P2.16-25 Lower Hiliar Lymph Node Upstaging in Early NSCLC Vats Surgery is Related to Tumor Location and Does Not Afect Survival

Abstract

Nodal upstaging after early stage lung cancer surgery is not only inevitable, but it is also considered a quality marker for surgical lymphadenectomy. Underdiagnosis of pN1 has important significance and leads to undertreatment. Lymphadenectomy has been questioned in video thoracoscopic surgery (VATS) since its description. Recently some authors published lower pN1 upstaging incidence after VATS resection compared to open thoracotomy. We want to evaluate the rate of upstaging in our centre after starting a VATS program. All patient who required an anatomical resection for non-small cell lung cancer (NSCL) in our department have been retrospectively reviewed. Patients were divided in two groups in relation of the performed surgical approach, thoracotomy (THO) and VATS. Both groups were compared in terms of gender, age, smoking history, comorbidities, lung function, histology, clinical stage and tumour location. Rate of hilar lymph node upstaging (pN1) and mediastinal lymph node upstaging (pN2) were compared between both groups. Univariate and multivariate analysis was performed to identify independent risk factors for pN1 upstaging. Overall survival was compared between both techniques in pN0 patients. Between January 2011 and October 2017, 1.081 lung resections were carried out in our centre. 323 of those were anatomical resections for early stage (≤ IIB) non-small cell lung cancer (NSCLC). There were no differences among groups except for FEV1, previous history of Diabetes Mellitus, tumour size and location (p<0.05). pN1 ratio was 20,5% in THO vs. 8,6% in VATS (p < 0,05) when performed accesses was compared. No differences were observed regarding pN2 upstaging (6% in THO and 6,5% in VATS; p>0,05). Only gender and centrality were identified as independent risk factors for hiliar lymph node upstaging in a multivariate analysis. For those patient with no upstaging (pN0) there were no survival differences comparing open and VATS approaches. In our series pN1 upstaging is less frequent in VATS than in open surgery. When analysed, tumour centrality has shown to be an independent risk factor for hilar upstaging. Additionally central tumours were much more prevalent in open surgery group. In conclusion, lower incidence of unnoticed pN1 in VATS surgery could be related to a selection bias, because thoracotomy was preferred when tumour considered central. Furthermore, the fact that no differences on survival in pN0 patients were detected suggests that no patients have been underdiagnosed and in consequence undertreated.