Stereotactic body radiotherapy improves treatment response in metastatic colorectal cancer

This study investigated the effectiveness of stereotactic body radiotherapy (SBRT) in metastatic (spread to other parts of the body) colorectal cancer. Researchers suggested that SBRT is associated with improved tumor response and manageable side effects.

Colorectal cancer is the second most commonly diagnosed cancer in women and third in men. An early detection is associated with a 5-year survival rate of 93%. However, over 20% of patients present with metastatic disease at diagnosis.

Chemotherapy and surgery are the standard treatment for advanced disease. However, some patients might not be eligible for this treatment due to the nature of the tumor. A high number of patients are not eligible to receive the standard treatment. These patients must receive other forms of therapy such as radiation therapy.

SBRT consists of the delivery of very high radiation dose to a small area. Therefore, it has little effects on other body areas. Prior studies showed that SBRT not only kills the tumor cells but also may destroy all the tumor cells that may be left behind. However, it is still not clear how SBRT could help treat patients with metastatic colorectal cancer.

This study reviewed 15 other studies. 308 patients with liver metastases and 285 with lung metastasis were included. Patients were recruited over an average of 6 years.

In patients with liver metastasis tumor response rate was between 50 and 100% after 1 year of treatment, and 32 to 91% after 2 years. Overall survival ranged from 53% to 100% at 1 year and from 26% to 83% after 2 years after treatment.

For patients with lung metastasis, response rates were from 62 to 92% after 1 year and 53 to 92% after 2 years. Overall survival ranged from 65% to 76% after 2 years.

This study concluded that SBRT is associated with improved tumor response with manageable side effects in patients with colorectal cancer spread to the liver or lung.