Lung cancer survival trends and prognostic factors: A 26-year population-based study in Girona Province, Spain

Abstract

Background

Lung cancer (LC) is Europe’s primary cause of cancer-related mortality largely due to its historically low survival rates. The aim of this study was to analyze 26-year survival trends in the province of Girona, Spain, and to identify key prognostic factors.

Methods

Population-based study of LC cases collected between 1994 and 2019, with follow-up until December 31, 2021. Variables included date of diagnosis, sex, age, histology, and tumor stage (the latter since 2010). Diagnosis dates were categorized into three periods (1994–2002, 2003–2011, and 2012–2019). Multivariate flexible parametric models, incorporating age as a non-linear, time-varying covariate, were used to analyze net survival (NS) and trends. Annual absolute change in survival (AAC_S) was calculated using 3-year NS.

Results

The analysis of 9,113 LC cases showed a NS improvement between the first and last period (7.1 months (95 %CI: 6.5;7.6) to 8.5 months (95 %CI: 7.9;9.1)). Squamous cell carcinoma (NSC-SCC) showed the greatest improvement with an AAC_S of 0.32 % (95 % CI: 0.21; 0.43), while survival for non-small cell lung cancer not otherwise specified declined (AAC_S of −0.19 % (95 %CI: −0.26; −0.12)). Prognostic analysis of the 3,642 cases (2010–2019) indicated a lower LC death risk for adenocarcinoma and NSC-SCC compared to LC not otherwise specified (HR 0.52 and 0.62, respectively). Increasing tumor stage correlated with higher LC mortality risk (1.8-, 4.0-, and 10.1-fold increase for stage II, III, and IV, respectively, compared to stage I).

Conclusions

LC survival has notably improved, particularly for NSC-SCC. Survival is influenced by sex, age, date of diagnosis, tumor histology and especially by stage, underscoring comprehensive data collection’s importance.