Modified staging system for pulmonary carcinoids on the basis of lung cancer TNM system

Abstract

Background: Pulmonary carcinoids are being staged along the lines of lung cancer American Joint Committee on Cancer (AJCC) staging system. The current study evaluated the prognostic value of a modified staging system for patients with pulmonary carcinoid.

Patients and methods: Surveillance, Epidemiology and End Results (SEER) database (2004-2014) was searched through SEER*Stat program. Through recursive partitioning analysis and subsequent decision tree formation, suggested stages were constructed. Overall survival analyses were performed through Kaplan-Meier analysis. The cancer-specific Cox regression hazard (adjusted for age, gender, race, sub-site and surgery) was calculated and pairwise comparisons of hazard ratios were conducted.

Results: A total of 6395 pulmonary carcinoid patients were recruited in the period from 2004-2014. Pairwise hazard ratio comparisons among different AJCC 8th stages were conducted and all comparisons were non-significant except for stage IIB vs. stage IIIA and stage IIIA vs. stage IIIB. Pairwise hazard ratio comparisons among different modified staging system stages were conducted and all comparisons were significant except for stage III vs. stage IV. C-statistic (using death from pulmonary carcinoid as the dependent variable) for AJCC 8th staging system was: 0.794 (SE 0.013; 95% CI 0.769-0.818); for AJCC 7th staging system was: 0.789 (SE 0.013; 95% CI 0.764-0.815), while c-statistic for the modified staging system was: 0.802 (SE 0.012; 95% CI 0.778-0.827).

Conclusion: The proposed modified staging system provided a simpler yet prognostically more relevant classification of pulmonary carcinoids compared to AJCC staging systems (both 7th and 8th editions).

Keywords: Carcinoid; NET; Prognosis; Staging.