Ann Thorac Surg 2007;84:361
© 2007 The Society of Thoracic Surgeons
Correspondence
Reply
Joseph B. Shrager, MD,
Larry R. Kaiser, MD
Division of Thoracic Surgery, University of Pennsylvania School of Medicine, 3400 Spruce St, Philadelphia, PA 19104
(Email: joseph.shrager{at}uphs.upenn.edu).
To the Editor:
We welcome the interest expressed by Drs Jaretski and Sonett [1] in our work [2] on transcervical thymectomy (TCT) in myasthenia gravis (MG). It is appropriate that this important topic should be the center of spirited debate.
We fully agree that the revised definition of complete remission (CR) that we adopted and our inability to use the most recently recommended standards of evaluation of MG symptom status (recommended by Jaretski and others [1]) in our analysis render it difficult to compare our results with those of other groups. For these reasons we have been very careful in the wording of our conclusions. In the Comment section we conclude that our response rates are "... sufficiently high to allow us to recommend this far less morbid and less costly operation as a reasonable choice in the surgical treatment of MG." We go on, in fact, to discuss in detail the evidence supporting the likelihood that response rates are slightly higher after "maximal" thymectomy, although we would like to see an update of the old Kaplan-Meier curve reporting an 81% CR estimate at 7.5 years.
On the issue of our broadened definition of CR, we have given a detailed clinical and statistical explanation within our publication of why we believe that it was appropriate (ie, see second paragraph in the Comment section), which we will not reiterate here, but we stand by this argument. Furthermore, we reported our results in the publication using both this broadened CR and our previous and more restrictive definition of CR, although the latter, admittedly, still does not satisfy to the letter the Myasthenia Gravis Foundation of America (MGFA) definition of "complete stable remission." In fact, the very first paragraph of the Comment section refers only to the results with the more restrictive definition of CR.
On the issue of our failure to use the MGFA "standards of evaluation," there is only so much one can do within a retrospective study design. Once our patients had been classified in the mid to late 1990s (before the MGFA recommendations were proffered), according to a modified Osserman classification, there was no option but to continue with some version of this in subsequent analyses. The MGFA recommendations regarding evaluation of MG will be, without doubt, most useful in prospective studies and in retrospective studies that began enrolling patients after 2000.
We continue to believe (given its dramatically lower morbidity) that a strong argument can be made for TCT even if CR rates are slightly lower than those after transsternal approaches to thymectomy. Whether or not the CR rates are the same, slightly lower, or dramatically lower can only be sorted out by the type of well-controlled, nonrandomized class II study that Jaretski and Sonett [1] describe. We are anxious to participate in the organization and execution of such a study.
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References
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- Jaretski III A, Sonett JR. Evaluation of results of thymectomy for MG requires accepted standards (letter) Ann Thorac Surg 2007;84:360-361.[Free Full Text]
- Shrager JB, Nathan D, Brinster CJ, et al. Outcomes after 151 extended transcervical thymectomies for myasthenia gravis Ann Thorac Surg 2006;82:1863-1869.[Abstract/Free Full Text]
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