Lung Tumors
Pulmonary and Critical Care Medicine · Lung Tumors 🎯 Practice these cards
A pulmonary nodule is a radiographic opacity up to ____ cm in diameter; a focal opacity larger than this is a lung ____ and is presumed ____ until proved otherwise.
A pulmonary nodule is a small, rounded radiographic opacity up to 3 cm in diameter surrounded by normal aerated lung; nodules are asymptomatic by definition. A focal pulmonary opacity larger than 3 cm is a lung mass and is presumed malignant until proved otherwise.
Per Fleischner 2017, a solitary solid nodule <6 mm requires ____; a 6–8 mm nodule gets CT at ____ months; and a nodule >8 mm warrants CT at 3 months, ____, or tissue sampling.
Fleischner Society 2017 for a single solid nodule: <6 mm — no follow-up regardless of risk; 6–8 mm — CT at 6–12 months, then consider (low risk) or perform (high risk) CT at 18–24 months; >8 mm — consider CT at 3 months, PET/CT, or tissue sampling.
The first step for a solid nodule >8 mm is estimating the ____ using age, smoking history, size, location, and border morphology (e.g., the ____ calculator); if probability is moderate, the next step is ____.
The first step in evaluating a solid pulmonary nodule larger than 8 mm is estimating the pretest probability of malignancy using age, smoking history, nodule size, location within the lung, and border morphology (spiculated/lobulated), e.g., with the validated Brock/PanCan calculator. High probability → staging PET and definitive therapy; moderate probability → PET, with CT surveillance if negative and tissue sampling if avid.
Subsolid nodules grow very slowly (volume doubling times of ____ days), so surveillance must continue for at least ____ year(s); a pure ground-glass nodule ≥6 mm gets CT at ____ months to confirm persistence, and a new or enlarging ____ component signals invasive transformation.
Subsolid nodules (pure ground glass or part-solid) often represent premalignant or indolent adenocarcinoma-spectrum disease with volume doubling times of 400–800 days, so surveillance must continue for at least 5 years. Fleischner 2017: pure ground-glass nodule ≥6 mm gets CT at 6–12 months to confirm persistence, then CT every 2 years until 5 years; part-solid nodule ≥6 mm gets CT at 3–6 months, then annual CT for 5 years if the solid component stays <6 mm. PET and needle biopsy are unreliable; a new or enlarging solid component signals invasive transformation.
____ is the most common benign lung neoplasm; on imaging it appears as a smooth-bordered nodule that may contain fat, and ____ calcification is a classic benign pattern.
Hamartomas are the most common benign lung neoplasm — rare lesions composed of cartilage, connective tissue, smooth muscle, fat, and respiratory epithelium. On imaging they appear as smooth-bordered nodules that may contain fat; "popcorn" calcification is a classic benign pattern.
USPSTF lung cancer screening: annual ____ for asymptomatic adults aged ____ years with at least a ____-pack-year smoking history who currently smoke or quit within the past ____ years.
The USPSTF gives annual low-dose CT screening a grade B recommendation for asymptomatic adults aged 50–80 years with at least a 20-pack-year smoking history who currently smoke or quit within the past 15 years. Stop screening once a person has not smoked for 15 years, or in anyone with limited life expectancy or who would not undergo curative surgery.
The NLST showed that LDCT screening produced a ____% relative reduction in lung cancer mortality and a ____% reduction in all-cause mortality, although roughly ____% of positive screens were false positives.
The National Lung Screening Trial randomized more than 53,000 high-risk individuals (aged 55–74 with ≥30 pack-years) to three annual screens of LDCT versus chest radiography: LDCT produced a 20% relative reduction in lung cancer mortality and a 6.7% reduction in all-cause mortality, detecting nearly twice as many stage IA cancers — but roughly 96% of positive screens were false positives. The NELSON trial independently confirmed a mortality benefit.
____ accounts for about 80% of lung cancers, with three subtypes: adenocarcinoma, ____ cell, and large cell; ____ accounts for about 15% and is the histology most strongly associated with cigarette smoking.
There are two major classes of lung cancer: non–small cell lung cancer (NSCLC), about 80% of cases, with three subtypes (adenocarcinoma, squamous cell, and large cell), and small cell lung cancer (SCLC), about 15%, which is the histology most strongly associated with cigarette smoking. The distinction is fundamental because natural history and treatment algorithms differ entirely.
____ is the most common NSCLC subtype, typically peripheral and predominant in nonsmokers; ____ carcinoma arises in the central airways of smokers and presents with hemoptysis; ____ cell carcinoma presents as a large peripheral mass with prominent necrosis.
Adenocarcinoma is the most common NSCLC subtype, arises peripherally, and is the diagnosis behind nearly all lung cancers in nonsmokers. Squamous cell carcinoma is strongly linked to smoking, originates in the central airways, and presents with cough and hemoptysis (keratinization and intercellular bridges on histology). Large cell carcinoma (<10% of cases) is undifferentiated and presents as a large peripheral mass with prominent necrosis.
SCLC typically presents as a large ____ mass; its classic paraneoplastic syndromes include ____ (hyponatremia), Cushing syndrome from ectopic ____ secretion, and Eaton-Lambert myasthenic syndrome.
SCLC typically grows adjacent to central airways and commonly shows a large mediastinal mass incorporating lymph nodes with extensive metastases at diagnosis. Paraneoplastic syndromes are most common with SCLC: SIADH causing hyponatremia, Cushing syndrome from ectopic ACTH secretion, and the Eaton-Lambert myasthenic syndrome (anti–voltage-gated calcium channel antibodies). Nearly all SCLCs harbor TP53 and RB1 inactivation and are neuroendocrine (CD56, synaptophysin, chromogranin positive).
Limited-stage SCLC is confined to one ____ and ipsilateral ____ lymph nodes — disease encompassable within a tolerable ____ port; ____% of SCLC patients present with extensive disease.
NSCLC is staged with the TNM system, while SCLC is generally staged as limited or extensive disease. Limited disease is confined to one hemithorax and ipsilateral supraclavicular lymph nodes — that is, disease that can be encompassed within a tolerable radiation port; any disease beyond those boundaries is extensive stage. Sixty to seventy percent of SCLC patients present with extensive disease.
PET false negatives occur for cancers smaller than ____ cm and slow-growing tumors such as ____; false-positive uptake occurs with infection and ____ disease, so PET findings always require ____ confirmation.
PET false-negative results occur for cancers smaller than 1 cm and for slow-growing tumors such as carcinoids and well-differentiated adenocarcinomas; nodules 8 mm or smaller and subsolid nodules are not reliably characterized by PET. False-positive uptake occurs with infection and granulomatous disease. The definitive diagnosis of lung cancer requires tissue histopathology — PET alone should never establish a diagnosis.
Carcinoid tumors account for ____% of lung cancers, are ____-grade neuroendocrine neoplasms for which smoking is ____ a risk factor, and are often cured by ____, with 10-year survival rates higher than 90%.
Carcinoid tumors are low-grade neuroendocrine neoplasms accounting for 1%–2% of all lung cancers; smoking is not a risk factor. They arise in the proximal airways, causing cough, dyspnea, monophonic wheezing, and recurrent pneumonia in the same pulmonary segment; misdiagnosis as asthma or pneumonia commonly delays diagnosis. Surgical resection is often curative, with 10-year survival rates higher than 90%.
Mesothelioma is caused by ____ exposure, with a latency of ____ years; pleural fluid ____ has sensitivity <50%, so diagnosis requires pleural biopsy (____ has >90% sensitivity), and median survival is ____ months.
Malignant pleural mesothelioma is causally associated with inhalational asbestos exposure, with a latency of 20–40 years; because of asbestos control, U.S. incidence has declined since 2000. Pleural fluid cytology has sensitivity <50% and cannot make the diagnosis — pleural biopsy is required, and medical or surgical thoracoscopy has >90% sensitivity. Prognosis is poor, with median survival of 6–9 months.
Anterior mediastinal masses are the "terrible T's": thymoma, ____, lymphoma, and ____; middle mediastinal masses are most often ____; posterior mediastinal masses are most often ____ tumors.
Anterior mediastinal masses are the "terrible T's": thymoma, teratoma/germ cell tumor, "terrible" lymphoma, and thyroid; thymic lesions are the most common and are associated with myasthenia gravis and pure red cell aplasia. Middle mediastinal masses are most often lymphadenopathy (lymphoma, sarcoidosis, metastatic disease). Posterior mediastinal masses are most often neurogenic tumors.
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