FDA approves imaging agent to detect spread of head and neck cancers

Cristina Rodriguez, MD

Refinements in surgical techniques have allowed us to select patients who are appropriate candidates for less extensive, and typically less morbid, surgical procedures with improved functional outcomes. These are exemplified by larynx-preserving surgical procedures, transoral robotic surgery, etc. One of the continued challenges is how to address the neck in patients with no radiographic or clinical evidence of disease.

Neck lymph node dissections have historically provided valuable information to clinicians regarding the patient’s pathologic stage and high-risk features for recurrence, and they play an important role in regional control of disease in patients treated with surgery. However, there is a population of patients who are ultimately found to have no evidence of metastases to the neck, and they are exposed to the added cost and morbidity of this procedure.

This technology holds promise for being able to identify patients who may be spared a neck dissection. Yet, there are a few issues that merit consideration.

First, one cannot overlook regional control as a very important oncologic outcome in these patients undergoing curative intent therapy. I would be curious to know what the oncologic outcomes of patients undergoing sentinel lymph node biopsy compare to those receiving elective lymph node dissection (END) alone. Perhaps a prospective comparison of END and sentinel lymph node biopsy may make sense, with endpoints of interest being oncologic outcomes, cost-effectiveness and patient-reported quality-of-life measures. 

Second, as in any curative-intent therapeutic approach, appropriate patient selection is key.

There have been published reports of the accuracy of sentinel lymph node dissection in early-stage oral cavity tumors (T1 and T2 disease). I am curious to see what the results are for patients with T3 to T4a disease (included in this study), and whether this technology ought to be used in these patients who routinely undergo elective lymph node dissection due to high risk of nodal involvement.

Wendell G. Yarbrough, MD, MMHC, FACS

The approval of Lymphoseek for head and neck cancers will make sentinel lymph node biopsy more available for patients with cancers of the upper aerodigestive tract. The sentinel lymph node biopsy technique for head and neck cancers is most useful for select patients with lower risk of nodal spread, when physicians are trying to avoid postoperative therapy (like radiation) and minimize the extent of neck node removal. One difficulty that is somewhat unique to head and neck cancers is that the site of the cancer that needs to be injected can be hard to reach for patients whose tumors are in locations other than the mouth.

Miriam N. Lango, MD

Tc-99-based sentinel lymph node mapping is a routine part of staging melanomas but remain investigational for early oral cancer. The technique has been studied most intensively in European centers, where it was found to be safe and accurate in detecting micrometastatic disease in oral cancer. Lymphoscintigraphy with sentinel lymph node biopsy potentially could replace elective cervical lymphadenectomy in approximately 70% of patients with early oral cancer. The FDA approval may enhance the adoption of the technology for head and neck cancers. However, adoption may be hampered by limited experience with the technique by some surgeons. Specialized centers that also treat melanoma are most likely to be early adopters.