Identifying risk factors for L'Hermitte's sign after IMRT for head and neck cancer

Neurological complications of modern radiotherapy for head and neck cancer

Radiotherapy is one of the mainstay treatment modalities for the management of non-metastatic head and neck cancer (HNC). Notable improvements in treatment outcomes have been observed in the recent decades. Modern radiotherapy techniques, such as intensity-modulated radiotherapy and charged particle therapy, have significantly improved tumor target conformity and enabled better preservation of normal structures. However, because of the intricate anatomy of the head and neck region, multiple critical neurological structures such as the brain, brainstem, spinal cord, cranial nerves, nerve plexuses, autonomic pathways, brain vasculature, and neurosensory organs, are variably irradiated during treatment, particularly when tumor targets are in close proximity. Consequently, a diverse spectrum of late neurological sequelae may manifest in HNC survivors. These neurological complications commonly result in irreversible symptoms, impair patients' quality of life, and contribute to a substantial proportion of non-cancer deaths. Although the relationship between radiation dose and toxicity has not been fully elucidated for all complications, appropriate application of dosimetric constraints during radiotherapy planning may reduce their incidence. Vigilant surveillance during the course of survivorship also enables early detection and intervention. This article endeavors to provide a comprehensive review of the various neurological complications of modern radiotherapy for HNC, summarize the current incidence data, discuss methods to minimize their risks during radiotherapy planning, and highlight potential strategies for managing these debilitating toxicities.

A systematic review of the symptomatic management of Lhermitte's phenomenon

INTRODUCTION

Lhermitte's phenomenon (LP) is a transient shock-like sensation that radiates down the spine into the extremities, usually with neck flexion. The potential efficacy and tolerability of various symptomatic therapies in the management of LP have not been systematically reviewed previously.

METHOD

A systematic review was conducted using PubMed, EMBASE, and the Cochrane Library from inception to August 2022 for peer-reviewed articles describing the treatment of patients with Lhermitte's phenomenon. The review adheres to the PRISMA guidelines and was registered on PROSPERO.

RESULTS

This systematic review included sixty-six articles, which included 450 patients with LP. Treatment of the underlying cause varied by aetiology. Whilst LP is most commonly considered in the context of structural pathology of the cervical cord, medication-induced LP was a common theme in the literature. The most common cause of medication-induced LP was platinum-based chemotherapy agents such as cisplatin and oxaliplatin. In medication-induced LP, symptoms typically resolved with cessation of the causative agent. Non-pharmacological treatment options were associated with mild-moderate symptomatic improvement. The most commonly used agents to treat patients with LP were carbamazepine and gabapentin, which resulted in variable degrees of symptomatic benefit.

CONCLUSIONS

No randomised studies currently exist to support the use of symptomatic therapies to treat LP. Observational data suggest that some therapies may yield a symptomatic benefit in the management of LP. However, this systematic review identified a significant paucity of evidence in the literature, which suggests that further controlled studies are needed to investigate the optimal management of this common neurologic phenomenon.

Trimodality therapy of malignant pleural mesothelioma with helical tomotherapy

OBJECTIVE

The purpose of this study was to determine the efficacy and tolerability of hemithoracic radiotherapy implemented with helical tomotherapy (HTT) in malignant pleural mesothelioma (MPM) patients.

METHODS

Between October 2018 and December 2020, data from 11 MPM patients who received trimodality therapy, including lung-sparing surgery (pleurectomy-decortication, P/D), adjuvant chemotherapy (cisplatin+ pemetrexed), and radiotherapy, were retrospectively reviewed. HTT was used to deliver a total of 30 Gy, 50-54 Gy or 59.4-60 Gy to R2 disease with 1.8-2 Gy daily doses. Descriptive data are presented in number (percentage) or median (minimum- maximum). The Kaplan-Meier method was used to calculate survival data. In patients with toxicities, the risk organ doses were compared using the Mann-Whitney U test.

RESULTS

The median follow-up was 20.5 (12-30) months. Two-year local control, disease-free, and overall survival rates were 48.5%, 49%, and 77.9%, respectively. The median prescribed dose for planning target volume (PTV) was 50.4±8.7 (30-60) Gy. Mean dose (D_mean) of total lung was 19.9±6 (10.4-26) Gy; the V20 (%) of ipsilateral and contralateral lungs were 89.±11.2 (62.7-100) and 0.7±2.1 (0.49-5.9), respectively. Esophageal D_mean and maximum doses (D_max) were found as 21.7±8.4 (7.4-34) and 53.1±10.4 (25.4-64.4) Gy, respectively. V30 (%) and Dmean of heart were 22.3%±13.4% (3.9-47) and 21±5.7 (10.8-29.3) Gy, respectively. D_max of medulla spinalis (MS) was 38.6± 1.3 (13.7-48) Gy. Grade 1-2 radiation pneumonitis (RP) developed in 4 (36.4%) and esophagitis in 2 (18.2%) patients. RP was found to be associated with MS and esophageal doses (p<0.05). Myelitis was diagnosed in 1 (9.1%) patient (MS D_max: 29 Gy).

CONCLUSION

HTT can be used as part of trimodality therapy for MPM patients with acceptable toxicities. MS and esophageal doses should be considered for radiation pneumonitis risk, and new dose constraints for these organs should be defined.

Head and neck cancer survivorship consensus statement from the American Head and Neck Society

OBJECTIVES

To provide a consensus statement describing best practices and evidence regarding head and neck cancer survivorship.

METHODS

Key topics regarding head and neck cancer survivorship were identified by the multidisciplinary membership of the American Head and Neck Society Survivorship, Supportive Care & Rehabilitation Service. Guidelines were generated by combining expert opinion and a review of the literature and categorized by level of evidence.

RESULTS

Several areas regarding survivorship including dysphonia, dysphagia, fatigue, chronic pain, intimacy, the ability to return to work, financial toxicity, lymphedema, psycho-oncology, physical activity, and substance abuse were identified and discussed. Additionally, the group identified and described the role of key clinicians in survivorship including surgical, medical and radiation oncologists; dentists; primary care physicians; psychotherapists; as well as physical, occupational, speech, and respiratory therapists.

CONCLUSION

Head and neck cancer survivorship is complex and requires a multidisciplinary approach centered around patients and their caregivers. As survival related to head and neck cancer treatment improves, addressing post-treatment concerns appropriately is critically important to our patient's quality of life. There continues to be a need to define effective and efficient programs that can coordinate this multidisciplinary effort toward survivorship.

Radiotherapy-Specific Chronic Pain Syndromes in the Cancer Population: An Evidence-Based Narrative Review

While radiation therapy is increasingly utilized in the treatment paradigm of many solid cancers, the chronic effects of radiation therapies are poorly characterized. Notably, understanding radiation-specific chronic pain syndromes is paramount given that the diagnosis and management of these conditions can serve to prevent long-standing functional impairments, optimize quality of life, and even allow for continued radiotherapy candidacy. These radiation-specific chronic pain phenomena include dermatitis, mucositis, enteritis, connective tissue fibrosis, lymphedema, and neuropathic pain syndromes. It is necessary to maintain a low threshold of suspicion for appropriately diagnosing these conditions as there exists a variance in when these symptoms arise after radiation. However, we present key epidemiological data delineating vulnerable cancer populations for each pain syndrome along with the available evidence for the management for each specific condition.

[Concurrent chemoradiotherapy for head neck cancers. Should organs at risk dose constraints be revisited ?]

Concurrent chemoradiotherapy improves the outcome of locally advanced head and neck cancers and the current reference chemotherapy is cisplatin. These results are obtained at the cost of increased toxicities. To limit the risk of toxicity, organ at riskdose constraints have been established starting with 2D radiotherapy, then 3D radiotherapy and intensity-modulated radiotherapy. Regarding grade ≥3 acute toxicities, the scientific literature attests that concurrent chemoradiotherapy significantly increases risks of mucositis and dysphagia. Constraints applied to the oral mucosa volume excluding the planning target volume, the pharyngeal constrictor muscles and the larynx limit this adverse impact. Regarding late toxicity, concurrent chemoradiotherapy increases significantly the risk of postoperative neck fibrosis and hearing loss. However, for some organs at risk, concurrent chemotherapy appears to increase late radiation induced effect, even though the results are less marked (brachial plexus, mandible, pharyngeal constrictor muscles, parotid gland). This additional adverse impact of concomitant chemotherapy may be notable only when organs at risk receive less than their usual dose thresholds and this would be vanished when those thresholds are exceeded as seems to be the situation for the parotid glands. Until the availability of more robust data, it seems appropriate to apply the principle of delivering dose to organs at risk as low as reasonably achievable.

Multiple sclerosis as differential diagnosis of radionecrosis for post-irradiation brain lesions: A case report

INTRODUCTION

Demyelination can occur after brain radiotherapy in tissue adjacent to irradiated tumours. To date, no correlation has been found between conventional-dose radiotherapy and the development of multiple sclerosis, but radiotherapy could be a triggering factor among women with known multiple sclerosis. To the best of our knowledge, this is the first well-documented case of this association with a dosimetric analysis.

CASE PRESENTATION

The case we report here describes the development of multiple sclerosis in a 36-year-old woman without significant past medical history 3 months after the last session of fractionated stereotactic radiotherapy for a pituitary macroadenoma. Our dosimetric analysis suggests that all the multiple sclerosis lesions occurred in the brain regions irradiated with a mean biologically effective dose (BED2) of 33.9 Gy (27.3-49.6 Gy).

CONCLUSION

Consequently special caution towards radiotherapy is required among patients with demyelinating illnesses or for 35-45-year-old women who are at risk. In addition, multiple sclerosis lesions can look like metastases. We should therefore keep differential diagnoses in mind in order not to make mistakes that would delay treatment.

Anatomical change during radiotherapy for head and neck cancer, and its effect on delivered dose to the spinal cord

•

A cohort of 133 head & neck cancer patients treated with TomoTherapy was examined.

•

Differences between planned and delivered maximum spinal cord dose were small.

•

Substantial weight loss and anatomical change during treatment was observed.

•

No link between weight loss or anatomical change, and dose differences was seen.

Background and purpose

The impact of weight loss and anatomical change during head and neck (H&N) radiotherapy on spinal cord dosimetry is poorly understood, limiting evidence-based adaptive management strategies.

Materials and methods

133 H&N patients treated with daily mega-voltage CT image-guidance (MVCT-IG) on TomoTherapy, were selected. Elastix software was used to deform planning scan SC contours to MVCT-IG scans, and accumulate dose. Planned (D_P) and delivered (D_A) spinal cord D_2% (SCD_2%) were compared. Univariate relationships between neck irradiation strategy (unilateral vs bilateral), T-stage, N-stage, weight loss, and changes in lateral separation (LND) and CT slice surface area (SSA) at C1 and the superior thyroid notch (TN), and ΔSCD_2% [(D_A – D_P) D_2%] were examined.

Results

The mean value for (D_A – D_P) D_2% was −0.07 Gy (95%CI −0.28 to 0.14, range −5.7 Gy to 3.8 Gy), and the mean absolute difference between D_P and D_A (independent of difference direction) was 0.9 Gy (95%CI 0.76–1.04 Gy). Neck treatment strategy (p = 0.39) and T-stage (p = 0.56) did not affect ΔSCD_2%. Borderline significance (p = 0.09) was seen for higher N-stage (N2-3) and higher ΔSCD_2%. Mean reductions in anatomical metrics were substantial: weight loss 6.8 kg; C1LND 12.9 mm; C1SSA 12.1 cm²; TNLND 5.3 mm; TNSSA 11.2 cm², but no relationship between weight loss or anatomical change and ΔSCD_2% was observed (all r² < 0.1).

Conclusions

Differences between delivered and planned spinal cord D_2% are small in patients treated with daily IG. Even patients experiencing substantial weight loss or anatomical change during treatment do not require adaptive replanning for spinal cord safety.