Combined chemotherapy and radiation therapy following surgery to remove stomach cancer can significantly extend survival rates compared with surgery alone.
That's the main finding of a clinical trial led by the Southwest Oncology Group, whose statistical center is located at the Hutchinson Center.
The study, one of the largest of its kind, indicates that patients at high risk for recurrence of adenocarcinoma of the stomach should be considered for post-operative therapy.
Dr. Jacqueline Benedetti, co-author of the paper and an investigator in the Public Health Sciences Division, said the study was notable both for its size and outcome.
"It can be difficult to get enough patients enrolled in this kind of trial," she said. "A big achievement was our ability to accrue enough patients and complete the study. In fact, because enrollment was more rapid than expected, we were able to increase our accrual goal, giving us a better chance to detect clinically important treatment effects."
The study involved researchers from hundreds of institutions around the country and appears in the Sept. 6 edition of the New England Journal of Medicine.
About 24,000 people in the United States each year are diagnosed with stomach cancer. While the 10-year survival rate among patients diagnosed at an early stage is about 65 percent, those with more advanced cancers fare poorly, with survival rates ranging from 3 to 42 percent. Because the disease presents ambiguous symptoms, most cases are diagnosed at an advanced stage.
Curative treatment of stomach cancer requires surgical removal of all or a portion of the stomach, a procedure known as gastrectomy.
Previous small-scale trials have suggested a potential benefit of radiation therapy and chemotherapy following surgery, prompting SWOG to initiate a larger, definitive study.
In the study, 556 patients who had undergone surgery for stomach cancer and were considered to be at high risk for disease recurrence were randomly assigned to a group that received surgery alone or surgery followed by postoperative treatment with chemotherapy and radiation. This type of study, which seeks to compare a new form of treatment with the current standard therapy, is known as a phase III clinical trial.
The median overall survival in the surgery-only group was 27 months, compared to 36 months in the chemoradiotherapy group, indicating that postoperative chemoradiotherapy should be considered for high-risk patients.
Future trials with patients who have undergone gastrectomy for stomach cancer likely will compare the adjuvant therapy tested in this study with other forms of post-operative therapy, Benedetti said.
"Planning meetings are already under way to figure out what's next," she said. "A lot of other new therapies on the horizon are of interest in treating stomach cancer, including agents that target molecular receptors important in the development of gastric malignancies."