the treatment of locally advanced non - small cell lung cancer ( nsclc ) , particularly those invading the great vessels and left atrium ( la ) , remains challenging . in selected patients with locally advanced nsclc , complete resection using cardiopulmonary bypass ( cpb ) is sometimes performed . this method may contribute to a favorable prognosis [ 1 , 2 , 3 , 4 , 5 ] . cpb use may be linked to cancer progression because it could induce immunosuppression and tumor dissemination via the cpb circuit [ 6 , 7 ] . therefore , patient selection for cpb is essential . circulating tumor cells ( ctcs ) are surrogate markers for distant metastasis . in nsclc , the presence of ctcs in peripheral blood suggests distant metastases . here , we evaluated preoperative and intraoperative ctc counts in a patient who underwent complete resection using cpb for locally advanced nsclc he was a current smoker ( 20 cigarettes / day ) and had smoked for 40 years . two months later , he consulted a family doctor for his cough ; other symptoms , such as hemosputum , appetite loss , and body weight loss , were absent . chest x - ray showed an abnormal shadow in the left hilum lesion ( fig . 1 ) . chest computed tomography ( ct ) revealed a solid lung tumor in the left lower lobe . contrast - enhanced ct showed that blood flow into the left inferior pulmonary vein could not be visualized ; therefore , we assumed that the tumor was invading the inferior pulmonary vein to the la ( fig . 2 ) . positron emission tomography - ct showed that the lung tumor had very strong uptake , but fortunately , there was no abnormal uptake indicating a distant metastasis ( fig . we considered complete resection , which would be possible under cpb if the tumor was invading the la wall . after thoracotomy , we confirmed that the tumor had invaded the left upper lobe and left inferior pulmonary vein without pleural dissemination . the patient then underwent left pneumonectomy combined with la resection under cpb and complete resection was achieved . samples of 7.5 ml blood were taken to evaluate ctc counts ; one sample was taken from peripheral blood just before the surgery and the other sample was taken from the cpb circuit . the samples of blood were collected in cellsave tubes ( veridex llc , raritan , nj , usa ) and were used for ctc tests . pathological examination showed that the tumor had invaded the left upper lobe and left inferior pulmonary vein and hilum lymph node , indicating tnm stage t4n1m0 . the patient is doing well without tumor recurrence and distant metastases have not been observed for 8 years after the surgery . despite progress in nsclc treatment , clinical outcomes for locally advanced nsclc remain poor , and complete resection is often planned as a part of multimodality therapy . in a case in which a tumor invades a great vessel or la , cpb is required to achieve complete resection . although favorable outcomes have been reported many times of using cpb in locally advanced nsclc [ 1 , 2 , 3 , 4 , 5 ] , cpb can induce immunosuppression and tumor dissemination [ 2 , 3 , 6 ] . muralidaran and co - workers   described poor prognoses in patients when cpb is unplanned . fukuse and co - workers   reported that 3-year survival rates are significantly higher in patients with pathologically n01 nsclc than in those with n23 nsclc ( 37 vs. 0% ) ; therefore , they concluded that complete resection using cpb should be planned in patients with n01 nsclc . with respect to this surgical criteria for locally advanced nsclc , we are hopeful that a 5-year survival rate will be achieved in the present case . however , it is controversial to base the rationale for complete resection using cpb for locally advanced nsclc only on the nodal status . we recommend that complete resection using cpb be performed in patients with a truly local case ; thus , this decision should be made based not only on the n factor but also in the absence of distant metastases . to identify distant metastases , systemic evaluation is usually performed preoperatively ; however , micrometastases may be difficult to be detected using conventional radiology . ctc is known to be a surrogate marker for distant metastases in various cancers . in nsclc , tanaka and co - workers   described ctc count as a predictive factor of distant metastases . here ctc counts in both preoperative peripheral blood and intraoperative cpb circuit were 0/7.5 ml , suggesting an absence of micrometastases . the present case may , therefore , represent a truly local disease , which may have contributed to a favorable prognosis . hasegawa and co - workers recommend that a risk / benefit ratio should be considered for surgical resection using cpb because of its invasiveness and associated prognoses . in a case positive for ctc , the risk / benefit ratio would be toward risk because ctc count suggests the presence of distant metastases . in conclusion , ctc count may be a useful tool to detect micrometastases in patients with locally advanced nsclc in whom planned complete resections using cpb are being considered . because ctc is well recognized as a surrogate for distant metastases , this present case may represent a truly local disease , which made it suitable for surgical resection using cpb . ctc counts in peripheral blood may also be a useful index to indicate the appropriateness of performing a surgical resection using cpb . the authors declare that they do not have anything to disclose regarding conflict of interest with respect to this article .
tumor resection with cardiopulmonary bypass ( cpb ) remains controversial in the field of oncology . 
 here , we present a 57-year - old male patient with locally advanced squamous cell carcinoma . the tumor was located in the left hilum and invaded the left atrium . 
 complete resection , left pneumonectomy combined with partial left atrium resection , was achieved using cpb . 
 we evaluated the circulating tumor cell ( ctc ) counts , as a surrogate for micrometastasis , in peripheral blood and the cpb circuit . 
 both ctc counts were 0 , which could indicate local disease without micrometastasis . 
 ctc count may be a useful indicator for tumor resection with cpb in lung cancer .