High-dose-rate intraoperative brachytherapy for recurrent colorectal cancer

Management of locally recurrent colorectal adenocarcinoma represents a significant challenge. Many of these tumors adhere to or invade into vital pelvic structures rendering surgery or external beam radiotherapy (EBRT) as palliative treatment. Therefore, a treatment approach was developed to evaluate the role of high-dose-rate intraoperative brachytherapy (HDR-IORT) and surgery as a component of therapy in the management of locally recurrent colorectal cancer. This is an update of our preliminary report with longer follow-up and larger patient numbers.

Between January 1992 and September 1998, 74 patients with locally recurrent rectal cancer were treated with surgery and HDR-IORT. Additional EBRT was given to 29 patients, and 33 patients received 5-fluorouracil based chemotherapy. All patients underwent complete gross resection, and 21 of 74 had positive microscopic margin. The dose of HDR-IORT ranged from 10 to 18 Gy.

With a median follow-up of 22 months, the 5-year local control, distant metastasis disease-free, disease-free, and overall survival rates were 39%, 39%, 23%, and 23%, respectively. The only predictor of improved local control was a negative margin of resection with a 5-year local control rate of 43%, compared to 26% in those with positive margin (p = 0.02). For overall survival, a negative microscopic margin (p = 0.04) and the use of IORT + EBRT (p = 0.04) were significant predictors of improved survival. The incidence of peripheral neuropathy was 16%.

The results with HDR-IORT in this group of patients are encouraging. Further improvements in local and distant control are still needed.