Trial results evaluating two photon fluorescence microscopy (TPFM) for assessing surgical margins in Basal Cell Carcinoma during Mohs surgery were posted on ClinicalTrials.gov on 2026-03-13. The study reported a mean specificity of 97.8% for TPFM in detecting residual carcinoma.
Background
Basal cell carcinoma (BCC) is the most common type of skin cancer. Mohs micrographic surgery is a highly effective treatment for BCC, particularly for tumors on cosmetically sensitive areas or those with aggressive features. A critical step in Mohs surgery involves the microscopic examination of excised tissue margins to ensure complete removal of cancer cells while preserving healthy tissue. This process traditionally relies on frozen section histology, which can be time-consuming and sometimes challenging due to tissue processing artifacts. The investigation of alternative, potentially faster or more precise, methods for intraoperative margin assessment, such as two photon fluorescence microscopy, aims to improve surgical efficiency and patient outcomes by reducing the risk of incomplete excisions.
Trial design
This completed study, with no specified phase, enrolled 135 participants with Basal Cell Carcinoma. The trial aimed to compare the diagnostic accuracy of two photon fluorescence microscopy (TPFM) for detecting residual basal cell carcinoma during Mohs surgery against the standard frozen section histology. The main question addressed was how similar the diagnosis of surgical margins using TPFM is compared to frozen section histology.
Key results
The trial results provided several key measurements regarding the agreement, specificity, and sensitivity of two photon fluorescence microscopy compared to frozen section histology:
- For the outcome titled "Agreement Between Frozen Sections and Two Photon Fluorescence Microscopy on Mohs Margins," two mean percentages were reported: 72.7% and 96.8%.
- Regarding "Specificity of Frozen Sections and Two-photon Fluorescence Microscopy Accounting for Errors Caused Frozen Section Artifacts," two mean percentages were reported: 97.8% and 91.1%. A two-proportion two-sided z-test, described as a superiority test comparing TPFM and frozen section specificity, yielded a p-value of 0.017.
- For "Sensitivity of Frozen Sections and Two-photon Fluorescence Microscopy on True Margin Diagnosis," two mean percentages were reported: 97.1% and 94.1%. A two-proportion, one-sided z-test yielded a p-value of 0.0047.
What this means
The posted results indicate that two photon fluorescence microscopy (TPFM) demonstrates high diagnostic accuracy for assessing basal cell carcinoma margins during Mohs surgery. With reported mean specificities of 97.8% and sensitivities of 97.1%, TPFM shows strong potential as a reliable tool. The statistically significant p-values (0.017 for specificity and 0.0047 for sensitivity) from comparisons with frozen section histology suggest that TPFM can match or potentially offer superior performance in certain diagnostic aspects. These findings imply that TPFM could serve as a valuable adjunct or alternative to traditional frozen section analysis, potentially leading to more efficient and precise intraoperative margin assessment for patients undergoing Mohs surgery for basal cell carcinoma.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for the study NCT05814900, titled "Investigation of Mohs Surgical Margins Using Two Photon Microscopy", were posted on 2026-03-13 on clinicaltrials.gov.