Intraoperative optical assessment of photodynamic therapy response of superficial oral squamous cell carcinoma

Abstract

This study investigated whether diffuse optical spectroscopy (DOS) measurements could assess clinical response to photodynamic therapy (PDT) in patients with head and neck squamous cell carcinoma (HNSCC). In addition, the correlation between parameters measured with DOS and the crosslinking of signal transducer and activator of transcription 3 (STAT3), a molecular marker for PDT-induced photoreaction, was investigated. Thirteen patients with early stage HNSCC received the photosensitizer 2-[1-hexyloxyethyl]-2-devinylpyropheophorbide-a (HPPH) and DOS measurements were performed before and after PDT in the operating room (OR). In addition, biopsies were acquired after PDT to assess the STAT3 crosslinking. Parameters measured with DOS, including blood volume fraction, blood oxygen saturation (StO 2), HPPH concentration (cHPPH), HPPH fluorescence, and blood flow index (BFI), were compared to the pathologic response and the STAT3 crosslinking. The best individual predictor of pathological response was a change in cHPPH (sensitivity ¼ 60%, specificity ¼ 100%), while discrimination analysis using a two-parameter classifier (change in cHPPH and change in StO 2) classified pathological response with 100% sensitivity and 100% specificity. BFI showed the best correlation with the crosslinking of STAT3. These results indicate that DOS-derived parameters can assess the clinical response in the OR, allowing for earlier reintervention if needed.

Optical imaging of tissue obtained by transbronchial biopsies of peripheral lung lesions

“…Optical spectroscopy can provide vascular and biochemical contrasts, which can produce enhanced sensitivity and specificity for tissue characterization. This was demonstrated in prior studies in oral, oropharyngeal, and lung cancers (3)(4)(5)(6)(7)(8)(9)(10)(11)(12). The primary objective of this study is to assess the feasibility and ability of a custom-built bimodal optical spectroscopy system combining diffuse reflectance spectroscopy (DRS) and diffuse fluorescence Original Article of Interventional Pulmonology Corner Optical imaging of tissue obtained by transbronchial biopsies of peripheral lung lesions spectroscopy (DFS) to enhance the on-site discrimination between malignant and benign specimens that are obtained by transbronchial biopsies of peripheral lung lesions.…”

“…This is advantageous as it offers the rapid on-site evaluation of the specimens obtained and immediate perspective regarding the direction of the diagnosis. Optical spectroscopy has been shown to be effective in characterizing cancer tissue in oral cavity and lung (3)(4)(5)7,8,10,11). In a recent study by Spliethoff et al, the lung tissues obtained from lobectomy or segmental lung resections from 13 patients were imaged using optical spectroscopy.…”

Assessing daylight & low-dose rate photodynamic therapy efficacy, using biomarkers of photophysical, biochemical and biological damage metrics in situ

“…Previous studies have shown that the formation of STAT3 cross-linking is dependent on the amount of photosensitizer, delivered light dose, and, light fluence rate [25,26,35]. In a study performed by Rohrbach et al [35], low light fluence rate HPPH-PDT induced higher STAT3 cross-linking in a head and neck tumor model.…”

“…Previous studies have shown that the formation of STAT3 cross-linking is dependent on the amount of photosensitizer, delivered light dose, and, light fluence rate [25,26,35]. In a study performed by Rohrbach et al [35], low light fluence rate HPPH-PDT induced higher STAT3 cross-linking in a head and neck tumor model. The authors correlated their results with the vascular shutdown caused in the beginning of the treatment with high light fluence rate, limiting the oxygen available to promote the photoreaction [35,36].…”

“…In a study performed by Rohrbach et al [35], low light fluence rate HPPH-PDT induced higher STAT3 cross-linking in a head and neck tumor model. The authors correlated their results with the vascular shutdown caused in the beginning of the treatment with high light fluence rate, limiting the oxygen available to promote the photoreaction [35,36]. …”