The research was led by Yun Shin Chun, a surgical oncologist at Fox Chase Cancer Center in Philadelphia, and was performed on patients with pancreatic adenocarcinoma, the most common form of pancreatic cancer. It showed that those sufferers who receive the strongest anti-tumor benefit from preoperative radiation and chemotherapy survive an average of four times longer than those who receive little benefit.
The finding, Chun said, suggests other avenues of research on the biochemical pathways of the disease that may lead to additional treatment discoveries.
The Fox Chase Cancer Center has a history of research on cancer of the pancreas, a crucial organ situated behind the stomach that provides the body with essential hormones and enzymes. The malignancy is rarely discovered at an early stage, which sharply reduces the chances of effective treatment and patient survival. In 1986, the Center was the first to use “multimodal” therapy (in which two or more treatments, such as chemotherapy and radiation, are used at once) on pancreatic cancer prior to surgery. The Center also experimented, in the 1990s, with the drug gemcitabine to determine a safe dosage. The medication is now widely used to treat the condition.
In the most recent Fox Chase study, Chun and his team were guided by findings on other cancers to consider whether a patient’s response to preoperative treatment is a predictor of improved survival in cases of pancreatic adenocarcinoma.
“For many cancers—breast, esophagus, stomach, and colorectal liver metastases [cancers in which a tumor has spread to other organs]—it has been shown that survival is much better in people who have a good pathologic response to preoperative therapy—meaning that many tumor cells are killed—than in people who do not have a good pathologic response,” Chun said. “But this has not been established in pancreatic cancer; previous studies have shown conflicting results.”
The Fox Chase researchers examined tissue data from 135 pancreatic adenocarcinoma patients who received preoperative therapy and then surgery. The team’s chief pathologist inspected samples of the patients’ tumors after radiation/chemotherapy and determined whether the response to the therapy was minor, partial, or major, based on the degree of fibrosis (scarring) in the cancer tissue. Those patients classified as having had a major response to the therapy had a median survival rate of over five years. Those with a minor response survived only seventeen months.
Major responses unfortunately occur only 19 percent of the time, according to the doctors. But the results still provide investigators with important information for future research.
“Going forward,” said Chun, “if we can identify molecular factors in tumors associated with a major pathologic response, then we can make important progress in this disease.”