Background: Mohs micrographic surgery examines all margins of the resected sample and has a 99% cure rate. However, many nonmelanoma skin cancers (NMSCs) are not readily amenable to Mohs micrographic surgery. This defines an unmet clinical need to assess the completeness of non-Mohs micrographic surgery resections during surgery to prevent re-excision/recurrence.
Objective: We sought to examine the utility of quenched activity-based probe imaging to discriminate cancerous versus normal-appearing skin tissue.
Methods: The quenched activity-based probe GB119 was applied to NMSC excised from 68 patients. We validated activation of the probe for hematoxylin-eosin-confirmed cancerous tissue versus normal-appearing skin tissue.
Results: Topical application of the probe differentiated basal cell carcinoma and squamous cell carcinoma from normal-appearing skin with overall estimated sensitivity and specificity of 0.989 (95% confidence interval 0.940-1.00) and 0.894 (95% confidence interval 0.769-0.965), respectively. Probe activation accurately defined peripheral margins of NMSC as compared with conventional hematoxylin-eosin-based pathology.
Limitations: This study only examined NMSC debulking excision specimens. The sensitivity and specificity for this approach using final NMSC excision margins will be clinically important.
Conclusions: These findings merit further studies to determine whether quenched activity-based probe technology may enable cost-effective increased cure rates for patients with NMSC by reducing re-excision and recurrence rates with a rapid and easily interpretable technological advance.
Keywords: cathepsin-B; cathepsin-L; molecular optical imaging; nonmelanoma skin cancer; quenched activity-based probe; re-excision rate; topical application.
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