Outcomes of Resected Lung Cancer Diagnosed Through Screening and Incidental Pulmonary Nodule Programs in a Mississippi Delta Cohort

Abstract

Introduction: Early lung cancer detection programs improve surgical resection rates and survival but may skew toward more indolent cancers.

Methods: Hypothesizing that differences in stage-stratified survival indicate differences in biological aggressiveness and possible length-time and overdiagnosis bias, we assessed a cohort who had curative-intent resection, categorized by diagnostic pathways: screening, incidental pulmonary nodule program, and non-program based. Survival was analyzed using Kaplan-Meier plots, log-rank tests, and Cox regression, comparing aggregate and stage-stratified survival across cohorts with Tukey's method for multiple testing.

Results: Of 1588 patients, 111 patients (7%), 357 patients (22.5%), and 1120 patients (70.5%) were diagnosed through screening, pulmonary nodule, and non-program-based pathways; 0% versus 9% versus 6% were older than 80 years (p = 0.0048); 17%, 23%, and 24% had a Charlson Comorbidity score greater than or equal to 2 (p = 0.0143); 7%, 6%, and 9% had lepidic adenocarcinoma; 26%, 31%, and 34% had poorly or undifferentiated tumors (p = 0.1544); and 93%, 87%, and 77% had clinical stage I (p < 0.0001).Aggregate 5-year survival was 87%, 72%, and 65% (p = 0.0009), including 95%, 74%, and 74% for pathologic stage I. Adjusted pairwise comparisons showed similar survival in screening and nodule program cohorts (p = 0.9905). Nevertheless, differences were significant between screening and non-program-based cohorts (p = 0.0007, adjusted hazard ratio 0.33 [95% confidence interval: 0.18-0.6]) and between nodule and nonprogram cohorts (adjusted hazard ratio 0.77 [95% confidence interval: 0.61-0.99]). Stage I comparisons yielded p = 0.2256, 0.1131, and 0.911. In respective pathways, 0%, 2%, and 2% of patients with stage I disease who were older than 80 years had a Charlson score greater than or equal to 2 (p = 0.3849).

Conclusions: Neither length-time nor overdiagnosis bias was evident in NSCLC diagnosed through screening or incidental pulmonary nodule programs.

Keywords: Early detection; Length-time bias; Overdiagnosis bias; Survival.