At the meeting Prof Sung Hoon Noh, a gastric surgeon from Yonsei University College of Medicine, Korea, presented 5-year follow-up from the phase III CLASSIC trial, which added combination chemotherapy to a standard surgical procedure called D2 gastrectomy. The chemotherapy regimen studied in the trial is called XELOX, which is a combination of the drugs capecitabine and oxaliplatin.
CLASSIC was a multinational open-label randomised phase III trial performed in South Korea, China and Taiwan. Patients with stage II-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 cut-off 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 versus surgery alone, which is higher than the 28% reduction previously reported after three years of follow-up.
"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, Prof 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, Prof Noh 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."
Commenting on the study, ESMO spokesperson Andrés Cervantes, Professor of Medicine at the University of Valencia, Spain, said 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," notes 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."