According to a study published in the journal Chest, patients who have surgery for stage IA or stage IB non-small cell lung cancer (NSCLC) survive longer if they have a greater number of lymph nodes examined during surgery.
Lung cancer remains the leading cause of cancer-related deaths in the US. NSCLC is the most common form of the disease. It accounts for approximately 75-80% of all lung cancers. It is named for the type of cell in which the cancer originated. Stage I NSCLC is located in only one lung and has not spread to the adjacent lymph nodes or outside the chest.
The mainstay of treatment for patients diagnosed with a stage I NSCLC has been surgical removal of the cancer. Over 60% of patients who undergo surgical removal of stage I cancers survive without evidence of recurrence within 5 years of treatment. The size and specific location of the cancer may improve or reduce an individual’s chance of cure.
When surgery is conducted in patients with early-stage NSCLC, physicians often remove nearby lymph nodes and have them examined for cancer cells in a laboratory. The number of lymph nodes removed is often based on physician preference.
In order to assess the association between number of lymph nodes examined and postoperative survival, researchers evaluated information from a cancer registry that captures diagnosis and treatment information from several large areas of the US. Between 1990 and 2000, 16,800 patients with stage I NSCLC were treated with surgery. Among patients who did not receive radiation therapy, survival increased according to the number of lymph nodes examined (up to roughly 16 lymph nodes). There did not appear to be additional survival benefit when more than 16 lymph nodes were examined. Results for patients who had been treated with radiation therapy were similar.
The researchers conclude that patients with early-stage NSCLC survive longer if their surgery includes a more extensive examination of lymph nodes. A possible explanation is that fewer positive nodes are missed when more nodes are examined. The researchers avoid defining an “optimal number”, but suggest examination of between 11 and 16 lymph nodes.
Reference: Ludwig MS, Goodman M et al. Postoperative survival and the number of lymph nodes sampled during resection of node-negative non-small cell lung cancer. Chest. 2005;128:1545-1550.
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