Does the number of lymph nodes sampled make a difference?

This study evaluated whether the number of resected lymph nodes is associated with survival rate in patients with Non-Small Cell Lung Cancer (NSCLC).

Lung cancer cells can reach the lymph nodes (small collections of immune cells) around the bronchi (the airway ducts that deliver air to the lungs) and in the area between the lungs and begin to grow inside them. This way cancer cells are more likely to spread to other organs of the body. Choosing the best treatment option is based on whether or not the cancer has spread to the nearby lymph nodes. Examining the lymph nodes status during surgery for lung cancer is an important step in establishing a pathologic stage of the tumor. For instance, during surgery the doctor may assign a pathologic N0 status (no cancer was found in the lymph nodes) or Nx (no lymph node examined). In this situation, patient survival following resection for NSCLC is associated with the number of lymph nodes evaluated during surgery. The optimal number of lymph nodes that should be examined is still uncertain. 

428 patients treated with surgical resection for NSCLC were included in this study. The researchers found that a higher number of lymph nodes removed during surgery is associated with better survival among patients with negative lymph node status. The best results were obtained in patients who underwent surgery for tumors smaller than 3.5 cm and had at least 7 lymph nodes removed. Compared with patients who had less than 7 lymph nodes examined, patients with more than 7 lymph nodes evaluated had better survival and had a decreased risk for cancer recurrence (return of the cancer after treatment). 

In summary, the number of lymph nodes examined during surgery for NSCLC, in relation with tumor size, is strongly associated with patients’ outcomes. According to this study, the surgeon needs to remove at least 7 lymph nodes to avoid a staging error and to identify patients who would need more aggressive treatments.   

Further studies are needed to confirm the significance of lymph node examination on postoperative survival. 

Talk to your doctor about the most appropriate treatment in your situation.