Dosimetry comparison between interstitial and intracavitary irradiation in the treatment of uterine cervix cancer.

Locally advanced carcinoma of the uterine cervix, and carcinoma of the cervical stump are managed primarily by endocurietherapy [ECT] combined with external-beam pelvic irradiation. Two afterloading techniques of endocurietherapy are used, first, the intracavitary technique with 137Cesium, and second, the interstitial technique with 192Iridium. Because of displacement of the bladder and rectum away from the applicator in intracavitary ECT, compared to interstitial ECT where vaginal packing cannot be used, the rectal and bladder reference point doses are much lower. The use of the interstitial endocurietherapy technique should be limited to specific presentations where the distorted anatomy does not permit good intracavitary dosimetry in cases of locally advanced cervical and cervical stump cancers. A higher risk of major bowel and bladder complications must be accepted in order to achieve local tumor control if the Transperineal Template 192Iridium Endocurietherapy is required and used.