Two-color fluorescence-guided surgery treats head and neck cancer

13 Nov 2024

Oregon Health & Science University enhances visibility of both tumors and nerves for surgeons.

Successful surgery for head and neck squamous cell carcinoma (HNSCC) relies upon complete tumor removal and safe preservation of the fragile nerves in the vicinity. Both are challenging.

Fluorescence techniques are a potentially valuable way to image the relevant tissues for surgeons, but at present no clinically validated technology exists to enhance intraoperative cancer and nerve recognition.

A team of researchers from Oregon Health & Science University (OHSU) and Dartmouth College has now addressed this problem by developing a new imaging technique to enhance the visibility of both tumors and nerves during surgery.

As described in Journal of Biomedical Optics, the technique could be "a comprehensive fluorescence-guided surgery (FGS) tool for cancer resection and nerve sparing during HNSCC procedures for future clinical translation."

The project set out to develop a two-color approach, whereby different markers with different fluorescence behavior are targeted at the tumor cells and the nerve tissues.

"There are currently over 125 ongoing clinical trials for FGS contrast agents, but no clinical study has yet utilized dual-targeted contrast agents," noted the project in its published paper.

"However, preclinical studies have shown the potential power of two-color FGS strategies to visualize nerve and tumor tissues, where a visible nerve-specific probe and red-shifted tumor-targeted probe demonstrated the ability to specifically highlight both structures."

Maximized tumor removal with minimized damage

In trials on mice subjects, the project worked with a nerve-specific fluorophore named LGW05-75 and the tumor-targeted marker ABY-029. A custom-built small animal imaging system capable of real-time color and fluorescence imaging was used to spectrally separate the fluorescence signals using conventional bandpass imaging platforms.

As well as direct fluorescence from the different tissue types, this two-color imaging approach was used to successfully generate false-colored images where nerve tissue is depicted as green false color and tumor tissue is depicted as red false color. This means that a multi-color merged image for ready visualization of tumor tissues to be resected and nerve tissues to be avoided can be produced, to further aid surgeons.

When applied to a human HNSCC xenograft model, results confirmed that the two types of fluorophores could be used together to clearly differentiate between cancerous tissues and nerves. The nerve-specific fluorophore showed no significant interference from surrounding tumor tissues, ensuring accurate nerve visualization even in the presence of cancer.

"This advancement in FGS offers a promising tool for surgeons, potentially improving their ability to perform cancer resections while minimizing nerve damage," commented OHSU. "By integrating this technique into clinical practice, the researchers hope to enhance surgical outcomes and reduce the long-term complications associated with HNSCC surgeries."