Lung Cancer Cheat Sheet by kissmekate

Risk Factors

• Cigarette smoking (>85% of patients) with a linear relati­onship between pack-years and risk. Adenoc­arc­inoma has the lowest associ­ation with lung cancer. Passive smoke, redone (high levels in baseme­nts), and COPD (indep­endent risk factor even after smoking is taken out). Asbestos (common in shipbu­ilding and constr­uction, car mechanics, and painting profes­sions) and smoking synerg­ist­ically increase risk of lung cancer.

Consti­tut­ional Symptoms

• Anorexia, weight loss, and weakness. Usually associated with advanced disease.

Prognosis

• In SCLC, 5-year survival is 10-13% for limited disease and 1-2% for extensive disease. 85% of SCLC have extensive disease at time of presen­tation. Overall 5-year survival for lung cancer is 14%.

Malignant Pleural Effusion

Occurs in 10-15% of patients. Prognosis is very poor and equivalent to distant metast­ases.

Features of SCLC

• Accounts for 10-15% of cases.
• Central, tend to narrow bronchi by extrinsic compre­ssion, and widespread metastases are common (50-75% of patients at presen­tat­ion). • Associated with Cushing syndrome, SIADH, and Lamber­t-Eaton syndrome.

Diagnosis

Flexible bronch­oscopy for central lesions, transt­horacic needle biopsy, PET scan.

Indica­tions of Benign Nodule

Younger age (50% chance of malignancy if patient is >50), nonsmoker, smaller size (<1cm), smooth­/di­screte borders, dense, central calcif­ication (eccentric asymmetric calcif­ication indicates malign­ancy), no change in size.

Interm­ediate Probab­ility

<1cm: serial CTs.

High Probab­ility

Excision

Phrenic Nerve Palsy

• Occurs in 1% of patients: destru­ction of phrenic nerve by tumor, as the phrenic nerve courses through the medias­tinum to innervate the diaphragm. Results in hemidi­aph­rag­matic paralysis.

Horner's Syndrome

• Due to invasion of cervical sympat­hetic chain by an apical tumor.
• Symptoms include unilateral facial anhidr­osis, ptosis, and miosis.

Parane­opl­astic Syndromes

• SIADH in SCLC (10%).
• Ectopic ACTH secretion in small cell carcinoma. PTH-like hormone secretion is squamous cell carcinoma (const­ipa­tion, thirst, anorexia).
• Hypert­rophic pulmonary osteoa­rth­ropathy in adenoc­arc­inoma and squamous cell carcinoma, associated with severe long bone pain.
• Eaton-­Lambert Syndrome most common in SCLC and looks like myasthenia gravis (proximal muscle weakne­ss/­fat­iga­blity, diminished deep tendon reflexes, parest­hes­ias), digital clubbing.

Treatment of SCLC

For limited disease, combo chemor­adi­ation therapy used initially. For extensive disease, chemot­herapy alone as the initial treatment. If the patient responds, prophy­lactic radiation decreases incidence of brain metastases and prolongs survival. Usually unrese­ctable.

CT Scan

With IV contrast. Very useful for standing and accurate in revealing LAD in medias­tinum. Can demons­trate extent of local and distant metast­asis.

Bronch­oscopy

Can only be inserted as far as secondary branches of bronchial tree. Useful for diagnosing central visualized tumors but not peripheral lesions. The larger and more central a lesion, the higher the diagnostic yield. For visible tumors, bronch­oscopy is diagnostic in >90% of cases.

Transt­horacic Needle Biopsy

Highly accurate and useful for diagnosing peripheral lesions as well. Under fluoro­scopic or CT guidance. Invasive procedure only used in selected patients.

Clinical Presen­tation

Usually asympt­omatic. If symptoms are present, usually due to compre­ssion or invasion. Cough from compre­ssion of trachea or bronchi, sometimes with hemoptysis. Chest pain, dyspnea, post obstru­ctive pneumonia, dysphasia (esoph­ageal compre­ssion), SVC syndrome, hoarseness (compr­ession of recurrent laryngeal), Horner's (compr­ession of sympat­hetic ganglia), diaphragm paralysis (compr­ession of phrenic).

Diagnosis

CT is test of choice. Usually discovered incide­ntally on CXR.