부산대학교 도서관

Purpose/objective(s): A data registry was established upon implementation of a program of intra-operative radiation therapy (IORT) using high-dose rate brachytherapy. We evaluated the initial experience of patients with locally recurrent gastrointestinal (GI) cancers to help inform future patient selection and optimal multi-modal treatment management.Materials/methods: All patients treated with surgical resection and IORT at a tertiary referral center were prospectively enrolled in a registry after program implementation in 2015. Candidates for IORT included patients who presented with disease likely to be resected with either close or positive margins based on multi-disciplinary evaluation. Patient, disease, and treatment characteristics including radiation history and acute (within 90 days, Clavien-Dindo grade) were recorded. IORT was administered using a HAM applicator, with field size and location determined intra-operatively, prescribed to 1 cm depth with lead blocking as appropriate. Patterns of failure and toxicity were analyzed. Time to event analysis was conducted using Kaplan Meier method, and contingency tables and chi square statistics evaluated differences in frequency of events.Results: Twenty-one patients were identified with locally recurrent GI cancer (rectal 62%, colon 29%, and anal cancer, 9%) who underwent surgical resection and IORT with curative intent. Median age was 58 years. All patients had a history of pelvic external beam radiotherapy (EBRT, median 50.4 Gy); 9 (43%) were treated with pre-operative reirradiation (median dose 43 Gy, median 2 mo prior to surgery). The median IORT dose was 12.5 Gy (range 10-15). Resection was pathologically complete (R0, n = 9), or with microscopic (R1, n = 11) or macroscopic residual (R2, n = 1). Median follow up was 20 months. Twelve (57%) patients had failure at the site of IORT, at a median 7 mo. Freedom from failure (FFF) within the IORT field was associated with resection status (FFF-1y 75% for R0 vs 15% for R1/2, P = 0.0065) but not re-irradiation EBRT or IORT dose (P > 0.05). Pelvic failure beyond the IORT site occurred in 5 (24%) patients at a median 5 mo, and 13 (62%) had eventual distant metastases, at a median 5.5 months. Ultimately, only 3 patients (14%) were disease free at last follow-up. The median hospital stay was 6 days, the 90-day readmission rate was 25%, and acute grade 3 toxicity was observed in 43%, with abscess/sepsis most common (n = 5, 24%). Grade 3 toxicities and 90-day admission were not associated with resection status or EBRT (all P > 0.1). There were no 90-day grade 4/5 toxicities.Conclusion: In patients treated with surgical excision and IORT for locally recurrent GI cancer, the ability to achieve a clear resection margin is a critical determinant of in-field local control. Patient selection should consider the chance for R0 resection, as well as the risk of regional or distant progression, when evaluating patients for this aggressive multi-modal treatment.