Surgery for thymomas: is less worthwhile? A clear answer from the European experience

Radicality is the major goal of any surgeon who deals with a malignancy, and this principle is even more valid in thymomas, whose surgical resection represents the cornerstone of treatment, as the vast majority (>90%) of them is localized [1].

Since the first experiences of great surgeons, who have inextricably linked their name to this field, surgery in thymoma consisted in a complete resection of the tumour together with an extended or radical thymectomy [2, 3].

The underlying rationale was the non-negligible risk in developing postoperative myasthenia gravis or overlooking multi-focal or metastatic thymomas but, most of all, the increased risk of local recurrence due to residual thymic tissue left, which eventually require a second surgery [4, 5].

Nevertheless, more recently, in reason of improvements in imaging and mini-invasive surgical techniques, an increasing number of small thymomas were detected incidentally or less so different authors experienced limited resection for non-myasthenic patients affected by early-stage thymomas with conflicting results [6–8].

Moreover, minimally invasive surgery for anterior mediastinal surgery gained popularity worldwide, paving the way for a more conservative and tissue-sparing technique that may result in a less complex procedure to be harvested by a less invasive approach, which may be associated to decreased operative time and surgical trauma.

In this debated scenario, Guerrera et al. [9] presented a comparison of short and long-term outcomes of patients who underwent simple thymomectomy (ST) and thymo-thymectomy (TT) in non-myasthenic early-stage thymomas, using the European Society of Thoracic Surgeons Thymic Database.

The study's strengths are the large number of patients from 23 different European centres, inclusion of comprehensive data despite a follow-up inferior to 5 years, and the use of propensity-score matching to reduce possible confounding bias, which allowed a selection of 2 patient’s groups comparable in terms of clinical features and pathological tumour’s characteristics.

Unfortunately, data about occurrence of post-operative myasthenia gravis or the presence of multi-focal thymomas are lack also due to the retrospective nature of the study.

Nevertheless, authors demonstrated that patients treated by ST showed the same rate of post-operative complications, 30-day mortality, and postoperative length of stay of those treated by TT; on the other hand, they experienced minor overall survival (5-year overall survival rate was 89% and 55% in the TT and ST groups, respectively) and disease-free survival (5-year FFR was 96% and 79% in the TT and ST groups, respectively) in pathological stage I thymoma.

The study confirms what had been previously published by Nakagawa et al. [8] and Gu et al. [10], for the Japanese Association for Research on the Thymus and Chinese Alliance for Research in Thymoma, respectively. They also reported a higher recurrence rate in patients treated by tissue-sparing procedures for early-stage thymoma by analysing data from multicentre database.

Thymomas, especially those in early stage and in non-myasthenic patients, have a very indolent behaviour, totally atypical compared to other solid tumour, usually affect young people, and show excellent survival rates when radically treated. For this reason, especially in this case, surgery should prevent any possible risk of recurrence or redo surgery and, to date, an extended thymectomy is the only recognized instrument to achieve the goal.

In the last few years, ‘less is more’ turned out to be a fashion that spread rapidly and, although this philosophy has totally changed the approach for most of thoracic pathologies thanks to excellent improvements in the post-operative course and in quality of life; it should be confined to the surgical technique rather than to the oncological extent.

The study by Guerrera et al. has further highlighted this old dogma, showing better oncological results in patients treated in the traditional and more extended way (thymothymectomy) compared to those treated in a more conservative although fashioned approach (thymomectomy) which has not demonstrated either short-term benefits.

Fashion fades, only style remains the same, and surgery is not and must not become a fashion.

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