Will fluorescence technique help ovarian cancer patients?

For the first time, researchers have conducted ovarian cancer surgery with the help of a fluorescent imaging agent that causes certain types of cancer cells to glow.

The imaging agent, discovered by Phillip Low of Purdue University, allowed surgeons at Groningen University in the Netherlands to see (and subsequently remove) malignant ovarian cells that might otherwise have gone unnoticed. The researchers say their advance could, potentially, improve the prognosis of ovarian cancer patients.

This video contains graphic surgical imagery.

Results of the study appear September 18, 2011 in the journal Nature Medicine.

The study reports that fluorescence-guided surgeries were performed on ten women. These women were injected with a special fluorescence-containing liquid – a combination of fluorescein iso-thiocyanate and folate – before surgery. The liquid causes ovarian cancer cells to glow in the majority of patients. (In their paper, the researchers explain that this liquid fluorescence was accepted by the malignant cells because it contained folate; most malignant ovarian tumors tend to have lots of receptors for folate, otherwise known as Vitamin B9.)

Low said:

Ovarian cancer is notoriously difficult to see, and this technique allowed surgeons to spot a tumor 30 times smaller than the smallest they could detect using standard techniques. By dramatically improving the detection of the cancer – by literally lighting it up – cancer removal is dramatically improved.

The cancer cells glow only in the presence of a special light and are then displayed on a monitor beside the patient during surgery. This helps surgeons identify and remove extremely small patches of cancer-infected tissue (as small as 1/10 mm) which, with the naked eye or traditional imaging techniques like CAT scans or MRIs, would have been indistinguishable from healthy tissue. Co-author Vasilis Ntziachristos, of the Technical University of Munich in Germany, told Nature News online:

This advance represents a real paradigm shift in surgical imaging. Until now we could only rely on the human eye to find carcinogenic tissue, or non-specific dyes that would colour the vascular tissue as well as particular cancer cells. Now we are going after precise molecular signals and not simply physiology.

The team’s research is notable because ovarian cancer, especially if discovered in later stages, often has a poor prognosis. According to Nature News:

Of all the gynaecological cancers — ovarian, vaginal and uterine — ovarian is the greatest killer of women in both the United States and Europe.

Cutting out the maximum amount of cancerous tissue with fluorescence-guided surgery could give ovarian patients an increased chance of having post-op chemotherapy kill the remaining cancer — in theory, at least. The study’s authors acknowledge they are unsure of how their use of fluorescence to identify cancer cells will affect ovarian cancer patients’ long-term post-surgery success. That’s because this surgical technique is new and a study of life expectancy would necessitate following up with patients over a period of many years.

Bottom line: According to a study published September 18, 2011 in the journal Nature Medicine, surgeons at Groningen University in the Netherlands used fluorescent molecules to flag clusters of ovarian tumor cells that would have been undetectable with standard techniques. Phillip Low of Purdue University discovered the fluorescent imaging agent.

Read more at Nature News
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