Does the sequence of pulmonary vasculature ligation have any oncological impact during an anatomical lung resection for non-small-cell lung cancer?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was 'in patients with primary lung carcinoma, does the sequence of pulmonary vasculature ligation during anatomical lung resection influence the oncological outcomes?' A total of 48 papers were found using the reported search, of which 7 represented the best evidence to answer the question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Among six prospective studies included, five of them randomized patients to either pulmonary vein or artery occlusion first during anatomical lung resection, while one study was retrospective. Two reports did not find any difference between pulmonary vein and artery occlusion first during long-term follow-up in terms of either disease recurrence (51 vs 53%, P = 0.7), or 5-year overall survival (54 vs 50%, P = 0.82). One report did not find any difference with regard to circulating tumour cells either after thoracotomy (5.0 vs 3.9, P = 0.4), or after the completion of lobectomy (38.0 vs 70.0, P = 0.23). One report found a higher expression of CD44v6 (P = 0.008) and CK19 (P = 0.05) in patients undergoing pulmonary arterial occlusion first. One report found that pulmonary vein occlusion before that of the pulmonary arterial branches has a favourable outcome on circulating carcino-embryonic antigen (CEA) mRNA in the peripheral blood, while another one did not find a significant difference in circulating levels of CEA mRNA (P = 0.075) and CK19 mRNA (P = 0.086) with either method. Another study reported no correlation between circulating pin1 mRNA levels in peripheral blood after the completion of the resection and the sequence of ligation of pulmonary vessels (9.95 ± 0.91 vs 14.71 ± 1.64, P > 0.05). Based on the two studies assessing the long-term outcome of patients with primary lung cancer undergoing anatomical curative resection, the sequence of ligation of pulmonary vessels does not seem to influence the oncological outcomes or survival. However, the other studies focusing on the influence of these techniques on circulating tumour cells or their molecular products report conflicting results the clinical consequences of which cannot be predicted.