Could thymomectomy be a reasonable option for non-myasthenic thymoma patients?

Background: Complete resection is the mainstay of treatment for thymoma, but few studies have investigated the extent of resection on normal thymus. Extended thymectomy is considered the treatment of choice for myasthenic patients with thymoma, while the optimal therapy for non-myasthenic patients is still a matter of debate. The aim of this retrospective study was to compare extended thymectomy vs. thymomectomy in non-myasthenic thymoma patients for (I) oncological outcome, (II) multicentric thymoma occurrence and (III) postoperative myasthenia gravis (MG) development. Methods: A retrospective comparative study was conducted on 92 non-myasthenic patients with completely resected thymoma, according to the extent of resection: extended thymectomy (70 patients) vs. R0-mediastinal thymomectomy (22 patients). Clinical and pathological characteristics, oncological outcome and postoperative MG occurrence were compared between the two study groups. Results: We did not observe any significant differences in gender, age, symptomology, preoperative chemotherapy, histology, tumour size, adjuvant therapy or complications. There were no recorded postoperative mortalities. Stage distribution was different between the two groups: similar percentages of early stage thymoma for both groups were present, but there was a prevalence of stage III for extended thymectomy and stage IV for thymomectomy (P < 0.01). At a median follow-up of 77.4 months (range 1-255 months), no statistically significant differences were recorded in local recurrence (P=0.396), thymoma related deaths (P=0.504), multicentric thymoma occurrence (P=0.742) and postoperative MG development (P=0.343). A high preoperative anti-acetylcholine receptor antibodies (ARAb) serum titer assay was statistically correlated with postoperative MG occurrence (r=0.49, P < 0.05). Conclusions: Thymomectomy appears to be a valid treatment option for non-myasthenic thymoma patients, as this procedure was associated to the same 5-year oncological results, compared to extended thymectomy, for both stage I-II small thymomas and patients with giant unilateral masses, as well as advanced diseases. Moreover, thymomectomy was not associated to an increased rate of postoperative MG.