Optical biopsy of epithelial cancers by optical coherence tomography

Optical coherence tomography (OCT) is an optical technique that measures the backscattering of near-infrared light by tissue. OCT yields in 2D and 3D images at micrometer-scale resolution, thus providing optical biopsies, approaching the resolution of histopathological imaging. The technique has shown to allow in vivo differentiation between benign and malignant epithelial tissue, through qualitative assessment of OCT images, as well as by quantitative evaluation, e.g., functional OCT. This study aims to summarize the principles of OCT and to discuss the current literature on the diagnostic value of OCT in the diagnosis of epithelial (pre)malignant lesions. The authors did a systematic search of the electronic databases PubMed and Embase on OCT in the diagnostic process of (pre)malignant epithelial lesions. OCT is able to differentiate between benign and (pre)malignant lesions of epithelial origin in a wide variety of tissues. In this way, OCT can detect skin cancers, oral, laryngeal, and esophageal cancer as well as genital and bladder cancer. OCT is an innovative technique which enables an optical biopsy of epithelial lesions. The incorporation of OCT in specific tools, like handheld and catheter-based probes, will further improve the implementation of this technology in daily clinical practice

PCN77 – Cost-effectiveness of cognitive-behavioral therapy and physical exercise for alleviating treatment-induced menopausal symptoms in breast cancer patients

Objectives Many breast cancer patients suffer from (severe) menopausal symptoms after an early onset of menopause caused by cancer treatment. The standard treatment for these complaints is hormone replacement therapy, which, however, is contraindicated for this group, as it may have tumor-promoting effects. The aim of this study was to assess the cost-effectiveness of three interventions aimed at alleviating these symptoms: cognitive-behavioral therapy (CBT), physical exercise (PE), and the combination of both (CBT+PE). Methods A cost-effectiveness analysis was performed from a health care system perspective. The primary outcome was incremental health care costs (IHCC) per patient with a clinically relevant improvement after six months of treatments. The secondary outcome was incremental costs per quality-adjusted life years (QALYs) gained over a five-year time period. This was assessed using a Markov model, populated with data from a recent randomized controlled trial evaluating the effectiveness of CBT, PE, and CBT+PE in the clinical setting and additional cost data. The robustness of the results was analyzed through one-way and probabilistic sensitivity analyses. Results IHCCs for alleviating one patient of the perceived symptom burden by a clinically relevant difference after six months of treatment were EUR€605 for CBT, EUR€1,847 for CBT+PT, and EUR€1,250 for PE alone, compared to the waiting list control group. CBT generated 0.009 additional QALYs at an additional cost of EUR€162, compared to the control group, leading to an Incremental Cost Utility Ratio (ICUR) of EUR€18,655 per QALY gained and The ICUR of CBT+PE was EUR€42,375 per QALY in comparison to the control group. CBT had a high probability (circa 61%) of being cost-effective at prevailing ceiling ratios. Conclusions CBT is likely the most cost-effective of the three interventions investigated for alleviating treatment-induced menopausal symptoms in breast cancer patient

The role of loudness perception in hearing aid fitting: Temporal, spectral and binaural effects

One of the main aims in individual hearing aid fitting is to restore loudness perception with hearing aids close to normal based on hearing aid prescription rules. In current hearing aid prescription rules loudness normalization is based on historic loudness data or on loudness models. Three limitations of this approach are addressed in this thesis. The first limitation is that the loudness data which form the basis of the prescription rules have been collected with static stimuli. However, as shown in this thesis, the loudness of dynamic stimuli is not well predicted by these models. The second limitation is that hearing aid prescription rules are threshold based. But in this thesis is shown that, thresholds are a very poor predictor of the loudness function, and individual differences are large. Finally, hearing aid prescription rules assume that spectral and binaural loudness summation are reduced by hearing loss, and are not significantly affected by loudness normalization. In hearing-impaired listeners with different degrees of symmetrical hearing losses the effect of loudness normalization was studied. It was shown that for larger hearing losses spectral and binaural loudness summation usually is much larger than for normal hearing listeners, especially for broadband signals. It was also shown that without loudness normalization in bilaterally presented signals the lower frequency part of the signal had a larger contribution to the overall loudness perception than the higher frequency part. To optimize hearing aid fitting, individual loudness measurements are recommended, including loudness measurements of broadband signals

The role of loudness perception in hearing aid fitting: Temporal, spectral and binaural effects

One of the main aims in individual hearing aid fitting is to restore loudness perception with hearing aids close to normal based on hearing aid prescription rules. In current hearing aid prescription rules loudness normalization is based on historic loudness data or on loudness models. Three limitations of this approach are addressed in this thesis. The first limitation is that the loudness data which form the basis of the prescription rules have been collected with static stimuli. However, as shown in this thesis, the loudness of dynamic stimuli is not well predicted by these models. The second limitation is that hearing aid prescription rules are threshold based. But in this thesis is shown that, thresholds are a very poor predictor of the loudness function, and individual differences are large. Finally, hearing aid prescription rules assume that spectral and binaural loudness summation are reduced by hearing loss, and are not significantly affected by loudness normalization. In hearing-impaired listeners with different degrees of symmetrical hearing losses the effect of loudness normalization was studied. It was shown that for larger hearing losses spectral and binaural loudness summation usually is much larger than for normal hearing listeners, especially for broadband signals. It was also shown that without loudness normalization in bilaterally presented signals the lower frequency part of the signal had a larger contribution to the overall loudness perception than the higher frequency part. To optimize hearing aid fitting, individual loudness measurements are recommended, including loudness measurements of broadband signals

Learning curve and interobserver variance in quantification of the optical coherence tomography attenuation coefficient

The learning curve and interobserver variance of attenuation coefficient (μOCT ) determination from optical coherence tomography (OCT) images were quantified. The μOCT of normal and diseased vulvar tissues was determined at five time points by three novice students and three OCT experts who reached consensus for reference. Students received feedback between time points. Eventually, variance in μOCT was smaller in images of diseased tissue than in images of normal vulvar tissue. The difference between the consensus and student μOCT values was larger for smaller values of μOCT . We conclude that routine μOCT determination for tissue classification does not require extensive trainin

Optical Coherence Tomography in vulvar intraepithelial neoplasia

Abstract. Vulvar squamous cell carcinoma (VSCC) is a gynecological cancer with an incidence of two to three per 100,000 women. VSCC arises from vulvar intraepithelial neoplasia (VIN), which is diagnosed through painful punch biopsy. In this study, optical coherence tomography (OCT) is used to differentiate between normal and VIN tissue. We hypothesize that (a) epidermal layer thickness measured in OCT images is different in normal tissue and VIN, and (b) quantitative analysis of the attenuation coefficient (μ oct ) extracted from OCT data differentiates VIN from normal vulvar tissue. Twenty lesions from 16 patients are imaged with OCT. Directly after data acquisition, a biopsy is performed. Epidermal thickness is measured and values of μ oct are extracted from 200 OCT scans of normal and VIN tissue. For both methods, statistical analysis is performed using Paired Mann–Whitney-test. Correlation between the two methods is tested using a Spearman-correlation test. Both epidermal layer thickness as well as the μ oct are different between normal vulvar tissue and VIN lesions (p<0.0001 ). Moreover, no correlation is found between the epidermal layer thickness and μ oct . This study demonstrates that both the epidermal thickness and the attenuation coefficient of vulvar epithelial tissue containing VIN are different from that of normal vulvar tissue