Retrospective study of the patients with unresectable gastric cancer (UNGC) who underwent a gastrectomy after receiving S-1 or S-1 combination chemotherapy (S-1+α)

Abstract

e15668 Background: At the 2007 ASCO annual meeting, JCOG 9912 and the SPIRITS trial showed that S-1 (S) and CDDP/S-1 (S+P) therapy to now be an accepted standard chemotherapy for advanced and recurrent gastric cancer (ARGC). Today in Japan, S- 1+αincluding S+DTX, S+CPT-11 and S+PTX are the mainstay treatments for ARGC. There are some case reports of pts with UNGC who were operated on due to the good anti-tumor effect of S-1+α, however, no consensus for performing a gastrectomy after chemotherapy has yet been reached. This study aims to identify the factors which make it appropriate to perform a gastrectomy after S- 1+α and to examine the validity of this chemotherapeutic regimen in combination with surgery. Methods: Twenty-five chemo-naïve pts with UNGC who received S-1+α (excluding neo-adjuvant) between May 2005 and Dec. 2007 were retrospectively reviewed, using the RESIST, Kaplan-Meier method, and Japanese Classification of Gastric Carcinoma (Eng. ed.). Results: The characteristics were: mean age 62; sex: M/F=18/7; cancer status; locally advanced (L):11, distant metastasis (D):9, lymph node swelling ≥group 3 (N):12, and peritoneal dissemination (P):11. Treatment regimens; S:13, S+DTX:3, and S+P:9. The median number of courses was 5. RR was 56% (PR:14, SD:9, PD:2). MST was 780 days. Twelve pts underwent a gastrectomy. The reasons for performing an operation were downstaging (DOWN):8, and palliative (PAL):4 (anemia:2/passage disturbance:2). The features were DOWN (M/F=5/3/65 yrs/PR:8/L:6, D:0, N:4, P:3) and PAL (M/F=4/0/57 yrs/SD:4/L:1, D:3, N:1 P:1). The median PFS and mean OS were 445 days and 312 days, respectively. No significant difference was observed between DOWN and PAL regarding the PFS and OS. All PAL cases were free from painful symptoms. Three pts received a curative A resection. In addition, 8 pts experienced histological changes, in particular, one pt achieved Grade 3 (No viable tumor cells were found.). Ten pts received adjuvant chemotherapy. Nine pts are alive at this writing. Conclusions: The findings of this study suggest that the above described chemotherapeutic regimen combined with a second-look gastrectomy might therefore be a new potentially effective strategy for the treatment of UNGC. No significant financial relationships to disclose.