WEDNESDAY, March 28 (HealthDay News) -- Extended treatment with the cancer drug Gleevec leads to improved survival rates in patients who have had surgery to remove a gastrointestinal stromal tumor and have a high risk of cancer recurrence, a new study says.

"Gastrointestinal stromal tumors are usually found in the stomach or the small intestine but can occur at any site along the gastrointestinal tract and rarely elsewhere within the abdominal cavity," according to background information in the study by Finnish researchers.

Treatment with Gleevec (imatinib) for a year after surgery has improved recurrence-free survival in patients, but disease recurrence is common during the first year after imatinib treatment stops, suggesting that one year of treatment may not be long enough.

The study compared outcomes among 200 patients who received 400 milligrams (mg) of imatinib per day for 12 months and 200 patients who received the same amount of medication for 36 months. The patients, all of whom were from Finland, Germany, Norway or Sweden, began taking imatinib within 12 weeks after surgery.

Rates of recurrence-free survival after five years were approximately 66 percent in the 36-month group and 48 percent in the 12-month group. Rates of overall survival after five years were 92 percent in the 36-month group and 82 percent in the 12-month group.

Patients in the 36-month group were more likely to stop taking imatinib than those in the 12-month group -- 26 percent compared to 13 percent. The reasons included patient preference and adverse side effects. Nearly all the patients in the study had at least one adverse side effect, most of which were considered mild.

The study appears in the March 28 issue of the Journal of the American Medical Association.

More information

The American Cancer Society has more about gastrointestinal stromal tumors.