New Fluorescence Agent Could Aid in Removal of Undetected Ovarian Tumors

Surgeons were able to remove 29% of additional tumors using OTL38.

Researchers have created a novel imagining technique that could potentially detect ovarian tumors that are invisible to the eye.

The imagining technique involves a new tumor-specific fluorescent agent called OTL38, which binds to folate receptor-alpha (FRα). FRα is expressed in more than 90% of ovarian cancers, according to a study published by Clinical Cancer Research.

"Surgery is the most important treatment for ovarian cancer, and surgeons mainly have to rely on their naked eyes to identify tumor tissue, which is not optimal,” said researcher Alexander L. Vahrmeijer MD, PhD. “Near infrared (NIR) fluorescence imaging is a novel technique that may assist the surgeons to improve visualization of tumors during surgery.”

Researchers first conducted a clinical trial in 30 healthy patients to determine the tolerability and pharmacokinetics of OTL38, letting researchers determine dosages and optimal timing windows. They then conducted a clinical trial in 12 patients with ovarian cancer to discover whether or not the fluorescence helped discover additional tumors.

It was discovered that OTL38 collected in tumors expressing FRα, and surgeons were able to remove an additional 29% of malignant tumors, the study noted.

"A limitation of this study is that we cannot say yet what the impact of our findings is on cure or survival of the patients,” said Dr Vahrmeijer. “It is reasonably plausible to assume that if more cancer is removed the survival will be better. However, long-term follow-up studies need to be performed in large patient groups to prove such effects.”

Researchers said that larger studies to explore the sensitivity and specificity of the technique are being planned.

"In our study, using a tumor-specific fluorescent agent and a dedicated imaging system, a 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," concluded Dr Vahrmeijer. "Although more research is needed, this is hopefully the first step toward improving the surgical outcome of cancer patients."