Laryngeal cancer, primarily squamous cell carcinoma, represents a significant health burden, necessitating precise diagnostic and therapeutic strategies to optimize patient outcomes. Endoscopic evaluation has become a cornerstone in the management of laryngeal cancer, aiding in accurate tumor visualization, localization, and staging. Recent advances in laser technology and photobiomodulation (PBM) have introduced new avenues for enhancing the precision and efficacy of these evaluations. This review aims to provide a comprehensive overview of the current techniques in preoperative and operative endoscopic evaluation, discuss their limitations, and explore future directions for enhancing the effectiveness of these evaluations, with a particular focus on the potential of laser and PBM technologies.
Preoperative endoscopic evaluation typically involves both flexible and rigid laryngoscopy. Flexible laryngoscopy allows for a comprehensive examination of the larynx, including assessment of vocal cord mobility and detection of synchronous lesions. Rigid laryngoscopy, on the other hand, provides superior visualization of the laryngeal structures, facilitating precise localization and staging of the tumor.
The integration of these techniques has significantly improved the accuracy of laryngeal cancer staging. Studies have demonstrated that endoscopic evaluations can detect submucosal spread and minor cartilage involvement that might be missed by conventional imaging modalities such as computed tomography or magnetic resonance imaging [1]. Furthermore, endoscopic evaluations can identify synchronous lesions, which occur in up to 10% of patients with laryngeal cancer [2].
Laser technology has emerged as a valuable tool in the preoperative evaluation and treatment of laryngeal cancer. Laser-assisted endoscopy allows for precise ablation of suspicious lesions and can be used to obtain high-quality biopsy specimens. Additionally, laser imaging techniques, such as laser fluorescence, can enhance the detection of malignant tissues by highlighting areas of abnormal metabolic activity [3]. These laser-based methods provide a higher degree of accuracy in identifying cancerous tissues, thus improving the staging process and informing surgical planning.
Intraoperative endoscopic evaluation is crucial for guiding surgical resection and ensuring clear margins. White light endoscopy was a standard evaluation procedure (Fig. 1). Advanced imaging techniques such as narrow-band imaging (NBI) and high-definition video endoscopy have revolutionized intraoperative assessments. NBI enhances the visualization of vascular patterns, which can help differentiate between malignant and benign tissues [4]. High-definition video endoscopy provides detailed real-time images, allowing surgeons to achieve more precise resections (Fig. 2).
Figure 1. White light endoscopy.
Figure 2. (A) High-definition video endoscopy, (B) white light endoscopy.
These techniques have led to improved surgical outcomes, including higher rates of complete tumor resection and lower recurrence rates. A study by Smith et al. [5] found that the use of NBI during surgery resulted in a 15% increase in the detection of residual tumor tissue compared to standard white light endoscopy.
In addition to imaging, lasers play a significant role in the surgical treatment of laryngeal cancer. Laser surgery allows for precise removal of cancerous tissues with minimal damage to surrounding structures, reducing postoperative complications and preserving laryngeal function. CO2 lasers are particularly effective for excising early-stage tumors and managing recurrent lesions [6]. The precision of laser surgery makes it an ideal complement to endoscopic evaluation, enabling surgeons to target tumor margins accurately and minimize residual disease.
PBM, also known as low-level laser therapy, is a technique that uses low-intensity light to modulate biological processes. In the context of laryngeal cancer, PBM has shown promise in reducing postoperative pain, accelerating wound healing, and potentially enhancing immune responses against residual tumor cells [7].
PBM works by stimulating cellular processes through the absorption of light by chromophores within the cells. This leads to increased production of ATP, modulation of reactive oxygen species, and the release of growth factors that promote tissue repair and reduce inflammation [8]. In laryngeal cancer patients, PBM can be applied postoperatively to the surgical site to facilitate healing and reduce the risk of infection.
Several clinical studies have reported positive outcomes with PBM in head and neck cancer patients. For instance, PBM has been used to manage radiation-induced mucositis, a common side effect in patients undergoing radiotherapy for laryngeal cancer [9]. PBM treatment has resulted in reduced severity and duration of mucositis, improving patients’ quality of life during treatment. Moreover, PBM may enhance the effects of traditional therapies by improving the microenvironment around the tumor, making it less conducive to cancer growth [10].
Despite the advancements in endoscopic technology, including the integration of lasers and PBM, several limitations remain. One significant challenge is the accurate detection of tumor margins. While NBI and other imaging modalities have improved margin visualization, there is still a risk of residual tumor tissue being left behind, particularly in cases of submucosal spread [11].
Another limitation is the differentiation between malignant and benign lesions. While NBI enhances vascular pattern visualization, it is not always definitive, and false positives can occur, leading to unnecessary biopsies or wider resections [12]. Additionally, rigid laryngoscopy, though effective, can be uncomfortable for patients and requires general anesthesia, which may not be suitable for all patients.
The use of laser technology, while advantageous, also comes with challenges. For instance, the precision required in laser surgery demands a high level of expertise, and there is a learning curve associated with mastering these techniques. Moreover, the costs associated with laser equipment can be prohibitive, limiting access in some healthcare settings [13].
Emerging technologies hold promise for addressing these limitations and further enhancing the effectiveness of endoscopic evaluations in laryngeal cancer. Techniques such as confocal laser endomicroscopy and optical coherence tomography (OCT) are being explored for their potential to provide even more detailed and accurate assessments of laryngeal tissues [14].
Confocal laser endomicroscopy offers real-time microscopic imaging of tissues, which could improve the differentiation of malignant and benign lesions. OCT provides high-resolution cross-sectional images of tissues, allowing for more precise detection of tumor margins and submucosal spread [15].
Additionally, advancements in artificial intelligence (AI) and machine learning are being integrated into endoscopic evaluations. AI algorithms can assist in the real-time analysis of endoscopic images, potentially improving diagnostic accuracy and reducing the risk of human error [16].
Endoscopic evaluation remains a critical component in the management of laryngeal cancer, significantly enhancing the accuracy of preoperative assessment and the precision of surgical interventions. The integration of laser technology and PBM into endoscopic practice has further advanced the field, offering new tools for diagnosis, treatment, and postoperative care. Despite these advancements, challenges such as accurate margin detection and differentiation of malignant lesions persist. Future innovations, including advanced imaging techniques, AI integration, and continued developments in laser and PBM technologies, hold the potential to overcome these limitations and further improve patient outcomes. Continuous research and development in this field are essential to realize the full potential of endoscopic evaluations in laryngeal cancer management.
None.
The patient whose image is included in this study has provided informed consent for the use of their photograph for research and publication purposes. The consent was obtained after the patient was fully informed about the purpose of the study, the potential risks, and how the image would be used, including any dissemination in scientific journals, presentations, or other media. The patient understood that their identity would be kept confidential and that participation was voluntary. The patient was also informed of the right to withdraw consent at any time without any impact on their care.
All work was done by SHW.
No potential conflict of interest relevant to this article was reported.
This research was supported and funded by SNUH Lee Kun-hee Child Cancer & Rare Disease Project, Republic of Korea (grant number: 23C-023-0100).
None.
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Author ORCID Information Seung Hoon Woo
Funding Information Seoul National University Hospital |
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