Adding the cancer-fighting drug gemcitabine to standard therapy after surgery significantly improves survival for patients with the most common form of pancreatic cancer, according to a new multicenter study led by a University of Maryland radiation oncologist.
The results of the four-year Phase III clinical trial were presented at the American Society of Clinical Oncology annual meeting in Atlanta.
More than 500 patients at 128 institutions across the country, including the University of Maryland Marlene and Stewart Greenebaum Cancer Center, were enrolled in the federally funded study from 1998 to 2002.
Thirty-two percent of study participants with "pancreatic head adenocarcinoma" (cancer of the head, or wider part, of the pancreas) were still alive three years after diagnosis after having surgery and being treated with gemcitabine, another chemotherapy drug called 5-fluorouracil (5-FU) and radiation therapy. That compares to a 21 percent three-year survival rate for patients who received 5-FU and radiation treatments alone following their surgery.
"The addition of gemcitabine to the standard postoperative treatment increased patients' survival by 50 percent, which is a significant improvement. We believe these findings will provide a new standard for treating patients with this devastating disease," says the principal investigator, William F. Regine, M.D., professor and chairman of the Department of Radiation Oncology at the University of Maryland School of Medicine and chief of radiation oncology at the University of Maryland Medical Center.
Dr. Regine adds that that the study will serve as a basis for additional research that may lead to more effective treatments for pancreatic cancer. Even with the new combination therapy, the median survival for patients in the study who received gemcitabine was 20.6 months compared to 16.9 months for the patients who had the standard therapy. Median survival is the point at which half of the patients in each group are still living.
Cancer of the pancreas, a large gland just behind the stomach that produces digestive juices and insulin, is the fourth leading cause of cancer death in the United States, with 32,000 people dying of the disease each year. Only 4 percent of people are still living five years after they are diagnosed. Surgery is the treatment of choice for long-term survival, but less than 15 percent of patients are eligible because the disease is usually diagnosed at an advanced stage.
Dr. Regine says that even after having surgery, patients often experience a recurrence of the cancer in the pancreas or in the liver, and treatment options are limited.
"Since the 1990s, the standard of care for patients who have had surgery has been postoperative treatment with the chemotherapy drug 5-FU and radiation. We wanted to find out if adding gemcitabine would boost survival for these patients," Dr. Regine says. He notes that the drug has been used as a first-line treatment for patients with advanced pancreatic cancer who are not eligible for surgery. Gemcitabine interferes with the growth of cancer cells and is used to treat cancer of the breast, pancreas and lung. It belongs to a group of medicines called antimetabolites.
Although the new combination therapy increased survival for patients with pancreatic head cancer, researchers did not see any benefit for patients with cancer in other parts of the gland. Eighty-five percent of pancreatic cancers are located in the head of the pancreas. Surgery to remove this type of tumor, along with the entire pancreas head, part of the small intestine and other nearby tissue, is called the Whipple procedure.
Researchers also found that although gemcitabine lowered patients' white blood cell counts, and consequently their ability to fight infection, oncologists could manage this side effect, and most of the patients were still able to complete the chemotherapy and radiation treatments.