Safety of Simultaneous Bilateral Pulmonary Resection for Metastatic Lung Tumors

Discussion

In the present study, we showed that compared with unilateral pulmonary resection for metastatic lung tumors, simultaneous bilateral pulmonary resection is a safe procedure as long as only wedge resection is performed on at least one side. Surgical resection for metastatic lung tumor contributes not only to confirming an exact diagnosis (6) but is also a potentially curative treatment (7-11). However, until the 1960s, patients with bilateral lung lesions were believed to have a poor prognosis, and therefore were not indicated for surgery (12). Advances in preoperative radiographic imaging modalities and improvement of surgical instruments have contributed to an increased applicability of operation for bilateral lung lesions (13). However, it remains unclear whether it is safe to resect bilateral pulmonary metastases simultaneously.

According to a web-based questionnaire by the European Society of Thoracic Surgeons (ESTS) Pulmonary Metastasectomy Working Group in 2008 (14), in the case of bilateral disease, 146 members of ESTS responded that the most favorable approach was bilateral two-staged thoracotomy (66.2%). The second most popular approach, one-stage median sternotomy, was selected by 39 members (26.9%). When approaching bilateral lesions simultaneously, median sternotomy was evaluated as an effective approach in the 1980s (15-17). Roth et al. researched patients who underwent sternotomy for metastatic soft-tissue sarcoma tumors of the lung and concluded that median sternotomy allowed exploration for unsuspected diseases on the opposite side, which avoided the need for a second operation (15). Furthermore, Van der Veen et al. suggested that median sternotomy was chosen for the pulmonary resection because it allows a one-stage complete operation, lower morbidity, and the discovery of hidden metastases (16). However, recent progress in surgical procedures and instruments have encouraged surgeons to perform simultaneous bilateral pulmonary metastasectomy for patients with synchronous bilateral metastatic lung tumors. Previous reports on the risk of bilateral simultaneous pulmonary resection for pulmonary metastases or primary lung tumors are summarized in Table V. Mun et al. surveyed 19 cases with synchronous bilateral multiple lung cancer (18). Five cases underwent median sternotomy and another 14 cases underwent VATS, and all cases underwent wedge resection on at least one side. In two out of 19 cases, postoperative complications (pneumonia and interstitial pneumonia progression) occurred. The report demonstrated that mean postoperative hospitalization was 14.3 days (range=4-113 days); however, it did not mention the duration of chest drainage, which seems critical in considering the safety of simultaneous bilateral lung resection. In addition, Yao et al. reviewed 29 patients who underwent single-stage pulmonary resection under VATS (19) compared to two-stage resections. In terms of postoperative complications, they concluded that the one-stage strategy was more tolerable compared with the two-stage operation (p=0.944). The mean duration of chest tube drainage in patients who underwent the one-stage operation was 4.0±1.2 days, which was not different from that in patients who underwent the two-stage operation. There was a significant decrease in postoperative in-hospital stay for patients who underwent one-stage bilateral pulmonary resection in comparison with that in patients who underwent a two-stage operation (mean=7.3±1.2 vs. 7.3±3.2 days: p=0.009). In our study, the mean operative time and duration of chest tube drainage in the bilateral group was significant longer than that in the unilateral group (both p<0.01). There were no postoperative complications in the bilateral group, and there was no statistical difference in postoperative hospital stay after surgery (p=0.66). These results and previous reports indicate that simultaneous bilateral lung metastasectomy has been a tolerable surgical option compared with two-staged lung metastasectomy.

We also showed that simultaneous bilateral pulmonary metastasectomy with anatomical resection in one side can be safely performed in selected patients. Mean operative time was significantly longer in the WSL group than in the WW group (p=0.03), but there was no statistical difference in blood loss between the groups (50±20 vs. 35±19 g, p=0.58). In terms of postoperative course, duration of drainage and postoperative in-hospital days were not significantly different (p=0.26 and 0.89, respectively). In the present series, we performed two-stage operations for the patients who need bilateral anatomical resections. As Mun et al. suggested (18), we presently think that simultaneous bilateral lobectomy should be performed in two stages because of the invasiveness and risk.

Thomford et al. established the four operative indications for pulmonary metastases from malignant tumors (3). We propose a modified version of Thomford et al.'s criteria for simultaneous bilateral lung metastasectomy in Table VI. The above three indications in Table VI, which are almost same as Thomford et al.'s criteria, are important factors for undertaking pulmonary metastasectomy. The most important indication for undertaking simultaneous bilateral pulmonary metastasectomy is that all pulmonary lesions should be resectable by wedge resection on at least one side. Anatomical pulmonary resection can be performed if the lesion on at least one side is resectable by wedge resection.