Sentinel Node Biopsy in Head and Neck Cancer: No Easy Answer

(A video of sentinel node biopsy for melanoma is available as part of the supplementary material included with the publication of the randomized controlled melanoma trial. The video can be found at http://content.nejm.org /cgi/content/full/355/13/1307/DC1, or by going to the New England Journal of Medicine Web site.)

Sentinel Node Biopsies in Head and Neck Cancers

Jonas T. Johnson, MD

The use of sentinel node biopsy in nonmelanoma head and neck cancers is still under discussion. Here is the problem, said Jonas T. Johnson, MD, Professor and Chairman of the Department of Otolaryngology and Professor of Radiation Oncology at the University of Pittsburgh School of Medicine. In melanoma, where it has been validated as actually affecting outcome, they have been able to study it in thousands of patients. In head and neck cancer, it has only been studied in hundreds of patients. Preliminary evidence suggests that it may be useful.

It is unequivocally true that about 70% of people undergoing complete neck dissection are found to have no nodal metastases, so in retrospect you could say they didn’t need it. But you didn’t know that until it was done. And sentinel node biopsy is not sensitive enough yet to replace that, in my opinion, he said.

To determine just how sensitive the diagnostic procedure is in squamous cell head and neck cancer, the American College of Surgeons Oncology Group (ACOSOG) designed a single-arm trial to compare the rate of nodal metastases detected by sentinel node detection and by subsequent selective removal of level I, II, III, and IV nodes. Complete data have not been released from the trial, but Francisco J. Civantos, MD, Associate Professor of Head and Neck Surgery at the Miller School of Medicine at the University of Miami, who led the study, presented preliminary data at the Triological Society meeting in February. A total of 137 patients with T1 or T2 clinically node-negative oral cancers were enrolled at 25 institutions by 34 certified surgeons. Preliminary data indicated a 92% negative predictive value with the technique, meaning that 11 of the patients had a negative sentinel node biopsy but were found to have nodal metastases upon more extensive nodal resection.

Tumors on the floor of the mouth appear to be more problematic for sentinel node biopsy than do those on the tongue or elsewhere in the oral cavity. One problem is that such tumors can lie right on top of the nodal basin, which makes distinguishing sentinel nodes difficult during surgery due to radioactive shine from the primary injection site. Additionally, the lymphatic drainage is particularly complex in this area, said Randal S. Weber, MD, Chairman of the Department of Head and Neck Surgery and Professor of Surgery at the University of Texas M. D. Anderson Cancer Center in Houston. The floor of the mouth has a high incidence of cross-lymphatics, which drain to the opposite side, for example. Based on these observations, Dr. Weber is cautious about the use of sentinel node biopsy in squamous cell head and neck cancer. It doesn’t appear to produce the same consistency of findings as it does in cutaneous melanoma.