INTRAOPERATIVE IRRADIATION AFTER PALLIATIVE SURGERY FOR LOCALLY RECURRENT RECTAL-CANCER

Background, In patients with locally recurrent rectal cancer, long-ter m disease control and survival is uncommon with single-modality therap y. This report evaluates results achieved at the Mayo Clinic (Rocheste r, MN) with single- or combined-modality treatment, including intraope rative irradiation. Methods. From 1981 to 1988, 106 patients underwent palliative surgical resections at the Mayo Clinic for locally recurre nt rectal cancer. None had evidence of extra-pelvic disease, and 42 re ceived intraoperative electron beam irradiation (IORT) as a component of treatment. Gross residual disease remained after maximal surgical r esection in 34 of the 42 patients and 61 of the patients who did not r eceive IORT, The IORT dose was 15-20 Gy in 39 patients and 10, 25, and 30 Gy in the other 3. External beam irradiation (EBRT) was administer ed to 41 of the 42 patients (doses greater than or equal to 45 Gy to 3 8 patients). Results. Kaplan-Meier survival estimates at 3 and 5 years were analyzed for the 106 patients. Palliative surgical resection alo ne (12 patients) resulted in a 3-year survival of 8% and a 5-year surv ival of 0%. Statistically significant factors relative to survival bas ed on the univariate analysis of all patients included amount of resid ual tumor (microscopic vs. gross, P = 0.032) treatment method (P = 0.0 05), IORT versus no IORT (P = 0.0006), type of symptoms (P = 0.0075), type of fixation (P < 0.0001), and preoperative Eastern Cooperative On cology Group status (P = 0.03). For patients who received IORT, 3-year survival with gross residual tumor or presentation with pain was 44% and 43%, respectively. Factors not associated with survival (univariat e) included extended versus conventional surgical resection, grade, ag e, and sex. The 3-year cumulative probability of distant metastasis wa s 60% in the patients who received IORT and 54% in those who did not. The 3-year local relapse rates were 40% versus 93% in patients who rec eived IORT versus those who did not. Conclusions. Although the additio n of IORT to external irradiation and maximal surgical resection appea rs to improve local tumor control and survival in patients who undergo palliative surgical resection for locally recurrent rectal cancer, fu rther gains in treatment are necessary. Considering the high rates of distant metastasis, more routine systemic therapy with 5-fluorouracil (5-FU) leucovorin, 5-FU levamisole, or all three needs to be incorpora ted into aggressive treatment approaches. In patients with gross resid ual tumor after maximum surgical resection, local tumor control is ina dequate despite treatment combinations including IORT, The evaluation of radiation sensitizers or biologic modifiers during external irradia tion and IORT is indicated.