Cerenkov Luminescence Imaging and Flexible Autoradiography for specimen margin assessment during breast-conserving cancer surgery

Abstract

Background Among women with breast cancer who undergo breast-conserving surgery (BCS), 20-25% require further surgery due to close or involved margins. Improved techniques are needed to assess resection margins.

Purpose The study aims were to assess the feasibility of the combined techniques of Cerenkov Luminescence Imaging—Flexible AutoRadiography (CLI-FAR) to assess excision specimen margins in women undergoing breast-conserving surgery (BCS) and to determine the diagnostic performance of intraoperative CLI-FAR imaging with postoperative histopathology as the reference standard.

Materials and Methods Women undergoing BCS were recruited prospectively at a single centre over thirteen months. Patients were injected with 250MBq +/- 10MBq of 18F-fluorodeoxyglucose (18F-FDG), 145 minutes before surgery and the excised specimens were imaged intraoperatively. The surgically excised tumour was initially imaged using conventional x-ray, and margins suspected to be involved by tumor were then imaged using CLI-FAR. CLI-FAR imaging was performed using the LightPath system® (Lightpoint®), an in vitro diagnostic device designed to identify and locate positron-emitting radionuclides. Any suspicious margin underwent an immediate re-excision in the form of cavity shavings. Sensitivity, specificity, positive and negative predictive value whilst considering histopathological assessment as the golden standard were used to assess the performance of CLI-FAR.

Results In all, 54 specimens were imaged in 52 patients with a total of 104 margins reviewed using CLI-FAR. The results showed a specificity of 97.8% (89/91, 95% CI: 95.0%, 100.6%), sensitivity of 76.9% (10/13, 95% CI: 68.3%, 85.0%), positive predictive value (PPV) of 83.3% (10/12, 95% CI: 76.2%, 90.5%) and negative predictive value (NPV) of 96.7% (89/92, 95% CI: 93.3%, 100.2%). In all, 8 patients had 10 positive margins on CLI-FAR imaging and were treated accordingly. CLI-FAR imaging reduced the re-excision rate by (17.3/25) 69%.

Conclusion CLI-FAR imaging is a promising technique for intraoperative margin assessment in women undergoing BCS for invasive breast cancer.