The complementary value of intraoperative fluorescence imaging and Raman spectroscopy for cancer surgery: combining the incompatibles.

A clear margin is an important prognostic factor for most solid tumours treated by surgery. Intraoperative fluorescence imaging using exogenous tumour-specific fluorescent agents has shown particular benefit in improving complete resection of tumour tissue. However, signal processing for fluorescence imaging is complex, and fluorescence signal intensity does not always perfectly correlate with tumour location. Raman spectroscopy has the capacity to accurately differentiate between malignant and healthy tissue based on their molecular composition. In Raman spectroscopy, specificity is uniquely high, but signal intensity is weak and Raman measurements are mainly performed in a point-wise manner on microscopic tissue volumes, making whole-field assessment temporally unfeasible. In this review, we describe the state-of-the-art of both optical techniques, paying special attention to the combined intraoperative application of fluorescence imaging and Raman spectroscopy in current clinical research. We demonstrate how these techniques are complementary and address the technical challenges that have traditionally led them to be considered mutually exclusive for clinical implementation. Finally, we present a novel strategy that exploits the optimal characteristics of both modalities to facilitate resection with clear surgical margins.

Discrimination between oral cancer and healthy tissue based on water content determined by Raman spectroscopy.

Tumor-positive resection margins are a major problem in oral cancer surgery. High-wavenumber Raman spectroscopy is a reliable technique to determine the water content of tissues, which may contribute to differentiate between tumor and healthy tissue. The aim of this study was to examine the use of Raman spectroscopy to differentiate tumor from surrounding healthy tissue in oral squamous cell carcinoma. From 14 patients undergoing tongue resection for squamous cell carcinoma, the water content was determined at 170 locations on freshly excised tongue specimens using the Raman bands of the OH-stretching vibrations (3350-3550 cm(-1)) and of the CH-stretching vibrations (2910-2965 cm(-1)). The results were correlated with histopathological assessment of hematoxylin and eosin stained thin tissue sections obtained from the Raman measurement locations. The water content values from squamous cell carcinoma measurements were significantly higher than from surrounding healthy tissue (p-value < 0.0001). Tumor tissue could be detected with a sensitivity of 99% and a specificity of 92% using a cutoff water content value of 69%. Because the Raman measurements are fast and can be carried out on freshly excised tissue without any tissue preparation, this finding signifies an important step toward the development of an intraoperative tool for tumor resection guidance with the aim of enabling oncological radical surgery and improvement of patient outcome.

An oral cancer screening program in Brazil: Analysis of seven years of outcome after its implementation in the suburban cities of São Paulo.

OBJECTIVE: To describe the implementation of an oral cancer screening program at the Barretos Cancer Hospital (BCH) and present the outcome based on data obtained from 2014 to 2020. MATERIALS AND METHODS: The residents of the Regional Health District of Barretos (DRS-V) were personally invited by community health agents or nurses, and among 13,973 people, 15,222 oral examinations were carried out over the years in 18 of its municipalities. Oral examinations were performed at the Mobile Dental Unit and at the Prevention Department of the BCH. Inclusion criteria were being 35 years of age or older, having a personal history of tobacco or alcohol consumption, or having a lesion in the oral cavity found by community health agent or self-reported, regardless of age or risk factors. RESULTS AND CONCLUSION: The main result of our study was the stages of oral cancer among screen detected cases were smaller compared to cases in the hospital registry, in the state and in Brazil. Oral cancer detection rate per 1,000 oral examinations was 10.7.The early stages of oral cancer found by screening in primary care facilities or using mobile units suggest that, when organized, screening may improve the prognosis of oral cancer.

Experimental study on needle insertion force to minimize tissue deformation in tongue tissue.

This study reports on the effects of insertion velocity, needle tip geometry and needle diameter on tissue deformation and maximum insertion force. Moreover, the effect of multiple insertions with the same needle on the maximum insertion force is reported. The tissue deformation and maximum insertion force strongly depend on the insertion velocity and the tip geometry. No correlation was found between the outer diameter and the maximum insertion force for small needles (30G - 32G). The endurance experiments showed no remarkable difference in the maximum insertion force during 100 insertions.