The researchers hoping to encourage a change in that standard report their comparison of the two methods in the July 1 issue of the International Journal of Radiation Oncology, Biology, Physics.
Like cervical cancer, vaginal cancer advances predictably, spreading to lymph nodes increasingly higher up in the body as the disease progresses. Doctors use information about the size of the tumor and the involvement of lymph nodes to determine treatment, such as where to target radiation and whether to use surgery or chemotherapy.
The results of this study suggest that the use of PET, or positron emission tomography, would make diagnosis of vaginal cancer much more accurate and allow better selection of treatment, according to study author Perry W. Grigsby, M.D., professor of radiation oncology and radiology.
However, until the procedure is reviewed and approved by the Centers for Medicaid and Medicare Services (CMS), vaginal cancer patients will most likely not be evaluated using PET scans.
CMS policies set standards often followed by private health insurance companies and therefore strongly determine what procedures physicians use. Studies such as this one play an essential role in CMS acceptance of new procedures.
"In 1999, we began publishing papers showing that PET scans picked up more cancerous lymph nodes in patients with cervical cancer," Grigsby says. "Armed with data from these kinds of studies, I went to Washington in 2003 to petition CMS to approve the use of PET scans for diagnosis of cervical cancer. In January of 2005, the procedure was approved for cervical cancer."