A standardized technique of systematic mediastinal lymph node dissection by video-assisted thoracoscopic surgery (VATS) leads to a high rate of nodal upstaging in early-stage non-small cell lung cancer

Background A substantial part of the oncologic surgical procedure in non-small cell lung cancer (NSCLC) is systematic lymph node dissection (sLND). However, controversies still exist regarding the quality of minimally invasive (video-assisted thoracoscopic surgery, VATS) sLND in oncologic resections. The rate of stage migration from clinical to pathological N-status has been discussed as one parameter for the quality of sLND. Methods Between March 2011 and May 2014, seventy-seven patients (62 male, 15 female) were scheduled for anatomical lung resection and sLND by VATS for clinical stage I (UICC 7th edition) NSCLC. Preoperative staging was performed by [18F]-fluorodesoxyglucose positron emission tomography with computed tomography (FDGPET/CT). Patient data were retrospectively analyzed with regard to divergence in clinical and pathological N-factor. FDG-PET/CTs of patients with lymph node (LN) upstaging after VATS resections were blindly re-evaluated by an experienced radiologist. Results In FDG-PET/CT, preoperative tumor stage was cT1N0M0 in 41 (53.2%) and cT2aN0M0 in 28 (36.4%) patients. In six (7.8 %) patients the primary tumor was not suspicious for malignancy, and in two (2.6 %) patients the tumor was not evaluable due to prior wedge resection before FDG-PET/CT. Thirty-one (40.3 %) left-sided and 46 (59.7 %) right-sided pulmonary resections with sLND were performed; 19.57 +/- 0.99 LNs were dissected. In 13 (16.9 %) patients a nodal stage migration from preoperative clinical to postoperative pathological N-stage was observed [cN0 to pN1 in 9 (11.7 %) and cN0 to pN2 in 4 (5.2 %) cases]. In correlation to the clinical T-factor, the rate of N-factor upstaging for cT1 was 12.2 % and for cT2a was 28.6 %, respectively. In 50 % of the patients with postoperative nodal staging shift, no changes were observed on re-evaluation of the preoperative FDG-PET/CT. Conclusion In this series of clinical stage INSCLC patients, the rate of nodal stage migration after sLND by VATS is higher than previously reported. Prospective randomized controlled trials are needed to prove the oncologic quality of a sLND by VATS versus standard open approach.