656P - Treatment strategy for conversion therapy using docetaxel/CDDP/S-1 (DCS) or DCS-trastuzumab (DCS-T) according to HER2 status in metastatic gastric...

Date 29 September 2014
Event ESMO 2014
Session Poster Display session
Topics Anti-Cancer Agents & Biologic Therapy
Gastric Cancer
Personalised Medicine
Presenter Yasushi Sato
Citation Annals of Oncology (2014) 25 (suppl_4): iv210-iv253. 10.1093/annonc/mdu334
Authors Y. Sato1, H. Ohnuma2, T. Takayama3, T. Sagawa4, M. Hirakawa2, Y. Sato4, Y. Takahashi4, M. Takahashi5, M. Maeda6, S. Katsuki7, M. Hirayama8, K. Takada1, T. Hayashi1, T. Sato1, K. Miyanishi1, M. Kobune1, R. Takimoto1, T. Nobuoka9, K. Hirata9, J. Kato1
  • 1Depertment Of Medical Oncology And Hematology, Sapporo Medical University, 0608543 - Sapporo/JP
  • 2Depertment Of Medical Oncology And Hematology, Sapporo Medical University School of Medicine, 0608543 - Sapporo/JP
  • 3Department Of Gastroenterology And Oncology, University of Tokushima Graduate School, 7708503 - Tokushima/JP
  • 4Department Of Gastroenterology, Hokkaido Cancer Center, Sapporo/JP
  • 5Division Of Gastroenterology, Sapporo Sapporo Kyoritsu Gorinbashi Hospital, Sapporo/JP
  • 6Division Of Gastroenterology, Steel Memorial Muroran Hospital, Muroran/JP
  • 7Division Of Gastroenterology, Otaru Ekisaikai Hospital, Otaru/JP
  • 8Division Of Gastroenterology, Tonan Hospital, Sapporo/JP
  • 9Department Of Surgery, Surgical Oncology And Science, Sapporo Medical University School of Medicine, Sapporo/JP

Abstract

Aim

The feasibility of "conversion chemotherapy,” which is an attempt to convert an initially unresectable cancer to resectable status, has not been fully examined in patients (pts) with unresectable metastatic gastric cancer (UMGC). We have developed a triplet-drug combination regimen consisting of docetaxel, CDDP, and S-1 (DCS), and recently we carried out a feasibility study of DCS-trastuzumab (DCS-T) for pts with HER2-positive UMGC. We reported that both regimens are associated with a high response rate and downstaging in pts with initially UMGC. The aim of this study was to clarify the conversion rate and prognosis in pts with initially UMGC treated with DCS or DCS-T according to their HER2 status.

Methods

Pts with UMGC were enrolled in clinical trials of DCS or DCS-T chemotherapy. Pts received oral S-1 (40 mg/m2 BID) on days 1-14, intravenous cisplatin (60 mg/m2), and docetaxel (50-80 mg/m2) on day 8 every 3 weeks. In the DCS-T group, trastuzumab was added on day 8 at a dose of 8 mg/kg in the first cycle and 6 mg/kg in the second cycle and thereafter. Conversion surgery was considered when pts underwent downstaging as determined by conventional examinations or staging laparoscopy and were deemed able to tolerate a curative surgical operation.

Results

The study included 100 pts in the DCS group: median age, 63 years; PS, 0/1/2: 47/27/26 pts; and well-differentiated/undifferentiated adenocarcinoma, 39/61 pts. The objective response rate was 81.4%. Conversion was achieved in 35/100 (35%) pts and 28/33 (84.8%) underwent curative surgery. A total of 24 (72.7%) of the 33 resected cases were histological chemotherapeutic responders. The median OS of the resected pts was 47.8 months. The DCS-T study included 16 pts: median age, 60 years; PS 0/1/2, 10/4/2 pts; HER2 3 + , 13 pts; HER2 2 + /FISH + , 3 pts. The objective response rate was 100%. Non-curative factors disappeared in 10 of 16 cases and R0 resection was carried out in 9 (56.3%). A pathological response was seen in 8 (88.9%) of the resected cases. At a median follow-up of 14.1 months (range, 4.7 – 29.3 months), median OS was not yet reached.

Conclusions

DCS and DCS-T provided a high conversion rate and better prognosis. Our data warrant further prospective investigations to establish a conversion therapeutic strategy for UMGC pts according to their HER2 expression status.

Disclosure

All authors have declared no conflicts of interest.