Early Symptoms
Early lung cancer often shows no symptoms. When symptoms do arise, they are typically nonspecific respiratory problems – coughing, shortness of breath, or chest pain – that can differ from person to person. Many individuals experience coughing that either begins suddenly or increases in frequency and intensity. Around 25% of patients cough up blood, ranging from small streaks to larger amounts. Approximately 50% of those diagnosed with lung cancer experience shortness of breath, and 25-50% report persistent chest pain that remains in the same location over time.
Systemic Symptoms
In addition to respiratory symptoms, some people experience systemic symptoms including loss of appetite, weight loss, general weakness, fever, and night sweats.
Location-Specific Symptoms
Certain symptoms can suggest the presence of tumors in specific locations. For example:
- Tumors in the thorax can obstruct the trachea, causing breathing problems.
- Difficulty swallowing may occur when tumors compress the esophagus.
- Hoarseness may be caused by tumors disrupting the larynx's nerves.
- Shoulder pain and destruction of the topmost ribs may be present in tumors at the top of the lung (Pancoast tumors).
- Swollen lymph nodes above the collarbone may indicate tumor spread within the chest.
Paraneoplastic Syndromes
Lung tumors may also cause the release of hormones, leading to a variety of unusual symptoms:
- Hypercalcemia (high blood calcium) can cause nausea, vomiting, abdominal pain, and mental confusion.
- Hypokalemia (low potassium) and hyponatremia (low sodium) are common due to inappropriate hormone secretion.
- Up to 30% of lung cancer patients experience nail clubbing, and up to 10% may have hypertrophic pulmonary osteoarthropathy.
Additionally, paraneoplastic blood clotting, including venous thrombophlebitis and disseminated intravascular coagulation, may occur in some individuals.