The other day an interesting paper came to my attention entitled:
“Intraoperative tumor-specific fluorescence imaging in ovarian cancer by folate receptor-α targeting: first in-human results”
Thanks to my translational research friend Angela Alexander for highlighting it!
The idea behind this concept is that fluorescence technology can be used to help guide ovarian cancer surgery more effectively, since the tumours tend to be small and hard to see for surgeons performing the excision:
“Tumor-specific intraoperative fluorescence imaging may improve staging and debulking efforts in cytoreductive surgery and thereby improve prognosis.”
Folate receptor-α as a tool for imaging originally came from an understanding of the biology of the disease:
“The overexpression of folate receptor-α (FR-α) in 90–95% of epithelial ovarian cancers prompted the investigation of intraoperative tumor-specific fluorescence imaging in ovarian cancer surgery using an FR-α–targeted fluorescent agent.”
This marker (FR-α) be easily detected either on tumour cells in ascites fluid or on tumor tissue obtained during staging laparoscopy or primary surgery.
What did the results show?
“In this limited series, we showed that the use of intraoperative tumor-specific fluorescence imaging of the systemically administered FR-α–targeted agent folate-FITC offers specific and sensitive real-time identification of tumor tissue during surgery in patients with ovarian cancer and the presence of FR-α–positive tumors.”
It was also encouraging to see further validity is also provided by negative results:
“One patient presented with a malignant tumor that did not express FR-α, and consequently, no fluorescence was detected.”
What do these results mean?
I think van Dam et al., (2011) encapsulated the significance of the imaging test nicely:
“The use of targeted fluorescent agents could provide a paradigm shift in surgical imaging as it allows an engineered approach to improving tumor staging and the technique of cytoreductive surgery and thereby improving the outcome in ovarian cancer.”
There are potential applications too associated with clinical research too, since Morphotek/Eisai are investigating farletuzumab, a humanized IgG1 antibody that targets folate receptor alpha in ovarian and other cancers. Using this imaging technique could be used to determine the drugs effectiveness in reducing the tumour in patients in a non-invasive fashion.
Of course, the initial trials are being undertaken in the metastatic setting, but if successful, I could see a role for the agent developing in neoadjuvant disease to shrink the tumour margins prior to surgery. Having an appropriate marker test, coupled with a valid imaging technique could well lead to improvements in survival down the line.
Overall, folate receptor-α could well be an interesting new development to watch out for over the next couple of years as data from the imagining and drug trials mature.
van Dam, G., Themelis, G., Crane, L., Harlaar, N., Pleijhuis, R., Kelder, W., Sarantopoulos, A., de Jong, J., Arts, H., van der Zee, A., Bart, J., Low, P., & Ntziachristos, V. (2011). Intraoperative tumor-specific fluorescence imaging in ovarian cancer by folate receptor-α targeting: first in-human results Nature Medicine DOI: 10.1038/nm.2472