Lung cancer is the leading cause of cancer-related death worldwide and in Chile, especially among young women due to increased tobacco consumption. In Chile, the incidence and mortality of this disease have risen in recent years. Most cases are diagnosed at advanced stages, limiting treatment options to palliative care. Aim: characterize adult patients with histologically confirmed lung cancer at the Regional Hospital of Temuco between October 2019 and June 2023, and to analyze factors such as smoking, biomass exposure, symptoms at diagnosis, and molecular mutations. Material and Methods: A cross-sectional study was conducted on adult patients with histologically confirmed lung cancer at the Regional Hospital of Temuco between October 2019 and June 2023. Data was collected on biosociodemographic characteristics, medical history, smoking, biomass exposure, symptoms at diagnosis, performance status, biopsy type, pathological results, and molecular mutation studies. Results: Out of 256 patients diagnosed with lung cancer, 220 met the inclusion criteria for histological confirmation. 55.3% were male, with a mean age of 68 ± 9.5 years. 67.7% had a history of smoking, and 30.1% were exposed to biomass. 98.6% presented symptoms at diagnosis, with cough being the most common. The majority (81.9%) were diagnosed at advanced stages (III-IV). 63.9% of diagnoses were adenocarcinomas, with EGFR mutations found in 13.6% and ALK mutations in 2.1%. PDL-1 expression was detected in 18.8% of cases. Significant associations were found between EGFR and ALK mutations, which were more predominant in non-smokers, and between PDL-1 expression and biomass exposure. Conclusions: Lung cancer primarily affects men, with a mean age at diagnosis similar to that reported in other studies. Smoking remains the main risk factor, while biomass exposure also contributes to risk in the region. Most patients were diagnosed at advanced stages of the disease. Adenocarcinoma was the most frequent subtype, with EGFR and ALK mutations found at lower rates than in other national studies. PDL-1 expression showed a significant association with biomass exposure and advanced stages of the disease.