An article published in the Journal of Thoracic and Cardiovascular Surgery proposes the use of fluorescent-targeted molecular contrast agents to help identify adenocarcinoma, a type of lung cancer. In 50 adenocarcinoma patients aged 25–85, 46 of 50 lung adenocarcinomas (92%) were fluorescent. Tumors ranged in size from 0.3 cm to 7.5 cm (mean, 2.6 cm). No false uptake occurred, and, in two cases, intraoperative imaging revealed tumor metastases that had not previously been discovered. According to the researchers, the study was the first time near-infrared imaging had been used in thoracic surgery to identify pulmonary nodules that had not been diagnosed preoperatively.
Patients were each given the contrast agent through intravenous infusion 4 hours prior to surgery. In situ imaging only took 8 minutes to perform, substantially better than the localized options currently being used.
Four adenocarcinomas were not fluorescent, and immunohistochemistry showed that these adenocarcinomas did not express folate receptor alpha (FRalpha), a surface protein to which the molecular conjugate binds. Tumor fluorescence was also independent of nodule size, histology, and tumor differentiation. And molecular imaging identified only 7 of the 50 adenocarcinomas in situ in the patient without bisection. The most important factor influencing whether fluorescent tumors were detected in situ was the location of the tumor.
Sunil Singhal, MD, assistant professor of surgery, Penn Medicine, University of Pennsylvania Health System (Philadelphia, PA) wrote that he and the rest of the researchers are actively exploring other methods that would allow deeper penetration of fluorescent light. However, for now, the study serves as an excellent launching point for new ways to approach surgery and cancer care. —Sean McGuire
Okusanya OT, DeJesus EM, Jiang JX, et al. Intraoperative molecular imaging can identify lung adenocarcinomas during pulmonary resection. J Thorac Cardiovasc Surg. 2015;150(1):28-35.
