Assessment of regional lymph node status in breast cancer is of important staging and prognostic value. Even though formal histological examination is the currently accepted standard of care, optical imaging techniques have shown promising results in disease diagnosis. In the present article, we review six spectroscopic techniques and focus on their use as alternative tools for breast cancer lymph node assessment. Elastic scattering spectroscopy (ESS) seems to offer a simple, cost-effective, and reproducible method for intraoperative diagnosis of breast cancer lymph node metastasis. Optical coherence tomography (OCT) provides high-resolution tissue scanning, along with a short data acquisition time. However, it is relatively costly and experimentally complex. Raman spectroscopy proves to be a highly accurate method for the identification of malignant axillary lymph nodes, and it has been further validated in the setting of head and neck cancers. Still, it remains time-consuming. Near-infrared fluorescence imaging (NIRF) and diffuse reflectance spectroscopy (DFS) are related to significant advantages, such as deep tissue penetration and efficiency. Fourier-transform infrared spectroscopy (FTIR) is a promising method but has significant drawbacks. Nonetheless, only anecdotal reports exist on their clinical use for cancerous lymph node detection. Our results indicate that optical imaging methods can create informative and rapid tools to effectively guide surgical decision-making.

Oral malignant and potentially malignant conditions affect several people worldwide each year. The early diagnoses of these conditions play an important role in prevention and recovery. Vibrational spectroscopy techniques such as Raman spectroscopy (RS) and Fourier-transform infrared (FTIR) spectroscopy are used in the early, non-invasive, label-free diagnosis of malignant and pre-malignant conditions, and are areas of active research. However, there is no conclusive evidence suggesting the translatability of these methods into clinical practice. This systematic review and meta-analysis presents pooled evidence for RS and FTIR methods in the detection of malignant and potentially malignant conditions of the oral cavity. Electronic databases were searched for published literature on RS and FTIR in the diagnosis of oral malignant and potentially malignant conditions. The pooled sensitivity, specificity, diagnostic accuracy, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), pre-test, and post-test probability were then calculated using the random-effects model. A subgroup analysis was conducted separately for RS and FTIR methods. A total of 12 studies were included (8 of RS; 4 of FTIR) as per the eligibility criteria. The pooled sensitivity and specificity of the vibrational spectroscopy methods were calculated to be 0.99 (95% confidence interval [CI]: 0.90, 1.00) and 0.94 (95% CI: 0.85, 0.98), respectively. The area under the curve (AUC) for the summary receiving operator characteristic curve was found to be 0.99 (0.98-1.00). Therefore, the results obtained in this study suggest that the RS and FTIR methods offer great potential to be used in the early diagnosis of oral malignant and pre-malignant conditions.

The conventional radiotherapy protocol to treat head-and-neck cancer is usually followed by tooth-decay onset. Radiation impact on mineralized tooth structures is not well-understood. This systematic review aimed to collect the recorded effects of therapeutic radiation on tooth chemical, structural and mechanical properties, in relation with their means of investigation.
Systematic search (January 01 2012 - September 30 2021) terms were \"Radiotherapy\", \"Radiation effects\", \"Dental enamel\", \"Dentin\", \"Human\" and \"Radiotherapy\" NOT \"Laser\".
PubMed, DOSS and Embase databases were searched.
Selected studies compared dental enamel, coronal and root dentin properties before and after in vitro or in vivo irradiation up to 80 Gy.
The systematic search identified 353 different articles, with 28 satisfying inclusion criteria. Their reference lists provided two more. Twenty-two studies evaluated dental enamel evolution, nine assessed coronal dentin and eight concerned root dentin. Coronal and root dentin results indicate a major impact of the radiation on their organic matrix. Dental enamel\'s chemical properties are less modified. Enamel and root dentin\'s hardness are decreased by therapeutic radiation, but no consensus arises for coronal dentin.
Our findings revealed some interesting information about enzymatic degradation mechanisms of dentin organic matrix and highlighted that dental hard-tissue characterization requires highly specific expertise in materials science. That scientific knowledge is necessary to design suitable protocols, adequately analyze the obtained data, and, thus, provide relevant conclusions.
Better knowledge and understanding of the mechanisms involved in the degradation of enamel and dentin would enable development of new preventive and therapeutic methods for improved medical care of patients undergoing radiotherapy.

Thyroid cancer\'s incidence has increased in the last decades, and its diagnosis can be a challenge. Further and complementary testing based in biochemical alterations may be important to correctly identify thyroid cancer and prevent unnecessary surgery. Fourier-transform infrared (FTIR) spectroscopy is a metabolomic technique that has already shown promising results in cancer metabolome analysis of neoplastic thyroid tissue, in the identification and classification of prostate tumor tissues and of breast carcinoma, among others. This work aims to gather and discuss published information on the ability of FTIR spectroscopy to be used in metabolomic studies of the thyroid, including discriminating between benign and malignant thyroid samples and grading and classifying different types of thyroid tumors.