Patients with head and neck cancer who had lymph nodes removed from the neck showed higher rates of cognitive impairment than the general population, according to multicenter research led by Weill Cornell Medicine scientists and published September 29 in Neuron. The procedure, called cervical lymphadenectomy, is done to reduce the risk of cancer spreading, and it has not typically been considered a factor in brain health.
The research team followed up the patient data with preclinical work showing a plausible mechanism. Removing those neck lymph nodes appears to interfere with the drainage of cerebrospinal fluid out of the brain, the pathway through which the brain clears metabolic waste. When that drainage is obstructed, fluid builds up and sets off oxidative stress, a molecular process that damages cellular proteins and triggers inflammation.
Dr. Laura Santambrogio, the study's senior author and a professor of radiation oncology at Weill Cornell Medicine, framed the issue in terms of basic plumbing: the body makes lymphatic fluid to flush waste from every organ, the brain included, and when that system falls short the consequences can accumulate over time. Her role as associate director of precision immunology at the Englander Institute of Precision Medicine reflects how much of this work sits at the intersection of immune function and neurodegeneration.
For cancer survivors, the finding raises a question that has received little attention - whether cognitive changes after neck surgery are being recognized and tracked at all. It also adds to a growing line of research treating the brain's waste-clearance system as a mechanism worth watching in dementia, rather than an incidental piece of anatomy.