Addition of Gemcitabine to Standard Therapy After Surgery Improves Survival for Pancreatic Cancer Patients
Philadelphia - March 4, 2008 - Adding the drug gemcitabine to standard chemoradiotherapy following surgery improved survival for patients with the most common form of pancreatic cancer, according to a new study conducted by the Radiation Therapy Oncology Groups (RTOG), a clinical research component of the American College of Radiology (ACR). RTOG investigators found that the new therapy was associated with a demonstrated survival benefit. However, since this improvement was not statistically significant the researchers concluded that new, more effective systemic therapies still are needed to prevent recurrence of this often-deadly disease.
The four-year, multicenter trial, funded by the National Cancer Institute (NCI), part of the National Institutes of Health (NIH), was the largest clinical study of its kind and the first phase III clinical trial in the United States in three decades to look at additional (adjuvant) treatment for pancreatic surgery patients. Results of the study, RTOG 9704, which focused on patients with pancreatic head adenocarcinoma, or cancer of the head (the wider part) of the pancreas, are published in the March 5 issue of the Journal of the American Medical Association (JAMA).
"This study will change standard practice across the country for postoperative treatment of this type of pancreatic cancer," says the principal investigator, William F. Regine, M.D., professor and chairman of radiation oncology at the University of Maryland School of Medicine and chief of radiation oncology at the University of Maryland Marlene and Stewart Greenebaum Cancer Center. "Although the results are not considered statistically significant, they are clinically meaningful. There was consistent improvement in survival among patients with cancers of the head of the pancreas who received gemcitabine, at least up to three years following diagnosis," Dr. Regine says.
Cancer of the pancreas 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 alive five years after they are diagnosed. Surgery is the treatment of choice, but less than 15 percent of patients are eligible because the disease is usually diagnosed at an advanced stage.
"RTOG has reported the study's preliminary results at major cancer society meetings and many oncologists are already using this new combination therapy with gemcitabine to treat patients post surgery," relates Walter J. Curran, Jr., M.D., the RTOG Group Chair, and the Lawrence W. Davis Professor and Chair of the Department of Radiation Oncology in the Emory School of Medicine and Chief Medical Officer of the Emory Winship Cancer Institute.
Gemcitabine interferes with the growth of cancer cells and belongs to a group of medicines called antimetabolites. It is also used to treat patients with advanced pancreatic cancer who are not eligible for surgery, as well as a number of other cancers. The randomized controlled phase III trial included 451 eligible and analyzable patients enrolled between July 1998 and July 2002 at 164 U.S. and Canadian institutions, with follow-up through August 2006
Thirty-one percent of the participants with pancreatic head adenocarcinoma were still alive three years after diagnosis following surgery and treatment with gemcitabine, another chemotherapy drug called 5-fluorouracil (5-FU) and radiation. That compares with a 22 percent three-year survival rate for patients who were treated with 5-FU and radiation alone after surgery - the standard postoperative treatment for this type of cancer since the 1980s.
The median survival for patients who received gemcitabine was 20.5 months, compared to 16.9 months for patients who received the standard treatment. Median survival is the point at which half of the patients in each group are still living. Researchers did not see any benefit of adding gemcitabine for patients with cancer in other parts of the pancreas.
Dr. Regine says that the treatment was well-tolerated, and patients in the study had the lowest rate of cancer recurring in its original location than in any previous study. The tumor came back in the same area in 23 percent of the patients, compared to 40 percent to 60 percent of patients in other studies. But, according to Dr. Regine, 70 percent of the patients in this study experienced spread of their cancer to other parts of the body, a process that is known as metastasis.
"Clearly, metastatic disease is a huge problem, and we need more clinical research to identify new systemic or targeted therapies to prevent this type of recurrence," Dr. Regine says. RTOG researchers already are planning to test new agents, using the new combination therapy of gemcitabine, 5-FU and radiation as the standard. They also will study the genetic profiles of these cancers to help determine how well patients will respond to a particular therapy, which would allow doctors to tailor the treatment to the individual patient.
In addition to the RTOG, two other NCI-funded cooperative groups, the Eastern Cooperative Oncology Group and the Southwest Oncology Group, were also involved in the study.
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