Oral Abstract Presentations

Purpose/Objectives: Cervical cancer patients with disease extending laterally into parametrial tissue often require interstitial trans-perineal implantation under general anesthesia and a hospital stay for brachytherapy treatments. A major disadvantage of intraoperative implantation is the lack of 3D image guidance during needle placement. Here, we describe real-time CT-guidance to allow interstitial implantation of catheters with the Utrecht Fletcher Applicator® (NucletronTM) in an ambulatory setting. Materials/Methods: Following a mild oral analgesic and an anxiolytic, patients are placed on the CT simulator couch in the treatment position. The Utrecht tandem and ovoid (T&O) is inserted and a CT scan of the pelvis performed to confirm appropriate geometry. Delineating the extent of disease and organs at risk on the CT scan allows determination of the optimal number, distribution, and depth of insertion of each interstitial catheter. A CT is repeated after insertion of each catheter and adjustments are made in real time. Once all interstitial catheters are implanted, a final CT is performed for 3D optimization brachytherapy planning. Without movement or manipulation, the patients are then treated with HDR brachytherapy on the CT simulator couch. Following therapy, the Utrecht T&O applicator and interstitial needles are removed and patients are discharged home. Results: A total of 77 treatments were performed in 18 patients. Ten out of eighteen patients (56%) required 2 or fewer needles placed to adequately dose the extent of disease. Persistent vaginal bleeding after removal of the applicator was observed in 4 patients necessitating an inpatient stay for close observation with 2 patients requiring blood transfusions. Only one did not continue with the interstitial implantations and was treated with standard T&O implant followed by an external beam parametrial boost. All other patients tolerated the treatments well with no complications documented. Conclusions: Real-time CT-guided administration of interstitial catheters using the Utrecht applicator allows for proper positioning into parametrial disease. These implants are tolerated well and can be performed safely in an outpatient setting, obviating the need for placing interstitial needles in the operating room without 3-D image guidance.