Nonexamination of lymph nodes and survival after resection of non-small cell lung cancer.

BACKGROUND

Nonexamination of lymph nodes is an extreme example of the variability of pathologic nodal staging of non-small cell lung cancer. We compared the prevalence, characteristics, and survival of patients without lymph nodes (pNX) to patients with documented pathologic N0 and pathologic N1 non-small cell lung cancer.

METHODS

A retrospective analysis was done of non-small cell lung cancer resections in the US Surveillance, Epidemiology, and End Results database from 1998 to 2009.

RESULTS

Thirteen percent of all resections (18% of node negative resections) were pNX, including 6% of all node-negative lobar or greater resections and 51% of sublobar resections. Thirty-five percent of pNX resections were lobar or greater compared with 90% of pathologic N0 (p < 0.0001). Advanced age and surgery in rural locations were also significantly associated with pNX resection. The median duration of survival was 3 years in the pNX cohort, 6.4 years in the N0 cohort (p < 0.0001), and 2.8 years in the N1 group, with respective 5-year survival rates of 47%, 67%, and 45% (p < 0.0001). These survival differences remained after adjustment for potentially confounding factors.

CONCLUSIONS

Patients with pNX resections are a high-risk subset, with survival approximating pathologic N1, not N0. They should have further attempts at retrieving lymph nodes for examination or be offered postoperative adjuvant chemotherapy. We predict that treatment modalities that fail to address lymph nodes are likely to yield inferior survival in comparison to surgery with proper lymph node examination. The proportion of pNX lung resections may be a sentinel quality indicator for lung cancer programs.