% had intestinal, 32.4% diffuse, and 8.5% mixed types (22.4% were not classifiable). 64.5% had positive non-regional lymph nodes (LN) involvement, 14.1% LN involvement without other metastases, 33.3% had peritoneal carcinomatosis, 44.0% liver and 16.7% lung metastases. Response rates were complete (CR) in 3.1%, partial (PR) in 36.4%, stable disease (SD) in 34.5%, and progressive disease (PD) in 15.0% pts (10.9% were not evaluable). Overall response rate (OR; CR + PR) was 39.5%. Median overall survival times in pts with CR vs PR vs SD vs PD were 37.9 vs 14.7 vs 10.9 vs 5.2 months, respectively; p=1.26 x 10-33). OR (CR or PR) also strongly predicted OS (16.7 vs 8.1 months in pts with vs no OR, p=1.08 x 10-17). OR remained the strongest predictor of OS in the multivariate analysis (p=6.55 x 10-7) including all baseline criteria mentioned above followed by ECOG PS (p=0.048) and the presence of non-regional LN as the only site of metastasis (p=0.034). Conclusions: The achievement of an objective response is the strongest predictor of survival in pts with gastric and EGJ cancer and could serve as a surrogate marker if validated.