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 (FDG-PET/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 I NSCLC 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.
Keywords: Early-stage NSCLC; Nodal upstaging; Non-small cell lung cancer; Systematic lymph node dissection; VATS; Video-assisted thoracoscopic surgery.