Ovarian tumors can’t hide from surgeons guided by new optical-imaging agent

Surgeons have used a new tumor-specific, near-infrared (NIR) fluorescent agent, combined with a dedicated camera-based imaging system, to find and resect ovarian tumors that are invisible to the naked eye and undetectable by the surgeon’s fingertips.

Alexander Vahrmeijer, MD, PhD, head of image-guided surgery at Leiden University Medical Center in the Netherlands, and colleagues tested the new agent, called OTL38, in 12 patients with ovarian cancer.

Developed at Purdue University, OTL38 is a conjugate of NIR fluorescent dye and a folate analog that binds to folate receptor-alpha (FRα), according to a news release from the American Association for Cancer Research.

In addition to measuring tolerability and pharmacokinetics, the team studied whether OTL38-guided surgery resulted in the detection of more tumors that were neither visible nor palpable during surgery.

As hoped, the OTL38 accumulated in FRα-positive tumors and metastases, enabling the surgeons to remove an additional 29 percent of malignant lesions that could not be identified with naked eyes and/or palpation.

Vahrmeijer says in the news release that a key fluorescent signal was detected in tumors in real time during a surgical procedure for ovarian cancer called cytoreduction.

“This allowed resection of additional tumor lesions that were not visible to the surgeons’ naked eyes,” Vahrmeijer reiterates. “Although more research is needed, this is hopefully the first step toward improving the surgical outcome of cancer patients.”

The Vahrmeijer study posted June 15 in Clinical Cancer Research.

For additional background on near-infrared optical imaging, click here.