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).
Study results were published in today’s issue of the Journal of the American Medical Association.
“This study will change standard practice across the country for postoperative treatment of this type of pancreatic cancer,” said principal investigator, William F. Regine, MD, 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.”
Gemcitabine interferes with the growth of cancer cells and belongs to a group of medicines called antimetabolites. The drug 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 median survival for patients who received gemcitabine was 20.5 months, compared to 16.9 months for patients who received the standard treatment. Researchers did not see any benefit of adding gemcitabine for patients with cancer in other parts of the pancreas.
Regine said 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. However, according to Regine, 70 percent of the patients in this study experienced 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,” Regine said.
RTOG researchers are already 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.
The four-year, multicenter trial was funded by the National Cancer Institute.