Patients who had lymph nodes removed from the neck during cancer care showed more cognitive impairment than expected from general-population estimates in a retrospective study. The finding is an association, not proof that the surgery caused the problems.
The Weill Cornell Medicine report describes a study published Sept. 29 in Neuron. Researchers examined records of 1,035 head-and-neck cancer patients at Montefiore Einstein who underwent cervical lymphadenectomy, the removal of neck lymph nodes, without additional chemotherapy or radiation therapy.
About 18% of patients younger than 65 had documented cognitive impairment within two years after surgery. The researchers compared that with a cited 4% to 6% estimate for people in the same age range in the general population. Among patients older than 65, the study reported 25%, versus a general-population range of 10% to 22%.
Those are comparisons with population estimates, not with a matched group of similar cancer patients who did not have surgery. Other differences between patients and the broader population could affect the results. The records-based design cannot prove that disrupted lymph drainage caused the cognitive problems.
The team separately studied 59 patients at the Technical University of Munich who had the operation without chemotherapy or radiation and underwent brain scans before and after surgery. The scans showed faster widening of the brain's ventricular temporal horns, a structural change consistent with tissue loss. The change was more pronounced after lymph nodes were removed from both sides of the neck.
In animal experiments, a sudden interruption of lymph drainage was followed by fluid buildup, oxidative stress and inflammatory changes in brain tissue. The researchers also observed damaged clumps of synapsin, a protein involved in signaling between nerve cells. Those clumps were different from the hallmark amyloid and tau deposits associated with Alzheimer's disease; the study does not show that the patients developed Alzheimer's.
The researchers said normal lymphatic drainage helps clear waste from the brain and that surgery may interfere with that pathway. They did not see the same harmful molecular changes in an animal model where drainage declined gradually, a distinction that may help guide further experiments but does not establish a treatment for people.
The team plans a prospective study following patients over time to test the connection more directly. The findings are early research and do not by themselves establish that a medically indicated cancer operation should be avoided or changed.
FingerLakes1.com is the region’s leading all-digital news publication. The company was founded in 1998 and has been keeping residents informed for more than two decades. Have a lead? Send it to news@fingerlakes1.com.