Video-assisted thoracic surgery systematic mediastinal nodal dissection and stage migration: impact on clinical pathway.

OBJECTIVES: The aim of this study is to investigate the role of routine systematic mediastinal nodal dissection (SND) performed during video-assisted thoracic surgery (VATS) major pulmonary resections (VMPRs) as a staging strategy for non-small-cell lung cancer (NSCLC), compared with preoperative staging by conventional positron emission tomography (PET) and computed tomography (CT) imaging.

METHODS: All patients suspected of having early lung cancer (T1-2, N0-1 and M0) were staged preoperatively by CT/PET. During VMPR, all lymph nodes on the right side at stations 2-4, 7, 8, 9, 10 and 11 and on the left stations 4-6, 7, 8, 9, 10, 11 and 3 when indicated were dissected en bloc. Histology was provided on the paraffin-embedded nodes, and patients staged accordingly. Preoperative and postoperative stagings were compared. Stage migration and impact on clinical pathway were noted. Stage IIa and higher were referred for adjuvant chemotherapy.

RESULTS: Between April 2007 and January 2011, 106 consecutive patients with suspected primary NSCLC proceeded to VMPR+SND. Histology confirmed NSCLC in 96 patients. Forty-five were men and 51 women. Median age was 68.6 (range 42.8-84.7) years. As many as 91 (94.8%) patients underwent lobectomy, three (3.1%) bilobectomy and two (2.1%) pneumonectomy. PET accurately correlated with SND histological diagnosis in 42 (43.8%) patients. The unexpected N2 disease in cN0-1 was 9/86 (10.5%). SND resulted in 25 stage migrations, upstaged 16 (16.6%) and down-staged nine (9.4%) patients. All upstagings were adenocarcinoma. Four (4.2%) PET-negative patients had multi-station N2 disease. SND resulted in changing the clinical pathway for 19 (20%) patients. Fourteen (14.6%) patients upstaged to qualify for chemotherapy, and 5/9 (5.2%) down-staged patients were saved the chemotherapy. There was no morbidity or mortality attributable to this added procedure.

CONCLUSIONS: SND during VMPR is safe and should be routinely performed even when nodal metastases is considered unlikely. VATS-SND is more accurate than PET in staging the mediastinum for NSCLC. PET sensitivity is significantly reduced in adenocarcinoma and might result in stage migration. Adjuvant multidisciplinary treatment should be based on SND staging.