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RCM, HD-OCT useful for evaluation of oral hedgehog inhibitor-induced BCC regression

The use of reflectance confocal microscopy and high-definition optical coherence tomography may be valuable tools for noninvasively visualizing oral hedgehog inhibitor-induced regression of basal cell carcinoma, according to researchers.

Researchers monitored six hedgehog inhibitor (HHI)-treated basal cell carcinomas (BCCs) in five patients using reflectance confocal microscopy (RCM) and high-definition optical coherence tomography (HD-OCT) in vivo. Examination was performed before and during treatment. The researchers then correlated any morphologic changes seen on imaging to changes in traditional histopathology.

The researchers found that the features characteristic of BCC seen on RCM and HD-OCT had decreased or disappeared completely after HHI treatment.

Although clinical evaluation rated three of the six tumors as having a complete response to treatment, imaging with RCM and HD-OCT revealed single and scattered tumors strands, which were correlated to residual tumor through histopathologic analysis, according to the researchers. The remaining three tumors were rated as having partial response on clinical exam, which was confirmed with noninvasive imaging and histopathological studies.

Overall, the use of RCM and HD-OCT allowed the researchers to uncover four distinct features indicating BCC regression after treatment with HHIs. These included the loss of the peripheral rim around the tumor nodules, loss of peripheral palisading tumor cells, blurry demarcation of residual nodules in contrast to the sharp tumor borders seen with untreated BCC, and an increase in fibrotic tissue.

Disclosures: Maier has received honoraria and consulting fees from AGFA HealthCare GmbH. Berking has received Honoria and consulting fees from Roche Pharma and Novartis Pharma.