Delayed lower cranial neuropathy after oropharyngeal intensity‐modulated radiotherapy: A cohort analysis and literature review

Abstract

Background To examine swallowing-related lower cranial nerve palsy (LCNP) in oropharyngeal cancer (OPC) survivors after intensity modulated radiotherapy (IMRT). Methods Patients treated with definitive IMRT (66–72 Gy) were pooled from trial databases. Prospective analyses on parent trials included videofluoroscopy, clinical LCNP examination, and questionnaires pre- and 6-, 12-, and 24-months post-IMRT. Time-to-event and incidence of LCNP was estimated with competing risk methods. Literature review (1977–2015) summarized published LCNP outcomes. Results Three of 59 OPC survivors with a minimum 2-year follow-up developed hypoglossal palsy ipsilateral to the index tumor (median latency: 6.7 years, range: 4.6–7.6). At a median of 5.7 years, cumulative incidence of LCNP was 5%. LCNP preceded progressive dysphagia in all cases. Published studies found median incidence of radiation-associated LCNP was 10.5% after NPC, but no OPC-specific estimate. Conclusions While uncommon, the potential for late LCNP preceding swallowing deterioration highlights the importance of long-term functional surveillance in OPC survivorship.

Swallowing‐related outcomes associated with late lower cranial neuropathy in long‐term oropharyngeal cancer survivors: cross‐sectional survey analysis

“…Thereby, late LCNP was consistently associated with substantial functional morbidity among OPC survivors. These results are not surprising given the degree of swallowing dysfunction previously reported among long‐term OPC survivors in earlier case reports, which suggested that treatment‐related LCNP may play a major role in late RAD and precipitate delayed but extreme oropharyngeal impairment as recorded by MBS studies . These observations also align to numerous reports of significant swallowing dysfunction caused by lower CN deficits among populations (in the absence of head and neck RT) due to traumatic injury, vascular causes, and infection, documented primarily in case reports …”

“…Overall, late LCNP with accompanying dysphagia is a clinical condition of great concern as it does not typically respond well to treatment. With progressive long‐term functional decline with aspiration and recurring aspiration‐pneumonia, long‐standing feeding tube dependence and elective laryngectomy may be required . Therefore, risk reduction and management of late effects like LCNP, late‐RAD, and associated functional toxicities need to be prioritized in contemporary OPC treatment and management.…”

“…An adapted version of the PSS‐HN, a validated, clinician‐rated interview‐based measure of performance status among patients with HNC was included in the survey instrument . The scale was adapted for patient‐reported administration and consisted of questions pertaining to the survivor's diet level and public eating experience .…”

“…Lower cranial neuropathies (LCNP) are a rare but permanent late effect of HNC treatment that injures the glossopharyngeal (IX), vagus, (X), accessory (XI), and/or hypoglossal (XII) nerves . These nerves (except XI) play a pivotal role in the oropharyngeal swallowing mechanism and thereby their damage can contribute to profound functional impairment in terms of dysphagia often with coexisting problems in speech and voice and shoulder impairment.…”

“…Several small published series and case reports consistently describe severe problems in swallowing, eating, and extreme functional impairment in pharyngeal phase of swallowing among survivors with late LCNP, with associated swallowing inefficiency, pharyngeal residue, and silent aspiration. Consequently, about 85% of OPC survivors with late‐RAD develop pneumonia, and more than 60% require long‐term gastrostomy tube placement highlighting the possible extreme functional relevance of late LCNP if it indeed is a driver of late dysphagia …”