Evaluating the efficacy of intraoperative radiotherapy for patients with locally advanced and recurrent colorectal cancer

The present review evaluates the results and complications of intra-operative radiotherapy (IORT) for the treatment of patients with locally advanced (stage III) and recurrent colorectal cancer (CRC).

Locally advanced CRC means that the cancer has spread beyond (invaded) the lining of the large intestine (colon and rectum) or has spread to the surrounding lymph nodes. In some of these patients, as well as in patients who had a recurrence (return of the cancer), surgery alone cannot remove the tumor completely. In cases like this, other therapies like radiation or chemotherapy can improve local control (eliminating the remaining traces of cancer) and survival rates. IORT is a type of radiotherapy, which takes place during the surgical resection of the cancer. Immediately after the surgeon removes the cancer, a single dose of radiation is delivered directly into the body parts affected by cancer. This way IORT eliminates the residual cancer cells left after resection, and spares healthy tissue of unnecessary irradiation.  

This study reviewed the available medical literature on the subject of IORT. Altogether, 3003 patients (1792 patients with locally advanced CRC and 1211 patients with locally recurrent disease) were included who received IORT between 1965 and 2011. The majority (98% of the locally advanced group and 80% for the recurrent group) of these patients had rectal cancer.

There was a 78% improvement in local control and a 67% increase in overall survival rate (the percentage of patients who have survived for a defined period of time) 5 years after IORT treatment. Additionally, patients treated with IORT had a 49% increase in disease-free survival rate (the percentage of patients who have survived for a defined period of time, with no evidence of the disease). On the other hand, IORT was associated with a 86% increased risk of wound complications (delayed wound healing, wound infections) compared to patients who did not receive this treatment.

In conclusion, this review showed that focal radiation given right after surgical resection substantially improves survival rates in patients with locally advanced and recurrent colorectal cancer. 

This review analyzed many studies, some of which were performed more than 40 years ago, when treatment options were less developed. The heterogeneity of methodologies used in these trials is the main weakness of this review.