Chronic Cough Due to Lung Tumors: Clinical Features of Cancer as a Cause of Cough
Smoking tobacco causes 90% of primary lung cancers. Thus, heavy cigarette smokers who have a new onset of cough, a change in the characteristics of a preexisting cough, and the presence of hemoptysis (usually a small volume, often only streaks) should promote consideration of cancer as the cause of cough. Among other important points in a person’s medical history that lead to a higher index of suspicion for primary lung cancer are passive cigarette smoke exposure; exposure to asbestos, radon, and selected other carcinogens; COPD; and a family history of lung cancer. A personal history of cancer in another body site raises the possibility of metastatic cancer involving the lung.
Cough is present in > 65% of patients at the time lung cancer is diagnosed, and productive cough is present in > 25% of patients. While cough as a presenting symptom of lung cancer is common, many studies have shown that lung cancer is the cause of chronic cough in < 2% of all patients who present with a chronic cough. Normal chest radiograph findings markedly reduce, but do not eliminate, the likelihood that cough is due to a neo-plasm. Conversely, abnormalities on the chest radiograph that are typical for a neoplasm should make the clinician place cancer at the top of the list as a cause for cough, Dyspnea often accompanies the cough caused by a cancer in the airway, regardless of whether the tumor is a primary lung cancer or a metastasis to the bronchus from another site. Intraluminal tumor involvement, particularly if it is in the trachea or a mainstem bronchus, will stimulate cough receptors and also obstruct airflow to produce the sensation of dyspnea. Extraluminal compression of a large airway is more likely to cause dyspnea without associated cough, but cough is not infrequent in this setting. Obstruction of the airway may lead to postobstructive pneumonia, which may accentuate the cough. Specific, tumor-related complications, such as massive hemoptysis and tracheoesophageal fistula, may also accentuate cough and be amenable to problem-directed treatment approaches. Additionally, comor-bid diseases such as obstructive chronic bronchitis, not just the tumor itself, may be independent or contributing causes to cough. Treatment that is directed at the comorbid process may ameliorate the complaint of cough.
Category: Respiratory Symptoms
Tags: ablative methods, antitussives, brachytherapy, bronchoscopy, chemotherapy, electrocautery, endobronchial treatment, laser, lung cancer, metastatic carcinoma (to lungs), radiation therapy, stents, Surgery