A Phase II Study of Extended Field IMRT External Beam Irradiation and Intracavitary Brachytherapy

Recent studies have shown that the chance of survival among women with advanced cervical cancer is increased when they receive concurrent chemotherapy and radiation to the pelvis. However, patients who have advanced disease show loco-regional failure as well as a high incidence of distant metastasis. Positron emission tomography (PET) scanning has high sensitivity and specificity in the detection of pelvic and para-aortic lymph node metastases. While the detection of para-aortic metastases by PET significantly impacts prognosis, PET has been known to show positive lymph node metastasis in the pelvis only while not detecting micrometastatic disease in the para-aortic lymph nodes (despite the fact that they are histologically known). In addition, patients with positive para-aortic lymph nodes on PET, greater amounts (more than 45 Gy) of radiation must be used to improve the probability of controlling the cancer. However, doses greater than this have been limited because of the dose and volume limits to the small bowel. But, Intensity Modulated Radiation Therapy (IMRT) is a new way of calculating and delivering radiation therapy. Compared to external beam radiation, IMRT has the improved ability to deliver large doses of radiation to specific targets while minimizing the exposure to surrounding normal tissue. With IMRT, however, the effective dose/volume can be increased more safely and lower the toxicity of surrounding tissue, thus making prophylactic dosing to para-aortic lymph nodes not detected by PET safer and more effective.