Thymectomy associated with increased risk of mortality and cancer in adults: NEJM

USA: A recent study has shed light on the health consequences of thymus removal (thymectomy) in adults that were previously considered safe and frequently conducted during cardiothoracic surgery due to the location of the thymus in the chest. 

The study, led by Dr. David T. Scadden from the Center for Regenerative Medicine at Massachusetts General Hospital in Boston, revealed a significant association between thymectomy and increased all-cause mortality and cancer risk in adults. 

The research highlights potential risks associated with thymectomy, the surgical removal of the thymus gland, and emphasizes the ongoing importance of the thymus for adult health.

The study aimed to investigate the outcomes of thymectomy in adults and its impact on mortality, cancer, and autoimmune disease risk. The researchers compared individuals who underwent thymectomy with a matched group of patients who had undergone cardiothoracic surgery without thymectomy. The study analyzed data from 1,420 adults who had thymectomy at Massachusetts General Hospital from 1993 to 2020.

The study's findings were significant and concerning, shedding light on the potential risks associated with thymectomy:

● Thymectomy patients had at least double the risk of all-cause mortality and cancer at 5 years post-surgery compared to the matched cardiothoracic surgery group.

● All-cause mortality: 8.1% vs. 2.8% (RR 2.9, 95% CI 1.7-4.8)

● Cancer: 7.4% vs. 3.7% (RR 2.0, 95% CI 1.3-3.2)

● Autoimmune disease was relatively more common after thymectomy when confounding conditions were excluded (12.3% vs. 7.9%; RR 1.5, 95% CI 1.02-2.2).

Dr. Naomi Taylor, a pediatric oncology expert from the National Cancer Institute, referred to the study as a "landmark" investigation with significant implications for patient care. The findings underscore the importance of preserving the thymus and challenge the notion that thymectomy is safe in adulthood. Previous studies had indicated the ongoing production of T lymphocytes in the adult thymus, and this research supports the notion that the thymus continues to play a crucial role in immune system function.

The study's findings have far-reaching implications for the field of cardiothoracic surgery and beyond. Thymectomy, once thought to be a safe procedure, is now associated with increased risks of mortality, cancer, and autoimmune disease in adults. The study underscores the importance of preserving the thymus, suggesting that it continues to serve vital functions in adulthood. While further research is needed to fully elucidate the mechanisms underlying these associations, this study serves as a critical reminder that medical interventions should be carefully considered and guided by the latest research.

Reference:

New England Journal of Medicine Kooshesh KA, et al "Health consequences of thymus removal in adults" N Engl J Med 2023; DOI: 10.1056/NEJMoa2302892.