School of Medicine researchers have shown that highly targeted radiation therapy improves survival and lessens treatment-related complications in cervical cancer patients.
The technique, called intensity-modulated radiation therapy (IMRT), is widely accepted for treating many cancers of the pelvic region, head and neck, and central nervous system, but the use of IMRT for cervical cancer is not as common. This is the first large study to show its effectiveness as a primary therapy for cervical cancer.
“Previous studies of IMRT for cervical cancer have been small with limited follow-up, and some used IMRT as a postoperative treatment instead of as primary therapy, but this evidence did suggest that IMRT could be an effective treatment choice,” said lead author Elizabeth Kidd, M.D., a Barnes-Jewish Hospital resident in the Department of Radiation Oncology.
Kidd and her colleagues, including researchers with the Siteman Cancer Center, report their findings in an upcoming issue of the International Journal of Radiation Oncology, Biology, Physics.
In the United States, cervical cancer is the third-leading cause of cancer death among women aged 15-34 and the fifth-leading cause of cancer death among women aged 35-54.
IMRT is an advanced mode of radiotherapy that allows the radiation dose to conform more precisely to the three-dimensional shape of the tumor. IMRT minimizes the dose to surrounding normal tissues and organs.
The study included 452 patients with newly diagnosed cervical cancer who were treated with external-beam radiation therapy. More than 80 percent of the patients received concurrent cisplatin, a chemotherapy drug commonly used for cervical cancer. The patients also received brachytherapy, in which a radioactive source is placed close to the cervical tumor.
From 1997-2005, 317 patients were treated with traditional whole-pelvic external-beam radiation.
After March 2005, the department changed its treatment policies so that all cervical cancer patients received radiation using IMRT, and 135 patients were treated until the study ended in September 2008.
“Our IMRT protocol was designed to replicate the traditional approach in the amount of radiation going to the tumor and pelvic lymph nodes, which is the first area where the cancer spreads,” Kidd said. “In the IMRT group, we expected to see a reduction of radiation-induced side effects in adjacent normal tissues, but we expected that both approaches would result in equivalent control of the cancer. We did see fewer treatment-related complications in the IMRT group, but we were surprised that the IMRT group also had better overall survival.”
At the time of most recent follow-up, 67 percent of IMRT patients were alive with no evidence of disease compared with 49 percent of non-IMRT patients. Within the same time period, less than 4 percent of IMRT patients had died of cervical cancer, while 37 percent of non-IMRT patients had died of cervical cancer.