We evaluated the risk of RPR for MLC in the present study. RPR was not found to be associated with the risk of postoperative complications, and there was no perioperative mortality. The incidence of postoperative complications with RPR was reported to range from 19–33% in previous studies [1, 3, 4, 9, 10]. Although the incidence of postoperative complications at the second operation in the present study was 29%, all patients with postoperative complications of grade IIIa had air leakage that required pleurodesis. The rate of other complications classified as grades I and II was 14% at the first operation and 9% at the second operation. These findings indicate that severe postoperative complications were relatively rare. The VATS approach for managing lung malignancies has been widely adopted and is reported to be less invasive than thoracotomy [15–21]. Because both the first and second operations were performed via the VATS approach in most cases in the present study, it might have been affected less invasive and physical function maintenance.
In previous studies, the mortality separated by operative procedure was reported; the mortality rate was 34% for pneumonectomy, 7% for lobectomy, 0% for segmentectomy, and 6% for partial resection [10]. The mortality rate might have been lower than in previous studies because there were more cases of partial resection and segmentectomy than lobectomy at the second operation in the present study. Although cases of sublobar resection accounted for more than 80% for second operations, the 8-year overall survival was 78%, suggesting that sublobar resection might have a good prognosis. Furthermore, sublobar resection might maintain the respiratory function and enable a third round of pulmonary resection.
RPR has diagnostic and therapeutic implications. The prevalence of a second malignancy in lung cancer patients investigated in previous studies was reported 1.87%-2.41% [23.24]. Although a histological examination is necessary for cases of metastasis or second primary lung cancer, the histological pattern may have changed in relapse tumors. Molecular assessments, such as gene array analyses or patterns of loss of heterozygosity, are useful for the identification of the independence of lung primaries, underscoring the importance of obtaining acceptable specimens. Furthermore, favorable outcomes were reported for select stage IV NSCLC patients who received complete resection of both the primary lung tumor and metastasis, such as solitary adrenal gland, brain or contralateral lung metastasis [25–27].
A previous study showed that an operation time exceeding two hours was a predictor of postoperative complications [10]. In the present study, an operation time exceeding two hours tended to increase the risk of postoperative complications in our multivariate analysis. Although ipsilateral resection for MLC had a significantly longer operation time than contralateral resection, the incidence of postoperative complications was not significantly different between ipsilateral and contralateral resection (p = 0.88). Therefore, ipsilateral RPR itself might be not predictor of postoperative complications.
The present study was associated with several limitations. First, the study was retrospective in nature and potentially involved unobserved cofounding and selection biases. Second, our study was performed at a single institution, and the study population was relatively small.