Prognostic impact of response to second-line chemotherapy on overall survival of patients with advanced gastric cancer

Abstract

e15551 Background: It has been debated on whether tumor response to first-line chemotherapy (CT) would be reliable predictor for overall survival (OS) of cancer patients (pts). In case of advanced gastric cancer (AGC), many pts receive 2nd line CT after failure to 1st line treatment, so response to 2nd line CT as well as 1st line could affect OS. Methods: We retrieved clinical data of a total of 1,335 pts with AGC treated with palliative CT from January 2000 to December 2006 in National Cancer Center, Korea, including 757 pts who also received 2nd line CT. Responses to 1st and 2nd line CT were evaluable in 504 pts. Retrospective analysis was done to find correlation between objective tumor response to 1st and 2nd line CT and OS of the 504 pts, whom we divided into 4 groups: responders to both 1st and 2nd line CT (RR group); responders to 1st but not to 2nd line CT (RN group); responders to 2nd but not to 1st line CT (NR group); and nonresponders to both 1st and 2nd line CT (NN group). Results: Objective response rate of 1st and 2nd line CT was 41.7% and 12.3%, respectively. Responders to 1st line CT had a trend to respond to 2nd line CT (ORR of 2nd line CT in responders vs nonresponders to 1st line CT: 15.7% vs 9.9%, p = 0.049). 33/177/29/265 pts were assigned to each of RR/RN/NR/NN group, respectively. With median follow-up of 48.7 mo (range 23.2 - 93.7), median OS was 12.7 mo (95% CI 11.8–13.6). Baseline characteristics were balanced between 4 groups except higher hemoglobin and serum albumin level in RR group, younger median age in NN group, and fewer pts with poor performance status or poorly differentiated histology in NR group. Overall survival of RR, RN, NR, and NN group was 31.8 mo, 15.5 mo, 18.9 mo, and 9.2 mo, respectively (p<0.001). Multivariate analysis revealed relapsed disease after curative surgery, well-differentiated histology, absence of pulmonary metastasis, higher serum albumin level, lower serum bilirubin and alkaline phosphatase level, response to both of 1st line and 2nd line CT were reliable factors for favorable survival. Conclusions: Among the patients who received 2nd line chemotherapy for AGC, response to 2nd line CT was strongly associated with OS regardless of previous response to 1st line CT. No significant financial relationships to disclose.