Preliminary results from a University of Pittsburgh study evaluating extended-field intensity-modulated radiation therapy (IMRT) for cervical cancer found that it resulted in significantly reduced side effects and outcomes comparable to standard radiotherapy. The findings were presented today at the 48th Annual Meeting of the American Society for Therapeutic Radiology and Oncology (ASTRO) in Philadelphia.
"We have been limited in our ability to treat women with cervical cancer with optimal doses of radiotherapy because of debilitating side effects that greatly impact their quality of life," said Dwight E. Heron, M.D., study co-author and associate professor of radiation oncology, University of Pittsburgh School of Medicine. "Our study demonstrates that with IMRT, we can target high-energy beams directly to the tumor site and the areas of concern where the cancer cells may travel, resulting in less side effects and enabling us to give a full therapeutic dose."
Extended-field radiotherapy (EFRT) is the method of radiotherapy used with advanced cervical cancer in which the pelvis and abdominal region are irradiated to destroy cancer cells that travel up to the abdominal lymph nodes that drain from the tumor. According to Dr. Heron, standard EFRT causes serious side effects in as many as 40 percent of patients. These side effects can include frequent urination and pain, diarrhea and bowel obstruction and tend to worsen when chemotherapy is given at the same time as radiotherapy.
In the current study, 36 patients with cervical cancer were treated with extended-field IMRT and the chemotherapy agent cisplatin to determine the efficacy of treatment and treatment-related side effects. Of these patients, 34 had a complete response to treatment. Only two patients developed higher-grade gastrointestinal and urinary side effects and 10 developed myelotoxicity, a slowdown of blood cell production that is common with chemotherapy. The overall survival rate at two-year follow-up was 54 percent.
"We found that by using extended-field IMRT and chemotherapy, we were able to effectively reduce the toxic effects of treatment," said Sushil Beriwal, M.D., principal investigator and assistant professor at the University of Pittsburgh School of Medicine and medical director of radiation oncology at Magee-Womens Hospital of UPMC. "This is important because it means there are less treatment interruptions and more patients are able to complete the treatment within the prescribed time period. This, in turn, increases the efficacy of treatment, giving us encouraging evidence that these cervical cancer patients can benefit from IMRT."
Unlike standard radiation therapy, IMRT administers a radiation field that consists of several hundred small beams of varying intensities that pass through normal tissue without doing significant damage but converge to give a precise dose of radiation at the tumor site. IMRT can potentially limit the adverse side effects from radiation while increasing the intensity of doses that can be given to effectively destroy cancer cells.
Co-authors of the study include Greg Gan, Joseph L. Kelley, M.D., and Robert P. Edwards, M.D., all with the University of Pittsburgh School of Medicine.
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