Study Breaks New Ground in Treatment of Gastrointestinal Stromal Tumors (GISTs)
A Phase III clinical trial that included the University of Colorado Denver (UCD) School of Medicine and the University of Colorado Cancer Center demonstrated that an oral medication used in a leukemia treatment greatly improved the chances of recurrence-free survival in patients who had had a gastrointestinal stromal tumor (GIST) removed.
Results of the randomized study, which ran from 2002 to 2007, were published in the March 19 online issue of The Lancet. The study included more than 700 patients from 230 institutions in Canada and the U.S. with surgically removed GISTs, which generally originate in the small intestine or the stomach.
An important advance
UCD's Martin McCarter, MD, believes that the
GIST study is part of "a new paradigm in cancer
Martin McCarter, MD, associate professor of GI, Tumor and Endocrine Surgery at UCD and local principal investigator for the study, says that while GISTs affect only about 2,500 to 5,000 people a year in the U.S., the work produced an important advance in care for these patients.
Clinical researchers discovered that imatinib mesylate, an oral agent used to inhibit the growth of cancerous cells in patients with chronic myelogenous leukemia (a type of cancer originating in the blood cells of the bone marrow) also seemed to block diseased cell growth in patients with GISTs.
Imatinib mesylate and other new chemotherapeutic drugs, McCarter explains, aim to selectively block molecular pathways that trigger the growth of cancerous cells.
One group of patients received the drug, while a second group received a placebo. The study showed that at follow-up, the one-year recurrence-free survival rate for patients in the imatinib group was 98 percent, compared with 83 percent for patients in the placebo group.
Because of this gap, McCarter says, researchers stopped the study at an early interim analysis in 2007. On the basis of the study’s findings, in December 2008 the Food and Drug Administration approved the drug for "adjuvant therapy," treatments that come after a primary regimen is complete and that are designed to increase the chances of a cure. This treatment is now covered by insurance companies.
Researchers at UCD, the Cancer Center and other institutions are engaged in the enormously complex task of comparing the normal and mutated cells of cancer patients, and trying to figure out what changed and how.
"We need more detailed molecular analysis," McCarter says, "because there are potentially multiple cellular mutations that interact in complex ways. We're light years ahead of where we were 10 years ago in understanding them, but we're also probably light years away from where we want to be."
McCarter notes that UCD's role in the study's success benefits the School of Medicine and, by extension, University of Colorado Hospital and its Cancer Center. "Many people were responsible for the success of the trial," he adds, "including our research coordinators, my colleagues in Surgery and Medical Oncology and the willingness of so many patients to participate."
This page is adapted from a story that appeared in the UCH Insider, the hospital's candid e-newsletter. The Insider, which is published biweekly, is available to people outside the hospital via a free e-mail subscription. Tyler Smith (email@example.com) is managing editor of the Insider.