Neck lymph node removal linked to increased risk of cognitive decline

A new study led by Weill Cornell Medicine researchers suggests that removing lymph nodes in the neck following head and neck cancer surgery may increase the risk of cognitive decline. The research, published in the journal Neuron, found that patients who underwent cervical lymphadenectomy had a higher incidence of cognitive impairment compared to the general population.

The study's authors explain that this procedure is often performed to prevent cancer spread, but the paper reveals that it can disrupt the brain's waste-clearance system. This disruption can lead to fluid buildup and oxidative stress, which damages cell proteins and triggers inflammation.

Neck lymphedema, or swelling caused by disrupted lymph drainage, is a known complication after lymphadenectomy. However, this study is one of the first to directly examine the impact of impaired lymphatic fluid clearance on the brain. The researchers analyzed records of 1,035 patients who underwent neck lymphadenectomy at Montefiore Einstein, finding that 18% of patients under 65 experienced cognitive impairment within two years of the procedure, compared to a 4% to 6% risk in the general population of the same age group.

Among patients older than 65, 25% of those who underwent surgery developed cognitive impairment, compared to 10% to 22% of the general population. The imaging data from a separate group of 59 patients who underwent cervical lymphadenectomy showed accelerated widening of the ventricular temporal horns in the brain, indicating brain atrophy or shrinkage.

Further research is needed to confirm a direct link between cervical lymphadenectomy and cognitive impairment. The study also conducted animal experiments that demonstrated oxidative stress and inflammation in brain cells when fluid could not drain normally from the brain. Additionally, the researchers found that proteins involved in neuron signaling, such as synapsin, were damaged and clumped together, differing from the plaques and tangles typically associated with Alzheimer's disease.

While this study provides valuable insights, it is important to note that the patient data do not establish a definitive causal relationship. The researchers plan to conduct a prospective study to follow patients over time as they undergo cervical lymph node removal. Potential future treatments may include exploring ways to improve lymphatic drainage, such as transplanting a lymph node from another area of the body to prevent lymphedema.