Thymectomy: A Trivalent Surgical Approach?

This issue of the Thoracic and Cardiovascular Surgeon is focused on the surgical treatment of thymic disease. We invited three reviews by experienced surgeons to describe the current state of open and minimal invasive surgical approaches for benign and neoplastic thymic lesions. Professor Erino Rendina and his colleagues Professor Federico Venuta and Drs. Giulio Maurizi and Antonio D'Andrilli at La Sapienza University in Rome summarize the role of transternal thymectomy.[1] Professor Tommaso Mineo and Dr. Vincenzo Ambrogi at Tor Vergata University in Rome describe the thoracoscopic approach.[2] Dr. Jens Rückert with coauthors Drs. Marc Swierzy and Mahmoud Ismail at the Hospital Charité in Berlin outline their experience with robotic-assisted resection.[3] This snapshot of present-day management emphasizes the robust presence of three distinct techniques for total thymectomy and the evolving treatment standards for three separate conditions: myasthenia gravis (MG), early thymoma surrounded by an intact capsule or fat, and locally advanced thymoma or thymic carcinoma involving adjacent structures, including pericardium, lung or superior mediastinal vessels.

From these succinct reviews, we draw several conclusions:

1. Complete or “maximal” thymectomy for immunological disease is accomplished by any of the three techniques. Where patients demand a less invasive operation, however, sternotomy rates are expected to decline.

2. The treatment of early thymoma remains controversial since resection by any of the above techniques is feasible and outcome for minimal invasive techniques is documented in multiple surgical series. Transternal thymectomy combines a predictable oncological result with a somewhat prolonged recovery. For minimal invasive operations, pleural tumor dissemination as a technical complication of thoracoscopic dissection[4] remains an unacceptable, catastrophic operative event.

3. The resection of locally advanced thymic tumors by an approach other than sternotomy occurs in oncologically uncharted territory. At present, there is no evidence to support either thoracoscopy or robotic-assisted resection for locally invasive thymoma or thymic carcinoma. Complete resection is a key to long-term survival and must not be subjugated to secondary goals related to surgical approach.

4. The relative preference of a robotic-assisted technique over thoracoscopy is sometimes stated but not substantiated. Mineo and Ambrogi hint in their review at a transient role for thoracoscopy.[2] Performing surgical tasks in the seated position using both eyes offers obvious advantages, while equipment expense and rigidity as well as the complexity of imparting surgical skills to the next generation remain a present disadvantage of robotic assistance.

To develop a cogent synthesis for a future in which the surgeon selects the optimal technique for each condition we need comparative studies despite the low incidence of thymoma and MG, a wide availability of presently expensive robotic equipment, and versatile surgeons trained in every technique. Some of these challenges may be resolved with collaborative efforts as offered by the International Thymic Malignancies Interest Group. In the absence of data, current differences and the coexistence of multiple techniques are expected to persist for years to come.

In the second segment, original contributions are published on the outcome of surgical therapy for thymoma and thymic cancer. In a retrospective study comparing video-assisted thoracoscopic and open resection in 27 patients with clinical stage I thymoma, Maniscalco and colleagues report a shorter hospital stay but no other advantage after thoracoscopic intervention.[5] Exploring the limits of minimal invasive resection, Zhang and colleagues report on short-term results for locally advanced thymoma not involving the mediastinal vessels.[6] Resection was completed in every patient and bilateral mediastinal dissection appears to be safe. The obligatory opening of both pleural spaces to the tumor bed, often deliberately avoided during sternotomy, may increase the risk of pleural recurrence. Two studies investigate the outcome of locally advanced and aggressive disease. In a single-institution report of 25 patients with thymic carcinoma of varying histology, Tagawa and colleagues achieve complete resection in two-thirds of patients, mostly those with Masaoka stage I to III, and a 10-year survival of 63% during a mean follow-up of 76 months.[7] These results support complete resection in limited-stage thymic carcinoma. Bölükbas and colleagues report surgical resection in a small series of patients with Masaoka stage IVa thymoma with the intent to avoid pneumonectomy.[8] The authors bend accepted oncological rules as tumor observed at the time of resection is given a clinical stage and extent of resection for individual patients is reported both as R0 and R1 for separate portions of the specimen. These unorthodox and confusing methods diminish the impact of their study. Long-term survival is reported.

We hope you find this issue stimulating and educating.

• References

• 1 Maurizi G, D'Andrilli A, Sommella L, Venuta F, Rendina EA. Transsternal thymectomy. Thorac Cardiovasc Surg 2015; 63 (3) 178-186
• 2 Mineo TC, Ambrogi V. Video-assisted thoracoscopic thymectomy surgery: Tor Vergata experience. Thorac Cardiovasc Surg 2015; 63 (3) 187-193
• 3 Rueckert J, Swierzy M, Badakhshi H, Meisel A, Ismail M. Robotic-assisted thymectomy: surgical procedure and results. Thorac Cardiovasc Surg 2015; 63 (3) 194-200
• 4 Kimura T, Inoue M, Kadota Y , et al. The oncological feasibility and limitations of video-assisted thoracoscopic thymectomy for early-stage thymomas. Eur J Cardiothorac Surg 2013; 44 (3) e214-e218
• 5 Maniscalco P, Tamburini N, Quarantotto F, Grossi W, Garelli E, Cavallesco G. Long-term outcome for early stage thymoma: comparison between thoracoscopic and open approaches. Thorac Cardiovasc Surg 2015; 63 (3) 201-205
• 6 Zhang G, Li W, Chai Y , et al. Bilateral video-assisted thoracoscopic thymectomy for Masaoka stage III thymomas. Thorac Cardiovasc Surg 2015; 63 (3) 206-211
• 7 Tagawa T, Suzuki H, Nakajima T , et al. Long-term outcomes of surgery for thymic carcinoma: experience of 25 cases at a single institution. Thorac Cardiovasc Surg 2015; 63 (3) 212-216
• 8 Bölükbas S, Eberlein M, Oguzhan S, Schirren M, Sponholz S, Schirren J. Extended thymectomy including lung-sparing pleurectomy for the treatment of thymic malignancies with pleural spread. Thorac Cardiovasc Surg 2015; 63 (3) 217-222