THE SEQUENCE OF VESSEL LIGATION AFFECTS TUMOR RELEASE INTO THE CIRCULATION

Objective: Whether the sequence of pulmonary vein and artery ligation in pulmonary lobectomy for carcinoma affects intraoperative hematogeno us cancer cell dissemination is not known. We examined whether vessel ligation sequence affects the presence of circulating cancer cells as reflected by carcinoembryonic antigen messenger ribonucleic acid. Meth ods: We assayed for the transcripts of carcinoembryonic antigen messen ger ribonucleic acid by reverse-transcriptase polymerase chain reactio n in peripheral blood taken before, during, and after operation from 3 0 patients with non-small-cell lung cancer who underwent a curative lo bectomy and from six patients,vith limited-stage small-cell lung cance r who were treated initially with chemotherapy followed by lobectomy, Each patient was randomly assigned before the operation to have either pulmonary vein ligation or pulmonary artery ligation first. Blood tak en from 10 patients with interstitial pulmonary fibrosis who underwent an open lung biopsy and 41 healthy subjects served as a control. Resu lts: No control samples were positive for transcripts. Sixteen of the preoperative blood samples from the 30 patients with non-small-cell ca ncers were positive. Of these 16, eight samples remained positive even after lobectomy was performed; the remaining eight samples (four in e ach ligation group) became negative. Of the 14 initially negative samp les (seven in each ligation group), nine samples became positive durin g the operation. Such conversion during the operation was more common with arterial ligation first (six patients, 85.7%) than with venous li gation first (three patients, 42.9%), Samples from all six patients wi th small-cell cancer were positive before the operation, and five of s ix samples remained positive after the operation. Conclusions: Many pa tients with non-small-cell lung cancer have systemic disease even when they were thought to have resectable tumors. Ligating the pulmonary v ein before ligating the artery may lessen intraoperative hematogenous dissemination. Most small-cell lung cancers represent systemic disease even when considered resectable.