Better Lymph Node Staging For Colorectal Cancer

Techniques that identify the key lymph nodes and the lymph channels that drain areas of the colon or rectum where cancer is located can identify more patients with lymph nodes that contain cancer. Patients with nodes positive for cancer - stage III diagnosis -benefit from chemotherapy.

Patients who don't have positive nodes - stage II - have less benefit from chemotherapy and deciding whether the risk outweighs the benefit is difficult for both doctors and patients.

Because it is important to make sure that the staging is accurate, better techniques to locate lymph nodes and test them for cancer may find patients who are need to have their cancer upstaged from stage II to stage III and be treated with chemotherapy after their surgery.

Using a technique called lymphatic mapping along with identification of sentinel nodes, surgeons at the John Wayne Cancer Center in California found that 1 in 4 stage II patients had cancer that had spread to very small lymph nodes and were actually stage III.

Surgeons were able to locate sentinel nodes in almost all patients. Pathologists located the rest. Dye was used to stain the sentinel nodes and their lymphatic channels during surgery so that small nodes could be found and tested during the pathological examinations after surgery critical to accurate staging.

Anton Bilchik, M.D., Ph.D. and colleagues reported their research findings in the June 2005 Archives of Surgery. They concluded:

In a multicenter trial, ultrastaging of colon cancer is feasible and accurate. In stage II CRC, 24% of patients had nodal carcinoma cells not detected by conventional staging methods. Surgical technique (adequate lymph node retrieval) and focused pathological analysis may improve staging accuracy and the selection of patients for chemotherapy. The unnecessary toxicity and expense of chemotherapy may be avoided in those patients who are truly node negative.

Bilchik et al. Arch Surg. 2006;141:527-534.



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