Results Indicate that Adjuvant Chemotherapy Without Radiation Improves Survival

Long-Term Results Indicate that Adjuvant Chemotherapy Without Radiation Improves Survival in Pancreatic Cancer

According to results recently published in The New England Journal of Medicine, the delivery of chemotherapy after surgery for early pancreatic cancer substantially increases patient survival over surgery alone. In contrast, chemotherapy plus radiation (chemoradiation) following surgery does not appear to produce any survival benefit over surgery alone in these patients.

The pancreas is an organ that is surrounded by the stomach, small intestine, bile ducts (tubes that connect the liver to the small intestine), gallbladder, liver and spleen. The pancreas helps the body to break down food and produces hormones, such as insulin, to regulate the body’s storage and use of food. Surgery for pancreatic cancer is performed in order to remove the cancer and to gain information about its severity. Surgery can be performed with curative intent for some patients with cancer localized to the pancreas.

Many patients with early pancreatic cancer already have small amounts of undetectable cancer that has spread outside the pancreas that was not removed by surgery. These cancer cells are referred to as micrometastases and are responsible for relapses following treatment with surgery alone. Because micrometastases cannot be detected by any of the currently available tests, standard treatment often includes the use of adjuvant (therapy delivered after primary treatment) chemotherapy and/or radiation to try to eliminate these cancer cells.

Little research has been done to compare the effects of adjuvant therapies on survivability of early stage pancreatic cancer. Results from earlier studies evaluating differing adjuvant regimens have not been consistent. Thus, researchers from the European Study Group for Pancreatic Cancer conducted a clinical trial to evaluate adjuvant regimens in patients with early stage pancreatic cancer. Early results from this clinical trial were previously reported, and updated long-term results have recently been reported.
1,2 In this trial, 289 patients underwent surgery and then received chemotherapy consisting of 5-fluorouracil (5-FU) and radiation (chemoradiation), chemoradiation followed by additional 5-FU chemotherapy, 5-FU chemotherapy alone or no additional treatment (observation group).

Overall, survival at 5 years following surgery was significantly increased for patients who had received chemotherapy only; however, survival at 5 years was significantly reduced for patients who had received chemoradiotherapy only. The estimated survival rate at 5 years was 29% for patients treated with chemotherapy alone, 13% for patients treated with chemoradiotherapy plus chemotherapy, 11% for patients in the observation group, and 7% for patients treated with chemoradiation. The average duration of survival was 21.6 months for patients treated with chemotherapy, 19.9 months for patients treated with chemoradiation plus chemotherapy, 16.9 months for patients in the observation group, and 13.9 months for patients treated with chemoradiation.

These results suggest that adjuvant chemotherapy significantly increases survival over surgery alone in patients with operable pancreatic cancer, but adjuvant chemoradiation produces no benefit over surgery alone. In fact, chemoradiation alone appears to reduce 5-year survival and the duration of survival compared to surgery alone in this group of patients. Clinical trials are ongoing to evaluate more precisely delivered radiation and different chemotherapy regimens as adjuvant treatment to help define the clinical role of adjuvant therapy in patients with pancreatic cancer. Individuals diagnosed with pancreatic cancer may wish to discuss with their physician the risks and benefits of adjuvant chemotherapy.

References:

  1. Neoptolemos J, Stocken D, Friess H, et al. A randomized trial of chemoradiotherapy and chemotherapy after resection of pancreatic cancer.

The New England Journal of Medicine. 2004;350:1200-1210.

  1. The Lancet, Vol 358, No 9293, pp 1576-1585, 2001
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