The clinical manifestations of lung cancer depend on the location and extent of the tumor. In patients who have localized disease, the most common symptoms are related to obstruction of major airways; infiltration of lung parenchyma; and invasion of surrounding structures, including the chest wall, major blood vessels, and viscera.
Cough is a major manifestation of lung cancer and is present in nearly 80% of patients with symptomatic lung cancer. It is important to remember, however, that most lung cancer patients are current or former smokers, and they may have a cough related to chronic irritation of the upper and/or lower airways from cigarette smoke. Therefore, smokers should be asked whether there has been a change in their cough, such as an increase in frequency or severity.
Dyspnea and Hemoptysis
Increasing dyspnea and hemoptysis may be signs of lung cancer, although in the case of hemoptysis, 70% of patients bleed from nonmalignant causes, mostly infection, and more frequently, bronchitis. In patients who present with hemoptysis, are older than 40 years, and have a history of smoking and chronic obstructive pulmonary disease without an abnormality on chest radiographs, lung cancer should be considered in the differential diagnosis.
Postobstructive pneumonia secondary to partial or complete bronchial obstruction occurs relatively frequently in association with lung cancer. It is important to obtain repeated chest radiographs in adults who have been treated for pneumonia to be certain that the radiographic abnormalities have cleared completely.
Lung cancer may spread to the pleural surface or may obstruct segmental or lobar lymphatics, resulting in pleural effusion and increased dyspnea.
Approximately 5% of lung tumors invade the chest wall. The resultant pain is a better predictor of chest wall invasion than are chest CT findings. An individual who complains of persistent chest pain should have chest radiography to exclude the presence of peripheral lung cancer that has invaded the chest wall.
Shoulder and Arm Pain
Apical tumors that infiltrate surrounding structures (also called Pancoast or superior sulcus tumors) produce shoulder and/or arm pain as a result of brachial plexus compression. Tumors in the apical lung segments that involve the superior sulcus of the chest may be difficult to detect on a routine chest radiograph; therefore, a person who complains of persistent shoulder pain, particularly with signs of neurologic involvement, should have a CT scan of the chest to look for an apical tumor. An MRI scan of the chest apex may be beneficial to assess depth and vascular invasion. It is also important to examine the lung apex in bone films obtained to evaluate shoulder pain.
Invasion of the sympathetic ganglion by an apical lung tumor causes Horner's syndrome (ptosis, myosis, and ipsilateral anhidrosis).
Hoarseness secondary to vocal cord paresis or paralysis occurs when tumors and lymph node metastases compress, cause dysfunction in, or invade the recurrent laryngeal nerve. This situation is more common on the left side, where the recurrent laryngeal nerve passes under the aortic arch, but it may also occur with high lesions on the right side of the mediastinum.
Other Symptoms of Tumor Compression
Lung tumors may also cause dysphagia by compression or invasion of the esophagus or may cause superior vena cava syndrome by compression or invasion of this vascular structure.
Some tumors may result in wheezing or stridor secondary to compression or invasion of the trachea and may also cause signs of cardiac tamponade secondary to involvement of the pericardial surface and subsequent accumulation of pericardial fluid.
Signs and Symptoms of Metastatic Disease
Lung cancer can metastasize to multiple sites, most commonly to bone, liver, brain, lungs (contralateral or ipsilateral), and adrenal glands.
A lung cancer patient who has brain metastases may complain of headaches or specific neurologic symptoms, or family members may notice a decrease in the patient's mental acuity. Also, metastatic lung cancer may cause spinal cord compression, resulting in a characteristic sequence of symptoms: pain, followed by motor dysfunction, and then sensory symptoms. The patient may have any or all of these symptoms.
Patients who complain of band-like pain encircling one or both sides of the trunk may have spinal cord compression. In addition, coughing and sneezing may cause significant exacerbation of pain from spinal cord compression.
A bone radiograph and/or a bone scan is warranted in lung cancer patients who complain of persistent pain in the trunk or extremities. If performed in the evaluation of lung cancer, 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) supplants the need for a bone scan in most patients. PET appears to be more sensitive with similar specificity for bone metastases when compared with bone scan. If plain films are normal or equivocal for metastases, CT and/or magnetic resonance imaging (MRI) may be helpful to evaluate suspicious areas. MRI of the spine is the most effective way to evaluate suspected spinal cord compression.
Systemic Paraneoplastic Symptoms
Lung cancer is commonly associated with systemic manifestations, including weight loss (with or without anorexia). In addition, patients frequently complain of fatigue and generalized weakness. SCLC is associated with hormone production, which causes endocrine syndromes in a subset of patients, such as SIADH (syndrome of inappropriate antidiuretic hormone secretion) and via secretion of ACTH (adrenocorticotropic hormone) hypercortisolism.
Specific Neurologic Syndromes
Syndromes such as Lambert-Eaton syndrome (see "Oncologic Emergencies and Paraneoplastic Syndromes" chapter), cortical cerebellar degeneration, and peripheral neuropathy may occur in lung cancer patients but are relatively rare.
Although clubbing may occur in a variety of conditions, it is important for the clinician to evaluate a patient's hands. If clubbing is noted, obtaining a chest radiograph may result in the early diagnosis of lung cancer.
Hypertrophic Pulmonary Osteoarthropathy
A relatively small percentage of patients with lung cancer may present with symptomatic hypertrophic osteoarthropathy. In this syndrome, periosteal inflammation results in pain in affected areas, most commonly the ankles and knees. It is frequently associated with clubbing.
This syndrome is extremely uncommon in patients who have a bronchial or pulmonary carcinoid tumor. Most of these patients are asymptomatic (tumors are found by radiography), and a few have cough from an endobronchial lesion.