A. L. Madenci1, G. Z. Li1, C. B. Weldon2 1Brigham And Women’s Hospital,Boston, MA, USA 2Children’s Hospital Boston,Boston, MA, USA
Introduction: Treatment of JMG stems from experience with pharmacologic agents, immunoglobulins, and surgery among adults. Thymectomy may eliminate the production of auto-antibodies, but its role among pediatric patients has never been defined by a prospective, randomized trial. We performed a systematic review to evaluate the complications and outcomes of thymectomy for JMG.
Methods: We performed a computerized search of MEDLINE from January 2000 to March 2015, supplemented with manual searches. Using a priori criteria, we evaluated 118 studies. Case series with fewer than 10 thymectomies were excluded. Data extraction was performed by independent reviewers and included demographic characteristics, timing of thymectomy, serology data, severity of JMG, peri-operative complications, surgical pathology, study design, and potential confounders.
Results: Twelve retrospective studies met inclusion criteria. Of 653 total participants with JMG, 400 (61%) underwent thymectomy. The majority of thymectomies were performed via transsternal approach (n=295, 69%). Median (or mean) time to thymectomy was less than one year in 4 (44%) of 9 studies that specified time to thymectomy. Pre-operatively, patients were primarily Osserman stage I (n=135, 45%), followed by stages II (n=99, 33%), III (n=47, 16%), and IV (n=21, 7%). Elevated anti-acetylcholine receptor (AChR) antibodies were found in 87% (n=65/75) of thymectomized patients tested. Surgical pathology most often showed thymic hyperplasia (n=283, 87%), followed by normal thymus (n=35, 11%), and thymoma (n=8, 2%). Mean post-operative follow-up ranged from 2 to 5 years. Post-operative complications were not well documented. Post-operative improvement in JMG severity was recorded in 89% (n=281/316), including 28% (n=90/316) patients with complete sustained remission. Twenty-four (8%) patients had unchanged symptom severity post-operatively and nine (3%) patients had worsening of symptoms post-operatively. Two patients died post-operatively. Comparisons of thymectomy to non-operative management were mixed. One study reported a trend toward higher remission rate with thymectomy (55% vs. 38%, p=0.06). A second reported similar incidences of complete remission with and without thymectomy. One study found no effect of anti-AChR antibody status on response to thymectomy. Outcomes specific to surgical pathology findings were limited. No study stratified outcome of thymectomy by severity of JMG or timing of thymectomy for JMG.
Conclusion: Existing data studying thymectomy for JMG is entirely retrospective and does not support a clear benefit toward decreasing severity of disease. Reported complications were rare. Overall, the included studies were limited by power and heterogeneity with respect to timing of surgery, serology, patient age, and severity of JMG. Prospective, randomized study of thymectomy for JMG is warranted.