non-small cell lung cancer

non-small cell lung cancer
Name	Non-small cell lung cancer
Field	Oncology, Pulmonology, Pathology
Symptoms	Cough, hemoptysis, dyspnea, weight loss, chest pain
Complications	Metastasis, respiratory failure, paraneoplastic syndromes
Onset	Adult, peak incidence in older adults
Causes	Tobacco smoke, occupational exposures, environmental carcinogens
Risks	Smoking, radon, asbestos, family history
Diagnosis	Imaging, biopsy, molecular testing
Treatment	Surgery, radiotherapy, chemotherapy, targeted therapy, immunotherapy
Prognosis	Variable; stage-dependent

non-small cell lung cancer is a heterogeneous group of malignant epithelial tumors of the lung that excludes small cell histology and accounts for the majority of primary pulmonary cancers. It most commonly presents in older adults with a smoking history and is subclassified into major histologic types that drive staging, management, and molecular testing. Contemporary care integrates surgery, radiotherapy, systemic cytotoxic therapy, targeted agents, and immune checkpoint inhibitors guided by clinicopathologic and genomic factors.

Signs and symptoms

Common presentations include persistent cough, hemoptysis, dyspnea, and unexplained weight loss observed in many patients referred from Royal Marsden Hospital-style multidisciplinary clinics; these symptoms may prompt imaging at centers like Memorial Sloan Kettering Cancer Center or Mayo Clinic. Chest pain and recurrent pneumonia are frequent referral reasons to Johns Hopkins Hospital or Cleveland Clinic thoracic teams, while fatigue and anorexia lead to evaluation at institutions such as Massachusetts General Hospital and Charité – Universitätsmedizin Berlin. Paraneoplastic phenomena—such as hypertrophic pulmonary osteoarthropathy or hypercalcemia—prompt consultation with specialists affiliated with UCSF Medical Center or Peter MacCallum Cancer Centre. Advanced disease produces neurologic deficits from brain metastases and bone pain from osseous involvement seen on scans performed at centers like Guy's Hospital and Royal Brompton Hospital.

Causes and risk factors

Tobacco smoking is the predominant etiologic factor identified by epidemiologic studies from institutions like American Cancer Society and World Health Organization, with dose–response relationships reported in cohorts from Framingham Heart Study-style populations. Occupational exposures linked to increased risk include asbestos, diesel exhaust, and silica described in reports by International Agency for Research on Cancer and occupational clinics at University College London Hospitals. Radon exposure, air pollution episodes studied by groups at Harvard T.H. Chan School of Public Health and Imperial College London, and secondhand smoke reported by Centers for Disease Control and Prevention also contribute. Germline and somatic genetic predispositions—such as EGFR, KRAS, and ALK alterations—have been characterized in genomic efforts led by The Cancer Genome Atlas and International Cancer Genome Consortium. Age, male sex in some registries like SEER Program datasets, chronic obstructive pulmonary disease cohorts from St. Michael's Hospital, and prior radiation therapy increase susceptibility.

Pathophysiology and classification

Non-small cell lung cancer encompasses histologic types including adenocarcinoma, squamous cell carcinoma, and large cell carcinoma as defined by the World Health Organization classification used in pathology services at institutions such as Royal College of Pathologists and College of American Pathologists. Molecular subsets driven by activating mutations (EGFR, BRAF), gene fusions (ALK, ROS1, RET), and amplifications (MET, HER2) are described in publications from Johns Hopkins University and Dana-Farber Cancer Institute. Tumorigenesis involves stepwise genetic and epigenetic changes influenced by carcinogens characterized in studies from National Cancer Institute and environmental research at Scripps Research. The tumor microenvironment, including tumor-infiltrating lymphocytes and PD-L1 expression, informs immunotherapy decisions based on assays developed with collaborators at F. Hoffmann-La Roche and AstraZeneca-sponsored trials.

Diagnosis

Initial evaluation often includes chest radiography and computed tomography performed at radiology departments in hospitals like Mount Sinai Hospital and Karolinska University Hospital. Tissue diagnosis via bronchoscopy, CT-guided percutaneous biopsy, or surgical resection with pathology review at centers such as St. Jude Children's Research Hospital-associated labs establishes histology and enables immunohistochemistry and molecular testing per guidelines from National Comprehensive Cancer Network and European Society for Medical Oncology. Positron emission tomography combined with CT reviewed by nuclear medicine teams at Paul Scherrer Institute aids in staging, while MRI of the brain—routinely used at Royal Marsden Hospital and Princess Margaret Cancer Centre—detects intracranial disease. Liquid biopsy assays developed with input from Guardant Health and research groups at Broad Institute can identify actionable circulating tumor DNA in selected cases.

Staging

Staging follows the tumor-node-metastasis (TNM) system promulgated by the Union for International Cancer Control and the American Joint Committee on Cancer; staging workflows mirror protocols used at tertiary centers such as MD Anderson Cancer Center and Vall d'Hebron University Hospital. Clinical staging integrates CT, PET-CT, and invasive mediastinal staging with endobronchial ultrasound performed in services at Royal Papworth Hospital and Hospital Clínic de Barcelona. Pathologic staging after resection refines prognosis and adjuvant therapy decisions in trials run by cooperative groups like European Organisation for Research and Treatment of Cancer and National Surgical Adjuvant Breast and Bowel Project-style networks.

Treatment

Early-stage disease is managed with anatomic resection and systematic lymphadenectomy at surgical units in centers such as St. Bartholomew's Hospital and University of Texas Southwestern Medical Center, with stereotactic body radiotherapy offered by departments at German Cancer Research Center for inoperable patients. Locally advanced tumors receive multimodal therapy combining chemoradiation and consolidation immunotherapy following pivotal trials conducted by groups including RTOG and EORTC. Advanced and metastatic disease treatment is personalized based on actionable alterations—EGFR tyrosine kinase inhibitors from companies like AstraZeneca and Roche/Genentech, ALK inhibitors developed by Novartis and Pfizer, and ROS1/RET-targeted agents—alongside PD-1/PD-L1 immune checkpoint inhibitors tested in trials at Memorial Sloan Kettering Cancer Center and Dana-Farber Cancer Institute. Palliative care integration, as advocated by World Health Organization and specialist services at Mayo Clinic, addresses symptoms and quality of life.

Prognosis and epidemiology

Prognosis depends on stage at diagnosis, molecular profile, performance status, and access to specialized care seen across registries from Surveillance, Epidemiology, and End Results Program and international cohorts compiled by Global Burden of Disease Study. Five-year survival varies widely between early resectable disease reported in datasets from SEER Program and metastatic cohorts from clinical trials at Royal Marsden Hospital and Memorial Sloan Kettering Cancer Center. Incidence and mortality trends have shifted with smoking prevalence changes documented by the World Health Organization and national agencies like Public Health England, while screening programs using low-dose CT led by initiatives at National Lung Screening Trial and NELSON trial centers have impacted stage distribution and outcomes. Advances in targeted therapy and immunotherapy from research consortia including The Cancer Genome Atlas and pharmaceutical collaborations continue to modify survival trajectories.

Category:Lung cancer