Study: Sentinel Node Biopsy Detects Spread of Colorectal Cancer

Japanese researchers report that the sentinel node biopsy, a more limited removal of lymph nodes that is increasingly used to detect spread of breast cancer, also appears to be an accurate way of detecting spread of colorectal cancer for patients with T1 or T2 tumors.

Lymph ducts usually drain to one lymph node first before draining through the rest of the lymph nodes in an area of the body. That first lymph node is called the sentinel lymph node. It can be identified by injection of a weak radioactive dye, and then removed and examined for cancer.

In a traditional lymph node dissection, surgeons take a number of lymph nodes and examine each one for cancer, resulting in a longer recovery period and the risk of long term complications and side effects.

In the study by researchers at Keio University in Tokyo, researchers identified sentinel lymph nodes in 51 of 56 patients who underwent surgery for colorectal cancer. They also performed a standard lymph node dissection for each patients, removing an average of 24 lymph nodes per patient.

They reported in the journal Diseases of the Colon and Rectum that the sentinel node was an accurate predictor of whether the cancer had spread for 47 of the 51 patients -- a diagnostic accuracy of 92 percent.

In 18 of the 22 patients whose cancer had spread to the lymph nodes, the sentinel node was positive, they reported. All four instances in which the sentinel node failed to detect the spread occurred in patients with advanced colorectal cancer and T3 primary tumors.

"The results suggest that sentinel node mapping and intraoperative biopsy may be a sensitive and specific diagnostic method for detecting metastasis in regional lymph nodes in patients with colorectal cancer," the researchers concluded.

Other Sources: Diseases of the Colon and Rectum