Indocyanine Green Dye Saves Cancer Patients Lives


Indocyanine green dye (ICG) helps cancer patients survive. A team of researchers from the University of Pennsylvania discovered a new technique surgeons can use in removing cancerous tumors from cancer patients. This new approach increases the likelihood of patients having a positive outcome.

Indocyanine green dye works

Curing most cancer cases requires surgically removing a tumor. However, it is difficult to remove the entire tumor, which leads to cancer resurfacing in the patient. Professor of surgery at the University’s School of Veterinary Medicine and first author of this recent study, Dr. David Holt said, “Surgeons have had two things that tell where a cancer is during surgery: their eyes and their hands. This technique is offering surgeons another tool, to light tumors up during surgery.”

Dr. Holt joined forces with team leader and assistant professor of surgery, Dr. Sunil Singhal from University of Pennsylvania’s Perelman School of Medicine. Their manuscript is found in the PLOS ONE journal.

How it works is quite innovative. Surgeons inject Federal Drug Administration (FDA) approved indocyanine green dye that builds up around the cancerous tissue much more than a normal tissue. Then the surgeon shines an infrared light to make the cancer glow, which ultimately helps the surgeon see the cancerous area better, making it easier to take out the malignancy entirely.

Why indocyanine green dye is a better alternative

After undergoing surgery medical records show between 20 to 50 percent of patients with cancer experience a local reoccurrence of this dreaded disease. This indicates extraction of all the malignant tissue by surgeons was unsuccessful. In most cases, since surgeons typically cannot see the malignant tumor they have to use their fingers and feel around for differences to remove a diseased tissue.

The team of researchers searched for alternative ways to do this difficult surgery. They found a FDA approved contrasting agent called indocyanine green dye (ICG) that turns fluorescent when viewed using near-infrared imaging (NIR). Since blood vessels of tumors have, what are referred to as “leaky walls,” the ICG begins to accumulate or build up in the tumor tissue much more than in a normal tissue. The tumor “lights up” clear enough for surgeons to distinguish cancerous tissue when doing their surgery.

Results of the clinical trial

Five patients participated in the pilot study at the Hospital of the University of Pennsylvania. Initially, the patients had chest and lung cancer. Prior to surgery, each patient was injected with indocyanine green dye. Surgeons inspected the tumors using NIR imaging and removed the tumors. Surgeons were able to see, feel, and distinguish between non-tumors and tumors in four of the patients. However, NIR imaging for the fifth patient glowed in what was considered healthy areas in the lung, though the PET and CT scan signified a tumor as a solitary mass.

According to Dr. Holt, “It turns out he had diffuse microscopic cancer in multiple areas of the lung. We might have otherwise called this Stage I, local disease, and the cancer would have progressed. But because of the imaging and subsequent biopsy, he underwent chemotherapy and survived.”

Indocyanine green dye and NIR imaging is a great benefit to surgeons and patients alike; however, one of the disadvantages of ICG is that inflamed tissue surrounding tumors also absorbs the dye which makes it difficult, and at times, impossible to tell apart. Nonetheless, researchers at the university are searching for other options for targeted contrast agents to pinpoint and specify the cancerous tumor marker.

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George Zapo, CPH
George Zapo, CPH is certified in Public Health Promotion & Education. George focuses on writing informative articles promoting healthy behavior and lifestyles. Read more of George's articles at his website: