IMPROVED TREATMENT PLANNING FOR THE SYED-NEBLETT TEMPLATE USING ENDORECTAL-COLI MAGNETIC-RESONANCE AND INTRAOPERATIVE (LAPAROTOMY LAPAROSCOPY) GUIDANCE - A NEW INTEGRATED TECHNIQUE FOR HYSTERECTOMIZED WOMEN WITH VAGINAL TUMORS

The Syed template (Alpha-Omega Services, Bellflower, CA) represents an advance in interstitial gynecologic brachytherapy; however, its appea l is diminished by inaccuracies in target definition secondary to subo ptimal imaging of gynecologic tumors and the risk of viscus perforatio n during a ''blind'' procedure. Magnetic resonance (MR) scanning with an endorectal coil and computed tomography were studied as a possible tool to improve target definition and maximize treatment planning with Syed templates. Abdominopelvic contents could be visualized directly through a laparotomy incision or indirectly with a laparoscopic video display to allow further target definition and minimize complications associated with blind procedures after hysterectomy. The synthesis of these techniques with Syed template applications was attempted to pote ntiate the utility of this brachytherapy system. Five patients with ap ical vaginal tumors which arose after previous hysterectomies (two end ometrial cancer recurrences, one recurrent uterine sarcoma, two primar y vaginal cancers) were referred for radiotherapy. In three cases, ext ernal beam pelvic radiotherapy (median dose, 45 Gy; range, 45-50.4 Gy) was delivered initially. In all cases, the Syed applicator was used f or the brachytherapy component of the treatment. In two cases, high-re solution MR images (400 x 400 mu m) of the vaginal apex were obtained after insertion of an endorectal surface coil. The images defined the relationships between the template, target volume, bladder, rectum, an d intestine. The other three cases were planned with computerized tomo graphy (CT). In all cases, intraoperative examination of the abdominop elvic contents was provided when laparotomy and/or laparoscopy was per formed by the surgical team. The median brachytherapy dose prescribed to the isodose envelope covering the target volume was 40 Gy (range, 3 1-50 Gy). In all cases,the target volumes could be encompassed by the 60 cGy/hr isodose line. Tumor volume estimation was better with MR tha n CT. Procedure time was shorter with laparoscopy than with laparotomy . In two cases, bowel displacement was performed (one tissue expander, one omental sling) to prevent viscus perforation by interstitial need les. Four of five patients responded completely to the treatment. In t hree cases, local control was maintained at a median follow-up of 11 m onths. In conclusion, endorectal coil MRI may be advantageous to CT of the pelvis in that it allows preplanning to be achieved with greater precision and with less planning time. Major intraoperative complicati ons (i.e., perforation of hollow viscus organs) can be avoided when th e course of interstitial catheters is visualized from above by the sur gical team. The integration of these innovative techniques with an eff ective brachytherapy system has the potential of improving control and reducing complications when treating challenging gynecologic tumors. (C) 1995 Academic Press, Inc.