SKULL BASE TUMOR VOLUME AND SURGICAL MARGINS - A PILOT-STUDY

The relationship between preoperative assessment of tumor volume and o ncologic adequacy of surgical margins was studies retrospectively. Our hypothesis was that the risk of inadequate, or positive, margins woul d rise with increasing tumor volume and that this would adversely affe ct survival. We anticipated that limitations of surgical approaches us ed until 1988 would be reflected in an increasing proportion of positi ve margins with increasing tumor volume. We conducted a pilot study of 25 patients with malignant tumors of the anterolateral cranial base o perated on at the university of Pittsburgh Center for Cranial base sur gery between 1987 and 1988. Preoperative computed tomography assessmen t of tumor volume was performed in all patients, and correlation betwe en tumor volume, surgical margins, and survival was examined. Follow-u p interval averaged 31.7 months. Twelve histologic tumor types were re presented, with squamous cell carcinoma the most common (eight patient s [32%]). Tumor volume ranged from 0.9 to 390 cc, with a median of 48 cc. Based on a median split of tumor volumes, patients were classified as high volume (more than 48 cc) or low volume (less than 48 cc). Of patients in the high volume group, 92% were found to have positive sur gical margins, whereas only 50% of patients in the low volume group ha d positive margins. Analysis of the effect of tumor volume and surgica l margins on survival was limited by sample size constraints, but both high-tumor volume and positive margins tended to reduce patient survi val (0.07 < p 0.10).