Abstract

A REVIEW ON LUNG CANCER IN NON-SMOKERS: REVIEW OF DISEASE PROGRESSION AND PHARMACOLOGICAL TREATMENT PARADIGMS

Ashika S. S.*, Mrs. Anusha Jasmin R. J., Dr. Kiran K. J., Mr. Shabin, Ms. Amina S. S., Ms. Varsha Johnson, Dr. Prasobh G. R.

Abstract

Lung cancer remains the leading cause of cancer-related mortality worldwide and in the USA, with smoking historically accounting for most cases. However, smoking prevalence has declined significantly, while the proportion of lung cancer in individuals who have never smoked (LCINS) is rising. In 2023, >20,000 lung cancer deaths in the USA were projected in never-smokers, making LCINS the 8th leading cause of cancer death in the USA and 5th globally. LCINS differs clinically and molecularly from smoking-related lung cancer. It occurs predominantly as adenocarcinoma and is more common in women and individuals of Asian ancestry. Genomically, LCINS is enriched for targetable alterations such as EGFR mutations and ALK rearrangements. Key risk factors for LCINS include second-hand smoke, air pollution, radon exposure, occupational carcinogens, chronic respiratory inflammation, hormonal factors, and germline or somatic gene mutations including EGFR, KRAS, ALK, TP53, and others. The main histologic types are non-small cell lung cancer (NSCLC, ∼85%) and small cell lung cancer (SCLC, ∼15%). Diagnosis relies on imaging, sputum cytology, and biopsy with molecular testing. Treatment options include surgery, chemotherapy, radiation, immunotherapy, and targeted therapies directed at specific mutations. Prevention strategies for non-smokers focus on radon testing, avoiding second-hand smoke, reducing air pollution exposure, occupational safety, and healthy lifestyle practices.

Keywords: Lung Cancer in non-smokers (LCINS), Non-small cell lung cancer (NSCLC), Small cell lung cancer (SCLC)