Researchers have demonstrated a novel imaging technique known as dual probe difference specimen imaging, that could significantly improve the assessment of tumor margins during prostate cancer surgery.
- Uses spectrally distinct fluorophores paired with targeted and untargeted probes to rapidly and accurately assess prostate-specific membrane antigen status.
- This method overcomes limitations of current intraoperative tumor margin assessments that are laborious, lengthy, and disruptive to clinical workflow.
- The imaging technique offers the potential to reduce rates of reoperation or adjuvant therapies by improving the precision of initial prostatectomies.
- Future studies will further evaluate the utility of this technology for characterizing prostate margin status using prostate-specific membrane antigen as a biomarker.
What Is Dual Probe Difference Specimen Imaging?
Dual probe difference specimen imaging (DDSI) involves the use of paired antibody-based probes labeled with spectrally distinct fluorophores, one of which is targeted to prostate-specific membrane antigen (PSMA), a protein overexpressed in the majority of prostate cancer lesions. The probes are used to stain resected tissue specimens, and the resulting images provide a molecularly specific representation of tumor margins. A recent study published in the Journal of Biomedical Optics discusses how the method offers a simpler approach without the complexities of in vivo administration of fluorescent contrast agents.
Enhancing Contrast for Clearer Margins
A significant advantage of the DDSI approach is the substantial contrast difference it can display between PSMA-positive tumors and their respective normal tissues, i.e., prostate, adipose, and muscle. The contrast is even noticeable between high PSMA-expressing tumors and those with minimal PSMA expression. The DDSI method’s ratiometric correction for the nonspecific uptake patterns in resected tissues may be important in achieving this contrast, as it enhances the accuracy of prostate cancer margin assessment.
Validation of DDSI Protocol and Future Directions
The study’s DDSI protocol was validated on resected prostate cancers, providing a rapid and accurate assessment of PSMA status as a surrogate for prostate cancer margin status. The protocol’s clinical relevance offers potential for broader usage beyond breast cancer, where it was initially developed and optimized. PSMA was used as the prostate cancer-specific target due to its overexpression in more than 90% of primary prostate cancer lesions, tumor-positive lymph nodes, and metastases. The effectiveness of the DDSI protocol could facilitate rapid intraoperative cancer margin assessment in prostate cancer at the time of surgery, without the need to administer fluorescently labeled probes to the patient.
DDSI’s Potential Impact on Surgical Workflow
The DDSI protocol could significantly streamline the surgical workflow by reducing the reliance on frozen section analysis (FSA), a time-consuming process currently used for intraoperative tumor margin assessment. The DDSI protocol requires only 8 minutes in total, offering a less disruptive alternative to FSA, which can add an average of 20 minutes to surgical time in 90% of cases. The DDSI method also prevents tissue destruction, allowing for postoperative gold standard histopathology. The ability to make rapid intraoperative assessments could enable surgeons to make more informed decisions about removing additional tissues, potentially reducing the rate of reoperation or further adjuvant therapies, ultimately leading to improved patient outcomes.
The development and validation of the DDSI protocol offers a promising new approach to intraoperative tumor margin assessment in prostate cancer surgeries. The DDSI protocol’s ability to provide rapid, accurate, and biomarker-specific imaging could lead to a significant reduction in the need for reoperation or additional therapies, thereby improving patient outcomes. Further studies are needed to evaluate the protocol’s broader utility in other types of cancer.
Kwon, M. J., House, B. J., Barth, C. W., Solanki, A., Jones, J. A., Davis, S. C., & Gibbs, S. L. (2023). Dual probe difference specimen imaging for prostate cancer margin assessment. Journal of Biomedical Optics, 28(08). https://doi.org/10.1117/1.jbo.28.8.082806