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Five-year Survival Data from the Phase III CLASSIC Trial Show a 34% Reduction in Gastric Cancer Mortality

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Key Points

  • In the phase III CLASSIC trial, patients treated with XELOX experienced a 34% reduction in the risk of death vs surgery alone, which is higher than the 28% reduction reported after 3 years of follow-up.
  • The 5-year overall survival rate was 78% in the XELOX group and 69% in the surgery-alone group (P = .0029, log-rank test unstratified).
  • According to the investigators, adjuvant XELOX after D2 gastrectomy should be considered as a standard treatment for patients with operable gastric cancer.

For patients with advanced gastric cancer, treatment with chemotherapy after surgery can reduce the risk of cancer-related death by 34% over 5 years compared to surgery alone, researchers reported at the 15th ESMO World Congress in Gastrointestinal Cancer (Abstract 007), held July 3 to 6 in Barcelona.

Sung Hoon Noh, MD, PhD, a gastric surgeon from Yonsei University College of Medicine, Korea, presented 5-year follow-up from the phase III CLASSIC trial, which compared adjuvant XELOX (capecitabine [Xeloda] plus oxaliplatin) after D2 gastrectomy to surgery alone in patients with operable gastric cancer.

Study Details

CLASSIC was a multinational, open-label, randomized phase III trial performed in South Korea, China, and Taiwan. Patients with stage II to IIIB gastric cancer who had undergone curative D2 gastrectomy were assigned to adjuvant XELOX for eight cycles or surgery alone. The primary endpoint was 3-year disease-free survival.

The clinical cutoff date for the prospectively planned final 5-year efficacy analysis was in November 2012. At that point, 103 (20%) patients in the XELOX group and 141 (27%) patients in the surgery-alone group had died. This represented a 34% reduction in the risk of death with XELOX vs surgery alone (hazard ratio [HR] = 0.66, 95% confidence interval [CI] = 0.51–0.85, P = .0015 by stratified Cox regression analysis), which is higher than the 28% reduction previously reported after 3 years of follow-up.

The 5-year overall survival rate was 78% in the XELOX group and 69% in the surgery-alone group (P = .0029, log-rank test unstratified). In the analysis of disease-free survival, 139 (26.7%) patients in the XELOX group and 203 (39.4%) patients in the surgery-alone group had relapsed, developed a new gastric cancer, or died, representing a 42% reduction in the risk of an event with XELOX vs surgery alone (HR = 0.58, 95% CI = 0.47–0.72, P < .0001 by stratified Cox analysis). The 5-year disease-free survival rate was 68% in the XELOX group and 53% in the surgery-alone group (P < .0001, log-rank test unstratified).

Effective Adjuvant Therapy

“Surgery is the most important modality in gastric cancer treatment and in the past it was considered that gastric cancer could be cured by surgery alone, if the surgery was properly performed,” Dr. Noh said. “However, there has been controversy over whether surgery is enough in advanced disease. The new CLASSIC data clearly shows that a XELOX regimen administered after surgery prolongs the lives of patients with gastric cancer compared to patients who had surgery alone.”

The further benefits in cancer mortality risk compared to the earlier analysis are statistically significant and clinically highly relevant, Dr. Noh said. “There is no doubt that XELOX is an effective therapy in the adjuvant setting.”

The study also shows the importance of treatment with a multidisciplinary team of oncologists, he said. “This work was done by collaboration between surgeons and medical oncologists. To win the war on cancer, collaboration is one of most important virtues across disciplines.”

Mature Survival Data

Commenting on the study, ESMO spokesperson Andrés Cervantes, MD, PhD, Professor of Medicine at the University of Valencia, Spain, said that the new findings were very important because they report mature survival data.

“Many trials reporting the effect of postoperative chemotherapy after gastrectomy for gastric cancer patients have failed in finding a significant benefit in survival,” noted Dr Cervantes, who was not involved in the study. “This is a well designed trial.”

Although a meta-analysis published in recent years showed that chemotherapy after a surgical resection of gastric cancer improved survival, most single studies have been negative, Dr Cervantes noted. “Having a positive study in this setting with drugs that are available in any country in Europe or even worldwide is definitely important.”

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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