Thymomectomy plus total thymectomy versus simple thymomectomy for early-stage thymoma without myasthenia gravis: a European Society of Thoracic Surgeons Thymic Working Group Study

Abstract

OBJECTIVES Resection of thymic tumours including the removal of both the tumour and the thymus gland (thymothymectomy; TT) is the procedure of choice and is recommended in most relevant articles in the literature. Nevertheless, in recent years, some authors have suggested that resection of the tumour (simple thymomectomy; ST) may suffice from an oncological standpoint in patients with early-stage thymoma who do not have myasthenia gravis (MG) (non-MG). The goal of our study was to compare the short- and long-term outcomes of ST versus TT in non-MG early-stage thymomas using the European Society of Thoracic Surgeons thymic database. METHODS A total of 498 non-MG patients with pathological stage I thymoma were included in the study. TT was performed in 466 (93.6%) of 498 patients who had surgery with curative intent; ST was done in 32 (6.4%). The completeness of resection, the rate of complications, the 30-day mortality, the overall recurrence and the freedom from recurrence were compared. We performed crude and propensity score-adjusted comparisons by surgical approach (ST vs TT). RESULTS TT showed the same rate of postoperative complications, 30-day mortality and postoperative length of stay as ST. The 5-year overall survival rate was 89% in the TT group and 55% in the ST group. The 5-year freedom from recurrence was 96% in the TT group and 79% in the ST group. CONCLUSION Patients with early-stage thymoma without MG who have a TT show significantly better freedom from recurrence than those who have an ST, without an increase in postoperative morbidity rate.

Thymomectomy versus complete thymectomy in early-stage non-myasthenic thymomas: a multicentric propensity score-matched study

“…Despite the numerous attempts of defining the various extent of resection, some doubts still persist [ 1 , 3–5 , 10 , 15–19 ]. To avoid confusion or misunderstanding, we tried to synthetize all the definitions proposed in the literature about resection of thymoma with a particular caveat for the limits of conservative surgery.…”

“…Actually, complete thymectomy [ 1 , 3 ] and thymothymectomy [ 10 ], defined as complete removal of the tumour mass en bloc with the entire thymus gland, appear to be the same procedure and represent our technique when we consider extended operations. Zielinski [ 19 ] introduced the maximal thymectomy providing the resection of tumour, thymus gland and mediastinal fat tissue including a neck dissection with sternal lifting performing with a mini-invasive approach.…”

“…The ESTS Thymic working Group Study recently reported that patients with early-stage thymoma without myasthenia gravis performed with complete thymectomy have significantly better oncological outcome compared to patients who received conservative surgery [ 10 ]; however, in this series, the number of simple thymomectomy was relatively inferior compared to the number of extended operations (1:3).…”

“…A 2016 propensity score analysis for stage I thymoma found a difference in the rate of local recurrence without reaching statistical significance [ 8 ], and another 2018 retrospective analysis of stage I-IV by one of us had a comparable 5- and 10-year disease-free survivals [ 9 ]. Furthermore, a recent study of a European Society of Thoracic Surgeons Thymic Working Group Study [ 10 ] differentiated the surgical resection into thymothymectomy and simple thymomectomy: the former representing a complete resection removing both the tumour and entire thymus tissue and the latter the sole resection of the tumour without thymus gland. They concluded that simple thymomectomy was associated with a shorter progression-free survival compared with thymothymectomy [ 10 ].…”

“…Furthermore, a recent study of a European Society of Thoracic Surgeons Thymic Working Group Study [ 10 ] differentiated the surgical resection into thymothymectomy and simple thymomectomy: the former representing a complete resection removing both the tumour and entire thymus tissue and the latter the sole resection of the tumour without thymus gland. They concluded that simple thymomectomy was associated with a shorter progression-free survival compared with thymothymectomy [ 10 ].…”