Snapshot A 69-year-old male with a 50 pack-year smoking history presents to his physician with complaint of worsening cough. He describes frequently coughing up blood in the past few weeks. He has unintentionally lost about 10 pounds of weight in the past month and has felt more fatigued than usual. On physical examination, he has ptosis and a constricted pupil in his left eye. His right eye is normal. A chest radiograph is obtained and is shown in the image. Introduction Overview lung cancer is a malignancy that affects the lung parenchyma or airways most lung cancers can be divided into small cell lung cancer non-small cell lung cancer Epidemiology incidence second most common cancer leading cause of cancer-related death risk factors cigarette smoking login to view 2 more bullets asbestos radon family history of lung cancer Prognosis depends on cancer type and severity Screening performed with a low-dose computerized tomography (CT) scan of the chest indicated in patients 55-80 years of age who have a 30 pack-year smoking history and either of the following login to view 2 more bullets Classification Small Cell Lung Cancer (SCLC) Type Location Associated Findings Histology Small cell (oat cell)lung cancer Central MYC gene amplication May produce adrenocorticotropic hormone (ACTH) leads to Cushing syndrome excessive anti-diuretic hormone (ADH) leads to syndrome of inappropriate ADH (SIADH) presynaptic calcium channel antibodies leads to Lambert Eaton syndrome Small dark blue tumor cells with lack of nucleoli and high nuclear:cytoplasm ratio Positive staining for neuron-specific enolase chromogranin A Non-Small Cell Lung Cancer (NSCLC) Type Location Associated Findings Histology Adenocarcinoma Peripheral Most common cause of lung cancer in non-smokers cause of lung cancer (excluding metastasis) Adenocarcinoma in situ tumor growth along alveolar structures lepidic growth pattern Patients may havehypertrophic osteoarthropathy Common gene mutations include KRAS EGFR ALK Typically mucin positive and has a glandular appearance Large cell carcinoma Peripheral Associated with a poor prognosis Highly associated with smoking Pleomorphic giant cells Squamous cell carcinoma of the lung Central Can arise from the bronchus Keratin pearls Intracellular bridges Bronchial carcinoid tumor Central or peripheral Carcinoid syndrome Better prognosis Neuroendocrine cells Chromogranin A positive Presentation Symptoms cough wheezing unintentional weight loss hemoptysis chest pain dyspnea hoarseness suggests involvement of the recurrent laryngeal nerve Physical exam finger clubbing Imaging Radiography indication initial imaging modality when evaluating a patient with symptoms concerning for lung cancer login to view 1 more bullet Computerized tomography (CT) scan indication perform with low-doses to screen for lung cancer (review "screening" in the introduction) further evaluate pulmonary nodule found on radiography login to view 1 more bullet Studies Laboratory testing complete blood count liver function tests (e.g., alanine aminotransferase, aspartate aminotransferase, and total bilirubin) abnormalities may suggest liver metastasis alkaline phosphatase abnormalities may suggest liver or bone metastasis login to view 1 more bullet calcium abnormalities may suggest bone metastasis or paraneoplastic syndromes Pulmonary function tests Evaluation of an incidental solitary pulmonary nodule introduction benign features login to view 4 more bullets malignant features login to view 2 more bullets solitary pulmonary nodule < 8mm if there are or are not risk factors, one typically does surveillance with a chest CT in a few months depending on the size of the lesion solitary pulmonary nodule > 8mm very low probability of malignancy login to view 1 more bullet low/moderate probability of malignancy login to view 5 more bullets high probability of malignancy login to view 1 more bullet Differential Tuberculosis differentiating factors abnormal quantiferon or purified protein derivative (PPD) test history of ↑ risk of exposure (e.g., household contact with someone with diagnosed tuberculosis or travel to tuberculosis-endemic area) Treatment Small cell lung cancer most cases are non-resectable and thus require chemotherapy (e.g., carboplatin and etoposide) Non-small cell lung cancer treatment includes surgical removal, lymph node sampling or dissection, radiation, and chemotherapy depends on the staging Complications Superior vena cava syndrome Pancoast tumor may cause Horner syndrome Metastasis Pericardial effusion Pleural effusion Paraneoplastic syndromes hypercalcemia of malignancy ectopic secretion of PTH-related protein (PTHrP) Lambert-Eaton syndrome SIADH Cushing syndrome