Visceral pleural invasion (VPI) may impact non-small cell lung cancer (NSCLC) survival. However, previous studies are mixed as to whether VPI is an independent prognostic factor in early-stage cancers and whether its effect is size dependent. In the current American Joint Committee on Cancer (AJCC) staging system, VPI leads to upstaging of cancers < 3 cm but not of those 3 to 7 cm in size.
Using the Surveillance, Epidemiology, and End Results (SEER) registry, we identified 16,315 patients with stage I-II NSCLC treated with lobectomy. We used the Kaplan-Meier method and Cox regression to assess the association of VPI with lung cancer-specific (primary outcome) and overall survival. Based on these results, we created a revised VPI staging classification.
Overall, 3,389 patients (21%) had VPI. Kaplan-Meier analysis stratified by tumor size showed worse cancer-specific survival in patients with VPI (P < .0001). VPI was independently associated with decreased lung cancer-specific survival (hazard ratio, 1.38; 95% CI, 1.29-1.47) after controlling for tumor size and other confounders; this effect was not size dependent. In our revised classification, tumors < 7 cm with VPI were upstaged to the next T category.
VPI is a prevalent finding associated with worse prognosis in early-stage lung cancer, even among patients with tumors > 3 cm, a factor not captured in the current staging system. Patients with VPI may be considered candidates for more aggressive treatment.