Pathologic effects of external-beam irradiation on human vocal folds

Late laryngeal dysfunction in head and neck cancer survivors

Objectives

Head and neck cancer (HNC) survivorship issues are areas of increasing research interest. Laryngeal dysfunction in HNC patients is particularly important given the importance of the larynx in voice, swallowing, and airway protection. The objective of our study is to characterize late laryngeal dysfunction in a cohort of long-term HNC survivors.

Methods

HNC survivors who were at least 2 years post-treatment were recruited prospectively for standard collection of videolaryngoscopy findings, videofluoroscopic swallowing studies, and assessment of clinical outcomes. Descriptive statistics were performed and clinical presentation and outcomes were compared between survivors >10 years and <10 years post-treatment. Additional factor analysis to correlate clinical outcomes with clinical variables was performed.

Results

Thirty participants were analyzed with a mean age of 66 years. The majority were male (80%) patients treated for oropharyngeal squamous cell carcinoma (67%). Within the cohort, 43% underwent primary chemoradiation therapy and had 13% radiation alone. Common presenting symptoms included swallowing dysfunction (83%), voice change (67%), and chronic cough (17%). Laryngeal findings on video laryngoscopy include vocal fold motion abnormalities (VFMA) in over half of participants (61%) and mucosal changes in 20%. A weak correlation was found between time since treatment and laryngeal dysfunction (r = .182, p = .34), and no correlation was found between age, sex, time since treatment, or primary site and the presence or absence of VFMA, G-tube status, or tracheostomy-tube status.

Conclusion

Late laryngeal dysfunction in HNC survivors contributes to significant morbidity, is difficult to treat, and remains static decades after treatment for their original cancer.

Lay Summary

The voice-box, or the larynx, plays an important role in voice, swallowing and airway protection. It is particularly vulnerable to radiation-related damage and changes. This study demonstrates the sequelae of long-term damage of the larynx in head and cancer survivors.

Level of Evidence

IV.

The Histological Background of Recurrence in Laryngeal Squamous Cell Carcinoma: An Insight into the Modifications of Tumor Microenvironment

Recurrent laryngeal carcinoma presents differences from the primary tumor that largely depend on the treatment. In this article, we review the histologic and molecular treatment-induced changes that may affect the diagnosis of recurrent laryngeal carcinoma, the assessment of predictive markers, and the response to treatment with immune checkpoint inhibitors. Radiotherapy induces profound modifications that are strictly related to necrosis of different tissue components, fibrosis, and damage of the tumor vessels. Postradiotherapy recurrent/persistent laryngeal squamous cell carcinoma typically presents a discohesive growth pattern within a fibrotic background associated with significant changes of the tumor immune microenvironment, with both important immunosuppressive and immunostimulatory effects. Overall, the increase of immunoregulatory cells and immune checkpoints such as CTLA-4, TIM-3, PD-1, and PD-L1 induced by radiotherapy and chemotherapy strongly supports the use of immune checkpoint inhibitors in recurrent/persistent laryngeal carcinoma. Future studies aiming to identify predictive factors of the response to immune checkpoint inhibitors should consider such treatment-induced modifications.

Radiation-induced neuropathies in head and neck cancer: prevention and treatment modalities

Head and neck cancer (HNC) is the sixth most common human malignancy with a global incidence of 650,000 cases per year. Radiotherapy (RT) is commonly used as an effective therapy to treat tumours as a definitive or adjuvant treatment. Despite the substantial advances in RT contouring and dosage delivery, patients suffer from various radiation-induced complications, among which are toxicities to the nervous tissues in the head and neck area. Radiation-mediated neuropathies manifest as a result of increased oxidative stress-mediated apoptosis, neuroinflammation and altered cellular function in the nervous tissues. Eventually, molecular damage results in the formation of fibrotic tissues leading to susceptible loss of function of numerous neuronal substructures. Neuropathic sequelae following irradiation in the head and neck area include sensorineural hearing loss, alterations in taste and smell functions along with brachial plexopathy, and cranial nerves palsies. Numerous management options are available to relieve radiation-associated neurotoxicities notwithstanding treatment alternatives that remain restricted with limited benefits. In the scope of this review, we discuss the use of variable management and therapeutic modalities to palliate common radiation-induced neuropathies in head and neck cancers.

Evaluating Post-Radiotherapy Laryngeal Function with Laryngeal Videostroboscopy in Early Stage Glottic Cancer

Objective

Dysphonia is common among patients with early stage glottic cancer. Laryngeal videostroboscopy (LVS) has not been routinely used to assess post-radiotherapy (RT) voice changes. We hypothesized that LVS would demonstrate improvement in laryngeal function after definitive RT for early-stage glottic cancer.

Study design

Blinded retrospective review of perceptual voice and stroboscopic parameters for patients with early glottic cancer and controls.

Setting

High-volume, single-institution academic medical center.

Subjects and methods

Fifteen patients underwent RT for Tis-T2N0M0 glottic cancer and were evaluated with serial LVS exams pre- and post-RT. Stroboscopic assessment included six parameters: vocal fold (VF) vibration, VF mobility, erythema/edema, supraglottic compression, glottic closure, and secretions. Grade, roughness, breathiness, asthenia, strain (GRBAS) voice perceptual scale was graded in tandem with LVS score. Assessments were grouped by time interval from RT: pre-RT, 0–4, 4–12, and >12 months post-RT.

Results

60 LVS exams and corresponding GRBAS assessments were reviewed. There were significant improvements in ipsilateral VF motion (P = 0.03) and vibration (P = 0.001) and significant worsening in contralateral VF motion (P < 0.001) and vibration (P = 0.008) at >12 months post-RT. Glottic closure significantly worsened, most prominent >12 months post-RT (P = 0.01). Composite GRBAS scores were significantly improved across all post-RT intervals.

Conclusion

LVS proved to be a robust tool for assessing pre- and post-RT laryngeal function. We observed post-RT improvement in ipsilateral VF function, a decline in contralateral VF function, and decreased glottic closure. These results demonstrate that LVS can detect meaningful changes in VF and glottic function and support its use for post-RT evaluation of glottic cancer patients.

[Head and neck intensity-modulated radiation therapy: Normal tissues dose constraints. Pharyngeal constrictor muscles and larynx]

Radio-induced pharyngolaryngeal chronic disorders may challenge the quality of life of head and neck cancer long survivors. Many anatomic structures have been identified as potentially impaired by irradiation and responsible for laryngeal edema, dysphonia and dysphagia. Some dose constraints might be plausible such as keeping the mean dose to the pharyngeal constrictor muscles under 50 to 55Gy, the mean dose to the supra-glottic larynx under 40 to 45Gy and, if feasible, the mean dose to the glottic larynx under 20Gy. A reduction of the dose delivered to the muscles of the floor of the mouth and the cervical esophagus would be beneficial as well. Nevertheless, the publications available do not provide an extensive enough level of proof. One should consider limiting as low as possible the dose delivered to these structures without compromising the quality of irradiation of the target tumor volumes.

Early Cellular Response to Radiation in Human Vocal Fold Fibroblasts

OBJECTIVES

Radiation therapy is a common treatment strategy for laryngeal carcinoma. However, radiation is not without adverse side effects, especially toward healthy vocal fold tissue, which can lead to long-term impairments in vocal function. The objective of this preliminary study was to investigate early responses of healthy human vocal fold fibroblasts (VFF) to radiation.

METHODS

VFF were exposed to a single or fractionated dose radiation scheme. Nonradiated VFF served as controls. Morphology of radiated and control VFF was subjectively examined. Quantitative polymerase chain reaction was used to evaluate the effect of radiation on extracellular matrix and inflammatory-related genes. VFF viability was investigated using a LIVE/DEAD and clonogenic assay.

RESULTS

Single or fractioned dose radiated VFF were morphologically indistinguishable from control VFF. No significant differences in gene expression were observed following either radiation scheme and as compared to controls. Clonogenic assay revealed reduced VFF viability following the fractionated but not single dose scheme. No changes in viability were detected using the LIVE/DEAD assay.

CONCLUSIONS

We present one of the first investigations to evaluate early responses of healthy VFF to radiation. Findings will contribute to a growing body of literature seeking to elucidate the biological mechanisms underlying voice changes following radiation therapy for laryngeal carcinoma.

RETRACTED: Laryngeal Function After Radiation Therapy

Laryngeal function after oncologic treatment is a key aspect and focus of interest in the contemporary management of head and neck cancers. Although historically the treatment of most locally advanced laryngeal cancers has been total laryngectomy, recent innovations in radiation therapy and combined chemotherapy and radiation therapy have shown that organ and function preservation can be achieved with good oncologic outcomes. Technical improvements, along with better understanding of tumor biology and dose tolerance of critical organs involved in speech and swallowing function, have paved the way for better outcomes. This article reviews in comprehensive detail the recent data of laryngeal function after radiotherapy.