Cancer Research Lab

Combined radiation and chemotherapy following the complete removal of invasive pancreatic adenocarcinoma can prolong patient survival for years, according to the results of a retrospective study presented Saturday at the 2007 Gastrointestinal Cancers Symposium in Orlando, Florida.

“There is no standard of care for patients with pancreatic cancer,” presenter Dr. Michele M. Corsini, from the Mayo Clinic in Rochester, Minnesota, said. “It is a very aggressive cancer that metastasizes early.”

To better understand how to optimize the prognosis of patients with pancreatic cancer, a team of surgeons, oncologists, and radiation oncologists conducted a retrospective study of patients who underwent complete resection at their institution in hopes of a cure.

“Our protocol is based on a study published in 1985 by the GI Tumor Study Group, where in the setting of margin-negative resected pancreatic cancer, we offer the combination of chemotherapy and radiation therapy,” Dr. Corsini explained.

“Between 1975 and 2005, there were 472 patients who had good surgery (results), with negative margins and no evidence of cancer at all,” she added. “For nine of them, by the time they returned for follow-up - within weeks — they already had metastatic disease.” Three others were lost to follow-up, and nine had adjuvant chemotherapy only.

The final analysis included 180 patients who received no adjuvant therapy; 246 who had radiation and chemotherapy; and 28 who received radiation and chemotherapy followed by another course of chemotherapy.

The patients usually started combined radiation and chemotherapy by 6 weeks after surgery. According to the presenters’ meeting abstract, the median radiation dose was 50.4 Gy in 28 fractions, and 98% of patients were also treated with concurrent 5-fluorouracil.

The median overall survival was 1.6 years among those who received no adjuvant therapy (n=180); 2.1years among those who received radiation and chemotherapy (n=246); and 2.9 years among those treated with radiation and chemotherapy plus a second round of chemotherapy (n=28). After 5 years, the overall survival was 17%, 28% and 34%, respectively.

“The patients who had disease in the local lymph nodes and high-grade tumors especially benefited from chemoradiation, even though you’d think they would have more chance of metastatic disease or dying sooner,” Dr. Corsini said. “But if you gave them radiation and chemotherapy, they lived even longer than those who were just observed.”

Those forgoing had fewer adverse prognostic factors, the oncologist continued. “Not as many had disease in the lymph nodes; not as many had high-grade tumors; and not as many patients had tumors that extended outside the pancreas. They were the best performers, which is probably why they were not offered radiation and chemotherapy. But ultimately, unfortunately, they did the worst.”

These findings reinforce the Mayo clinics’ current standard of care of offering adjuvant chemotherapy and radiation therapy to their patients with resected pancreatic cancer.

One thing has changed in recent years at the Mayo Clinics, based on the most up-to-date research. Since about 2003, gemcitabine has been offered to these patients, Dr. Corsini said. “Now patients generally get a couple cycles of gemcitabine starting at about 2 to 4 weeks after surgery, then radiation and 5FU at the same time for 5.5 or 6 weeks, then gemcitabine on its own again.”