Lung cancer begins in the lungs with the uncontrolled growth of abnormal cells that form tumors, interfering with normal lung function. How lung cancer presents can differ significantly. Symptoms often vary depending on the tumor’s location, size, and whether it has spread. In its early stages, lung cancer may not cause noticeable symptoms, making early detection challenging. Recognizing its diverse appearances is important for seeking timely medical attention.
Respiratory Manifestations
Lung cancer often presents with symptoms directly affecting the respiratory system. A persistent cough that does not improve or worsens over time is a common sign, sometimes producing rust-colored sputum or blood. This occurs due to irritation or obstruction of the airways by the growing tumor.
Shortness of breath can develop as the tumor blocks airways or reduces lung capacity. Chest pain is another frequent complaint, often described as a dull ache or a sharp pain that intensifies with deep breathing, coughing, or laughing, indicating the tumor may be pressing on nerves or tissues in the chest.
Wheezing, a high-pitched whistling sound during exhalation, can result from narrowed airways due to tumor growth. Recurrent lung infections like bronchitis or pneumonia that do not respond to treatment or keep returning can signal an underlying issue, as the tumor may obstruct airways and prevent proper mucus clearance, creating an environment for infection. Hoarseness can also occur if the tumor affects nerves controlling the vocal cords.
General Body Symptoms
Beyond respiratory issues, lung cancer can cause non-specific symptoms that affect the entire body, often as the disease progresses. Unexplained weight loss is a common systemic symptom, where individuals lose a significant amount of weight without changes in diet or exercise. This can be accompanied by a loss of appetite, making it harder for the body to get necessary nutrients. Persistent fatigue and general weakness are also frequently reported, even with adequate rest. These symptoms are not unique to lung cancer and can be attributed to various less serious conditions, which can delay diagnosis.
Signs of Distant Spread
When lung cancer spreads to other parts of the body, it can produce symptoms specific to the affected organs. If the cancer spreads to the bones, individuals may experience pain, particularly in the back, hips, or ribs. Bones may also become weaker and more prone to fractures. Bone pain is reported in approximately 35-40% of people with advanced lung cancer that has spread to the bones.
Spread to the brain or nervous system can cause various neurological symptoms, including headaches, dizziness, balance problems, and seizures. Weakness or numbness in the limbs, as well as changes in vision or personality, can also occur depending on the specific area of the brain affected.
Liver metastasis can lead to symptoms such as jaundice (yellowing of the skin and eyes) and abdominal pain or swelling. Enlarged lymph nodes, particularly those in the neck or above the collarbone, can also indicate distant spread.
Remote Effects of Lung Cancer
Some individuals with lung cancer may experience remote effects known as paraneoplastic syndromes. These syndromes are caused by substances, such as hormones or antibodies, secreted by the tumor, which affect distant organs or tissues, rather than direct tumor invasion or metastasis. Paraneoplastic syndromes occur in approximately 10% of lung cancer patients and can sometimes appear before the cancer itself is diagnosed.
One example is hypercalcemia, or high blood calcium levels, which can lead to symptoms like nausea, constipation, frequent urination, increased thirst, and confusion. This occurs when certain lung cancers produce a hormone-like peptide that acts on bones and kidneys to increase calcium in the blood. The Syndrome of Inappropriate Antidiuretic Hormone (SIADH) is another endocrine effect, where excessive production of antidiuretic hormone by cancer cells leads to low sodium levels in the blood, potentially causing fatigue, muscle weakness, and confusion.
Neurological paraneoplastic syndromes can also manifest, such as Lambert-Eaton myasthenic syndrome, which causes muscle weakness, particularly in the legs, making it difficult to stand up from a sitting position. Other less common signs include clubbing of the fingers or toes, where the fingertips enlarge and the nails curve downward, and certain skin rashes.