Could Use of Lymphoseek Reduce Neck Dissection?

Fran Lowry

February 18, 2015

The radioactive tracer technetium 99mTc-tilmanocept (Lymphoseek, Navidea Biopharmaceuticals) is poised to become a viable alternative to elective neck dissection, the current gold standard for patients with head and neck cancer, according to European researchers.

In a previous study of patients undergoing surgical treatment for oral cavity squamous cell carcinoma with clinically negative neck, the false-negative rate with 99mTc-tilmanocept was 0% and the negative predictive value was 100%, as reported by Medscape Medical News.

Now, a European open-label trial of the tracer, presented at the 5th International Conference on Innovative Approaches in Head and Neck Oncology (ICHNO) in Nice, France, has yielded similar results.

Dr Remco de Bree

"Until recently, surgeons had little choice but to carry out en bloc surgery of all the soft tissue in a lymph node region, with all the after-effects that this entailed for the patient," explained lead researcher Remco de Bree, MD, from the VU University Medical Center in Amsterdam.

"Sentinel node detection and biopsy in early oral cancer has a high accuracy, in terms of sensitivity and negative predictive value, to detect occult metastases in clinically negative necks but not in all sites in the oral cavity," Dr de Bree told Medscape Medical News.

"For example, in floor of the mouth carcinoma, the accuracy is significantly lower because of what we call the 'shine-through phenomenon,' where radioactivity at the injection site and the sentinel node are difficult to separate because of a close spatial relation. Therefore, using conventional tracers may be difficult for some tumor sites," he explained.

"Our current multicenter pivotal study has shown that in many patients, by using a radiotracer with a novel receptor-based mechanism, the sentinel node can be reliably identified and removed for biopsy without having to undertake more extensive surgery. This means that only patients with metastatic sentinel nodes would require extensive surgical treatment," Dr de Bree said.

In their study, he and his colleagues compared the false negative rate of sentinel node biopsy between 99mTc-tilmanocept and postoperative nodal pathology.

The 101 patients had T1 to T4 head and neck squamous cell carcinoma. All underwent elective neck dissection, were injected with 99mTc-tilmanocept 50 µg the day of surgery or the day after, and underwent preoperative imaging.

The detection rate was 98%, the sensitivity was 97%, and the negative predictive value was 98%.

The use of 99mTc-tilmanocept for intraoperative lymphatic mapping in patients with breast cancer and melanoma was approved by the by the US Food and Drug Administration in 2013; for patients with head and neck cancer, it was approved in 2014. Its use in patients with breast cancer, melanoma, and head and neck cancer was approved by the European Medicines Agency in 2014.

The results of this trial "are not entirely new, but they may support a change in practice related to neck dissection," said Daniel Zips, MD, from Tübingen University in Germany, who was not involved in the study.

"The trial is interesting and related to relevant clinical and interdisciplinary questions," Dr Zips told Medscape Medical News.

"Finding ways to minimize the impact of any surgery is important, and particularly so in patients with cancer," said Jean Bourhis, MD, PhD, from the Institut Gustave Roussy in Villejuif, France, who is cochair of the ICHNO conference scientific committee.

"This research represents a significant step forward in reducing the complications caused by neck dissection in patients with head and neck tumors, Dr Bourhis said in a statement.

The report reconfirms that sentinel lymph node biopsy "is an effective minimally invasive procedure in oral cavity cancers," said Abraham Kuriakose, MD, professor and vice chair of the Department of Head and Neck/Plastic and Reconstructive Surgery, and director of Translational Research at the Roswell Park Cancer Institute in Buffalo, New York, who was not part of the study.

"In this respect, it is an important observation. However, it must be noted that in the presented study, unlike other sentinel lymph node trials, patients with early- and advanced-stage tumors were included. Therefore, the data from this study cannot readily be applied in early-stage T1, T2 oral cavity cancers," Dr Kuriakose told Medscape Medical News.

He believes that the accuracy of detection of sentinel lymph node using 99mTc-tilmanocept is "comparable" to that reported in other sentinel lymph node studies reported in American and European populations.

"The authors have not tested or demonstrated that the new radiotracer is any better than 99mTc-sulphur colloid, which was used in previous studies. In addition, the conclusions of the abstract do not reflect the data," Dr Kuriakose said.

"Since the study did not compare sentinel lymph node biopsy with elective neck dissection, it cannot claim that the technique will reduce the number of elective neck dissections. This clearly needs a randomized study comparing SLN biopsy and elective neck dissection."

This study was sponsored by Navidea Biopharmaceuticals. Dr de Bree reports being a consultant for Navidea. Dr Zips, Dr Bourhis, and Dr Kuriakose have disclosed no relevant financial relationships.

5th International Conference on Innovative Approaches in Head and Neck Oncology (ICHNO): Abstract OC-041. Presented February 13, 2015.

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