Stereotactic body radiation therapy in patients with pelvic recurrence from rectal carcinoma

Objective: To investigate the clinical applications of stereotactic body radiation therapy (SBRT) using the CyberKnife system for pelvic recurrence from rectal cancer with a focus on survival and toxicity. Methods: Between 2002 and 2006, 23 patients with recurrent rectal cancer were treated with SBRT at our institution. The median follow-up was 31 months. Sites of recurrence were pre-sacral in seven patients and the pelvic wall in 16. SBRT doses ranged from 30 to 51 Gy (median 39 Gy) and were delivered in three fractions. Response to treatment was assessed by computed tomography. Overall and local progression-free survival and toxicities were recorded. Results: Four-year overall survival and local control rates were 24.9 and 74.3%, respectively. No prognostic factor was found to affect patient survival or local progression. One patient developed a severe radiation-related toxicity, but recovered completely after treatment. Conclusion: SBRT for pelvic recurrence was found to be comparable with other modalities with respect to overall survival and complication rates. Further studies are needed to confirm these preliminary results.