THE INFLUENCE OF SURGICAL MARGINS ON ADVANCED CANCER TREATED WITH INTRAOPERATIVE RADIATION-THERAPY (IORT) AND SURGICAL RESECTION

Intraoperative radiation therapy (IORT) hag been used successfully in the treatment of malignancies, alone and as an adjunct to surgical res ection. This study examined a single institution's experience with com bined IORT and surgical resection in the treatment of advanced cancer. The records of 41 consecutive patients undergoing intraoperative radi ation therapy (IORT) at the Fox Chase Cancer Center, from July 1987 th rough March 1990, were retrospectively reviewed. All patients had loca lly advanced disease, of whom 73% had failed previous multimodality th erapy and 44% had undergone prior radiation therapy (XRT). The 2-year actuarial survival for the entire.cohort was 72%. Disease-free surviva l was 47% at 1 year and 5% at 2 years. The only important prognostic f actor predicting outcome was status of the surgical margin. Positive s urgical margins decreased the 2-year actuarial survival from 100% to 5 9%, and increased the local failure rate from 21% to 52%. Margin statu s had no effect on the later development of metastatic disease. Higher IORT doses, field sizes >7 cm, and multiple IORT fields were used for larger tumors and larger amounts of residual disease. These parameter s alone did not correlate with improved local control. This analysis s uggests the usefulness of aggressive surgical resection with IORT in e xtending survival for locally advanced or recurrent cancer. Negative m argin status is the best predictor of a favorable outcome and should b e used to select patients who may benefit from IORT. The use of radiat ion sensitizing agents should be explored in patients with positive ma rgins, since in-field failure continues to be the major pattern of fai lure. IORT in conjunction with aggressive surgical resection should co ntinue to be studied in prospective randomized clinical trials.