Abstract
BACKGROUND: Lung cancer, once rare, has evolved into the global leading cause of cancer-related mortality, primarily driven by widespread cigarette smoking in the 20th century. This study explores the historical trends of lung cancer incidence in Denmark over four decades, emphasizing the impact of smoking prevalence, age, and gender on the observed patterns. MATERIALS AND METHODS: Drawing upon data from the Danish National Patient Register and information on smoking habits provided by the Danish Health Authority, this study investigates lung cancer incidence rates, demographic shifts, and smoking prevalence from 1980 to 2022. RESULTS: Smoking prevalence exhibited a consistent decline in males from 1950 to 2022, whereas female smoking prevalence maintained a stable level from 1950 to 1987, followed by a subsequent decline from 1987 to 2022. A peak in lung cancer crude incidence rates was identified during 2014-2017, with no significant difference observed before and after this period. Over the period, the gender distribution transitioned from a male majority to an equal male-female ratio, and age-specific disparities indicated declines in patients aged 50-59 and increases in those above 80 years. INTERPRETATION: The certainty of a decline in lung cancer incidence in the coming years remains unclear. Based on smoking prevalence, it might still be a decade away. To ensure a sustained decline in lung cancer incidence, targeted interventions are imperative, including customized smoking cessation programs that could be designed favorably for females. Given the modest decline in smoking prevalence over the last decade, legislation aimed at discouraging young individuals from smoking is pivotal. As of now, these efforts have not been implemented in Denmark.