Association between cervical lymph node dissection and dementia: a retrospective analysis

Background: Dementia, characterized by memory loss and cognitive impairment, considerably impacts individuals and society. Our research focused on cervical lymph nodes, crucial for CNS lymphatic drainage, in the context of dementia. We hypothesized that the patients with head and neck cancer (HNC) undergoing cervical lymph node dissection (CLND) may have increased dementia risk due to obstructed lymphatic pathways. Methods: We conducted a retrospective analysis of the electronic medical records from patients over 60 years diagnosed with HNC who underwent CLND between March 2007 and April 2023. We collected demographic data, calculated dementia incidence rates, and compared parameters between patients with and without dementia. Results: Among the 251 patients with HNC who underwent CLND, 234 were men and 17 were women. Nine male patients developed dementia within an average of 50.1 ± 35.3 months post-surgery. The dementia incidence rate was 0.7 per 100 patient-years, with a cumulative incidence of 10.34% over 8.6 years. The CLND patterns were associated with dementia (p = 0.028), with bilateral supraomohyoid neck dissection (SOHND)/modified radical neck dissection (MRND) and unilateral MRND combined with any neck dissection type on the other side presenting higher risks than unilateral MRND/SOHND (p = 0.016). Conclusion: Patients with HNC undergoing bilateral and comprehensive lymph node dissection showed higher dementia risk, highlighting the importance of the neck's lymphatic role in brain health. These findings may guide future surgical practices. © 2024 British Association of Plastic, Reconstructive and Aesthetic Surgeons