Improved staging using intraoperative ultrasound for mediastinal lymphadenectomy in non-small lung cancer surgery

Extent of lymph node involvement in patients with non-small cell lung cancer (NSCLC) is the cornerstone of staging and influences both multimodality treatment and final outcome. The aim of this study was to investigate accuracy and characteristics of intraoperative ultrasound guided systematic mediastinal nodal dissection in patients with resected NSCLC.

From January 2008 to June 2013, 244 patients undergoing intraoperative surgical staging after radical surgery for NSCLC were included in prospective study. The patients were divided in two groups according to systematic mediastinal nodal dissection: 124 patients in intraoperative ultrasound nodal dissection guided group and 120 in standard nodal dissection group. The lymph nodes were mapped by their number and station and histopathologic evaluation was performed.

Operating time was prolonged for 10 min in patients with ultrasound guided mediastinal nodal dissection, but number and stations of evaluated lymph nodes were significantly higher (p < 0.001) in the same group. Skip nodal metastases were found in 24% of patients without N1 nodal involvement. Twelve (10%) patients were upstaged using US guided mediastinal lymphadenectomy. In US guided group 5-year survival rate was 59% and in the group of standard systematic mediastinal lymphadenectomy 43% (p = 0.001) Standard staging system seemed to be improved in ultrasound guided mediastinal lymphadenectomy patients. Complication rate showed no difference between analyzed groups.

Higher number and location of analyzed mediastinal nodal stations in patients with resected NSCLC using ultrasound is suggested to be of great oncological significance. Our results indicate that intraoperative ultrasound may have important staging implications.