P33: Predictive factors of extended thymectomy for myasthenia gravis
Naoya Himuro, Takao Minakata, Yutaka Oshima, Yuri Tomita, Daisuke Kataoka, Shigeru Yamamoto, Mitsutaka Kadokura
Background: Extended thymectomy as a treatment strategy in myasthenia gravis (MG) is supported by some reports. Improvement in myasthenic symptoms after extended thymectomy occurs in 60% of patients, but improvement factors of extended thymectomy for MG remain controversial.
Methods: We reviewed the clinical outcomes of 28 patients (11 males, 17 females; median age: 57 years) who underwent extended thymectomy for MG at our hospital between 2005 and 2014. We analyzed the following factors influencing outcome: age, gender, Myasthenia Gravis Foundation of America (MGFA) clinical classification, serum level of anti-acethylcholine receptor antibody, presence of thymoma, medication requirements before and after extended thymectomy, and duration from onset to surgery.
Results: There was complete remission in 3 patients (10.7%), palliation in 17 patients (60.7%), no change in 5 patients (17.9%), deterioration in 3 patients (10.7%), and death in 2 patients (7.1%). The preoperative MGFA clinical classifications were I, IIa, IIb, IIIa, and V in 4, 17, 1, 3, and 3 patients, respectively. There were 13 nonthymomatous patients and 15 thymomatous patients. Preoperative median serum level of anti-acethylcholine receptor antibody was 20 nmol/mL, and 24 patients received preoperative steroid administration (85.7%). Patients receiving preoperative steroid administration showed significant postoperative improvement in myasthenic symptoms (P=0.035). There was a tendency for improved myasthenic symptoms in males and patients with MGFA clinical classification IIa (P=0.052 and P=0.078, respectively). Age of the patient, serum level of anti-acethylcholine receptor antibody, presence or absence of thymoma, and duration from onset to surgery were not found to be significant prognostic factors.
Conclusions: The present study showed that extended thymectomy with preoperative steroid administration is an effective therapy for MG. Further studies based on a larger series are needed to confirm these preliminary data.
Keywords: Steroid; extended thymectomy; myasthenia gravis (MG); predictive factors
doi: 10.3978/j.issn.2072-1439.2015.AB102
