Surgical resection and high dose rate intraoperative radiation therapy for locally recurrent rectal cancer

Long-Term Survival After High-Dose-Rate Brachytherapy for Locally Advanced or Recurrent Colorectal Adenocarcinoma

BACKGROUND

We evaluated outcomes of intraoperative radiotherapy delivered with focal high-dose-rate (HDR) brachytherapy [intraoperative radiotherapy (IORT)] in the management of locally recurrent (LR) and locally advanced (LA) primary T4 colorectal carcinoma (CRC). LR CRC or LA primary disease is a clinical challenge due to the difficulty in obtaining negative margins after radical surgery and the high risk of subsequent recurrence. Few data exist on long-term outcomes of patients treated with surgery and HDR-IORT for LR or LA primary CRC.

METHODS

Three hundred CRC patients underwent HDR-IORT to the pelvis with gross surgical resection during November 1992-December 2007. Median follow-up for surviving patients was 53 (range 5-216) months. Eighty-eight patients (29 %) were treated for LA primary and 212 (71 %) LR disease. HDR-IORT was delivered using an iridium-192 remote afterloader and a Harrison-Anderson-Mick applicator. Median IORT dose was 1,500 (range 1,000-2,000) cGy.

RESULTS

Five-year overall survival probability was 49 %. Positive margin status was associated with inferior overall survival and disease-free survival. Competing-risks analysis for time to local failure and distant metastases identified a 5-year cumulative incidence of local failure and distant metastases of 33 and 47 %, respectively. Five-year cumulative incidence of local failure was 22 % for the LA group and 38 % in the LR group. Five-year probability of disease-free survival was 48 and 31 % for LA and LR patients, respectively, and 5-year probability of overall survival was 56 and 45 % for LA and LR patients, respectively.

CONCLUSIONS

HDR-IORT combined with resection results in encouraging local control rates with acceptable toxicity for patients with locally aggressive CRC.

Multidisciplinary management of patients with advanced rectal cancer

The chance of lymph node involvement in T(3) and T(4) rectal cancers is 20% to 60%, a risk sufficiently high that most clinicians favor mesorectal excision rather than less aggressive approaches. Patients who have a complete clinical response of the primary lesions to neoadjuvant therapy may represent a special case. Total mesorectal excision can be accomplished without sacrifice of the anal sphincters, and continence can be preserved. Evolving understanding of patterns of tumor spread and mechanisms of anal continence have resulted in increased use of continence-preserving procedures. Removal of the anal sphincters seems to be advantageous only if the sphincters are directly involved. A few small series suggest that a segmental sphincter resection could result in good local control and continence preservation, even if the sphincters are involved. Areas of controversy currently include the role of neoadjuvant therapy for high rectal lesions, the role of lateral lymph node dissection, and methods of improving anal continence after rectal resection.