Cisplatin/S-1 Offers Important Benefits Over Treatment Standard In Advanced Gastric Cancer

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Main Category: Cancer / Oncology
Also Included In: Ear, Nose and Throat;  Colorectal Cancer;  GastroIntestinal / Gastroenterology
Article Date: 22 Jun 2009 - 11:00 PDT

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ORLANDO - Cisplatin/S-1 (CS) is non-inferior to cisplatin/5-fluorouracil (CF) for the treatment of advanced gastric/gastro-esophageal carcinoma and at the same time offers important safety improvements, according to phase III results released recently at a meeting of the American Society for Clinical Oncology (ASCO).

S-1 is an investigational oral fluorouracil (FU) anticancer agent that combines tegafur, which is a pro-drug of 5-FU; gimeracil, which prevents 5-FU degradation by the body; and oteracil, which decreases 5-FU-related diarrhea. S-1 is given orally, while 5-FU and cisplatin are both administered by infusion.

Notably, the new data also showed superior overall survival in patients with diffuse-type histology, a group with a historically low survival rate.

"CS is an optimal substitute for CF in the treatment of advanced gastric cancer," Jaffer A. Ajani, M.D., professor of medicine at the M.D. Anderson Cancer Center in Houston Texas, said.

Dr. Ajani was the principal investigator of the study, which is known as the First-Line Advanced Gastric Cancer Study (FLAGS).

His group randomized patients to either S-1 (25 mg/m2 bid, d 1-21)/cisplatin (75 mg/m2 d1) q 28 d or 5-FU (1,000 mg/m2/d 5-d infusion)/cisplatin (100 mg/m2 d 1 ) q 28 d.

The primary endpoint was overall survival.

Results in 1,029 treated patients showed that the median overall survival was 8.6 months in patients randomized to CS and 7.9 months in patients assigned to CF, HR=0.92, p=0.1983.

As in earlier analyses of the FLAGS trial, CS-treated patients had significantly fewer grade 3-4 hematologic and grade 3 or greater non-hematologic toxicities than CF-treated patients and significantly fewer treatment-related deaths.

An unplanned non-inferiority analysis revealed that the mortality risk with CS decreased to a level that was determined by rigorous criteria to be non-inferior to the level achieved by the reference treatment (HR=0.92, p=0.0068).

The overall median survival in the 590 patients with diffuse-type histology was 9.0 months for CS patients and 7.1 months for CF patients, HR=0.83, p=.0413.

Dr. Ajani noted that the overall decline in the rate of gastric cancer in the U.S. applies to the intestinal type and added that the rate of the diffuse type has actually increased. In fact, data from 1973 through 2000 show that while the intestinal type decreased by 52% from 1973 through 2000, the diffuse type increased by 441% during that same period. Given the surge in diffuse-type gastric cancer, the results are particularly relevant, he said.

Gastric cancer is fourth most common malignancy worldwide and is the second most common cause of cancer-related deaths.

Written by Jill Stein
Jill Stein is a Paris-based freelance medical writer.
jillstein03(at)gmail.com
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