Invited commentary

Abstract

Thymoma associated with myasthenia gravis (MG) is a rare condition, though of great interest for thoracic surgeons. To improve the understanding of rare clinical entities we can either pursue multicentric studies or rely on single institution reviews. The first method suffers from an interobserver bias, while the second usually extends over many years and necessarily has a time bias. In a disease like thymoma with MG, which is markedly impacted by institutional and personal experience and expertise, interoperator bias is remarkable whereas time bias is often acceptable.This paper from López-Cano and colleagues is an excellent example of the latter type of study. In this rigorously studied series, we find statistically significant confirmation of anecdotal data on thymoma with MG indicating that thymoma histology, severity of MG, and advanced age are negative prognostic factors. On the other hand, we have confirmation that thymoma with MG has very good “oncological” outcome. The relationship between severity of the tumor and that of MG is also well elucidated. If we look at the causes of death, we notice that as much as 47% of demises (18 of 38) were due to causes not related to neither thymoma nor MG. Only 6 patients (15%) died of thymoma, whereas 14 (36%) died of MG. This data confirms that in the long-term, patients with thymoma and MG are most likely to have problems from MG rather than from their tumor. The separate analysis of the three decades covered by this study also indicates that the more the thymectomy is extended, the less are fatal MG crises likely to occur. Therefore, an important message in this study is that not only “oncological” radicality should be pursued, but also the extension of thymectomy intended to cure MG plays an important role. Thymoma associated with myasthenia gravis (MG) is a rare condition, though of great interest for thoracic surgeons. To improve the understanding of rare clinical entities we can either pursue multicentric studies or rely on single institution reviews. The first method suffers from an interobserver bias, while the second usually extends over many years and necessarily has a time bias. In a disease like thymoma with MG, which is markedly impacted by institutional and personal experience and expertise, interoperator bias is remarkable whereas time bias is often acceptable. This paper from López-Cano and colleagues is an excellent example of the latter type of study. In this rigorously studied series, we find statistically significant confirmation of anecdotal data on thymoma with MG indicating that thymoma histology, severity of MG, and advanced age are negative prognostic factors. On the other hand, we have confirmation that thymoma with MG has very good “oncological” outcome. The relationship between severity of the tumor and that of MG is also well elucidated. If we look at the causes of death, we notice that as much as 47% of demises (18 of 38) were due to causes not related to neither thymoma nor MG. Only 6 patients (15%) died of thymoma, whereas 14 (36%) died of MG. This data confirms that in the long-term, patients with thymoma and MG are most likely to have problems from MG rather than from their tumor. The separate analysis of the three decades covered by this study also indicates that the more the thymectomy is extended, the less are fatal MG crises likely to occur. Therefore, an important message in this study is that not only “oncological” radicality should be pursued, but also the extension of thymectomy intended to cure MG plays an important role.