In the largest single-institution retrospective study to date, researchers at Mayo Clinic Cancer Center have shown that giving patients both radiation and chemotherapy after completely removing invasive pancreatic cancer may improve overall survival rates.
The American Cancer Society reports that while the incidence of pancreatic cancer has decreased over the last few years, it remains the fourth most common cause of cancer-related death. Pancreatic cancer, which has a very poor prognosis, killed more than 32,000 people in the United States last year.
"We are constantly looking for ways to improve the prognosis of patients with cancers such as this," says Robert Miller, M.D., co-primary investigator and a radiation oncologist at Mayo Clinic. "Our findings show that surgery should be complemented by both radiation and chemotherapy for best results."
In the study, the team of surgeons, oncologists and radiation oncologists from Mayo's Arizona and Minnesota campuses examined the records of 472 consecutively-treated patients. The patients all had surgery with negative margins (some healthy tissue cut out around the cancerous cells), between 1975 and 2005, to remove pancreatic adenocarcinoma. They excluded patients who had metastatic cancer, tumors that could not be removed or were not removed entirely (positive surgical margins), or indolent (slow growing) tumor types.
Ultimately 454 patients were included in the final comparison of patients who received adjuvant therapy with those who had not. More than half (274) received concurrent radiation and chemotherapy following and 50 percent survived two years, with 28 percent surviving at least five years. The researchers report more than one-third (180) received no additional therapy after surgery, and the comparative survival rates were significantly less, at 39 percent and 17 percent in two and five years, respectively.
Additional chemotherapy after concurrent radiation and chemotherapy seemed to have an even greater effect on survival (61 percent and 34 percent survived two and five years), but only 28 patients received that combination, not enough for the researchers to draw a firm conclusion about its effectiveness.
Drs. Miller and Corsini and their fellow researchers think these findings are important to clinicians worldwide. "While long-term outcomes with pancreatic cancer are generally poor," Dr. Corsini says, "our findings show that including both chemotherapy and radiation following surgery may significantly improve patient survival rates."
Mayo currently uses a treatment strategy for most patients that includes a combination of radiation and chemotherapy after surgery.