Combined modality staging of high risk rectal cancer.

The personal experience with the radiologic staging of high risk rectal cancer undergoing preoperative treatment is reported. 61 patients shown to be affected by locally advanced (T3-T4, N+with any T) rectal tumors on combined modality staging, underwent restaging 4-5 weeks after treatment. In all patients liver US, pelvic CT and colorectal enema were performed before and after treatment. In 22 patients with low rectal cancer transrectal sonography was performed. In 19 patients pelvic MRI was performed. The 61 patients were considered operable on second staging and thus referred to surgery. Subsequent control on histology has confirmed the diagnostic accuracy of the single procedures and of their combination. US was shown to be of high accuracy in the evaluation of T (90.8%) and of high predictive value for N. CT accuracy (84%) and MRI accuracy (78.9%) was lower because both tend to overstaging in the evaluation of T of rectal tumors undergoing preoperative treatment. Low CT accuracy (64%) and MRI accuracy (58%) was observed for N. There was optimum agreement between histology and imaging in the assessment of tumor shrinkage, well visualized by rectal enema which supported combined restaging with 88% accuracy for T.