This helps explain why lung cancer is the leading cause of cancer-related death in the United States, according to the National Cancer Institute. (1) Some people mistake early signs of lung cancer as nuisances rather than symptoms of disease. Smokers, for instance, may regard a persistent cough as simply a normal long-term consequence of their habit. Diagnosing and treating lung cancer in its earliest stages may improve your chances of survival, whatever your risk factors, per the American Cancer Society. (2) RELATED: Speaking Cancer: A Glossary of Formal and Informal Terms Used to Describe Cancer Tests, Treatment, Patients, and More

Earliest Warning Signs and Symptoms ofLung Cancer

Some common symptoms of lung cancer include, according to LungCancer.com:

Coughing, especially if it persists or becomes intensePain in the chest, back, or shoulders unrelated to pain from coughingShortness of breathChanges in the voice or being hoarseWheezing or harsh sounds with each breath (stridor)Recurrent lung problems, such as bronchitis or pneumoniaCoughing up phlegm or mucus, especially if it’s tinged with bloodCoughing up blood (3)

What Is Usually the First Sign of Lung Cancer?

While signs of lung cancer vary from person to person and may differ based on the size and location of the tumor, one of the most common symptoms is coughing, which occurs in about one-half of cases. The cough is often described as hacking or raspy, and may cause phlegm or mucus to come up. Typically, this cough doesn’t go away or get better. If you have a persistent cough, tell your doctor immediately, notes the GO2 Foundation for Lung Cancer. (4) RELATED: 6 Must-Dos After a Lung Cancer Diagnosis When cancer metastasizes, it can cause different symptoms, depending on the area of the body it affects. Symptoms of metastatic lung cancer may include:

Bone pain (as in pain in hips or back)Nervous system changes (headache, weakness or numbness in an arm or leg, dizziness, balance problems, seizures), if the cancer has spread to the brainYellowing of skin and eyes (jaundice), if the cancer has spread to the liverSwelling of lymph nodes (immune-cell clusters), such as those in the neck or above the collarbone (2)

RELATED: How to Talk to Your Doctor About Metastatic Non-Small-Cell Lung Cancer Pain

Non-Small-Cell Lung Cancer Symptoms

Non-small-cell lung cancer, responsible for between 80 and 85 percent of all lung cancers, can cause persistent cough, chest pain, shortness of breath, and other symptoms, per the Dana-Farber Cancer Institute. (5)

Small-Cell Lung Cancer Symptoms

Small-cell lung cancer, responsible for 15 to 20 percent of lung cancer cases, typically causes symptoms that are similar to those of non-small-cell lung cancer. But small-cell lung cancer tends to grow and spread faster than non-small-cell lung cancer. (5) About 70 percent of people with this type of cancer will have advanced disease by the time it is diagnosed, meaning their symptoms may reflect metastatic disease, notes the American Cancer Society. (6)

Is Back Pain a Sign of Lung Cancer?

There are many reasons for back pain, including, rarely, cancer. Around 1 in 4 people with lung cancer say they have experienced back pain at some point. The pain may come from a tumor pressing on the spine or affecting nerves around the chest wall and spine. Lung cancer that has metastasized to the spine may also cause back pain, notes the Dana-Farber Cancer Institute. (7) RELATED: 6 Steps to Take After You’ve Been Diagnosed With Metastatic Non-Small-Cell Lung Cancer

Superior Vena Cava Syndrome Symptoms

Sometimes lung tumors can press on a large vein in your body called the superior vena cava. This can cause blood to back up in the veins and lead to:

Swelling in the face, neck, arms, or upper chestHeadachesDizzinessChange in consciousness (if it affects the brain) (2)

Horner Syndrome Symptoms

Lung tumors that are located at the top part of your lungs, sometimes called Pancoast tumors, can affect facial nerves. This is known as Horner Syndrome and can cause symptoms such as:

A drooping eyelidA small pupil in the same eyeLack of sweating on the same side of the face

These tumors can also occasionally cause severe shoulder pain. (2)

Paraneoplastic Syndromes Symptoms

Paraneoplastic syndromes occur when lung cancer cells create hormone-like substances that can enter your bloodstream, or occasionally because the cancer makes your immune system attack some of your own tissue, such as your nerves. These syndromes may lead to symptoms like:

Nausea or vomitingMuscle weaknessFluid retentionHigh blood pressureHigh blood sugar levelsConfusionTrouble swallowing or speakingBlood clotsEasy bruisingLoss of balanceSeizuresComa (2)

RELATED: 9 Ways to Relieve Anxiety When You Have Metastatic Non-Small-Cell Lung Cancer

What to Do if You Have Symptoms of Lung Cancer

If you experience any signs or symptoms of lung cancer, make an appointment to see your doctor right away. Diagnosing lung cancer at its earliest stages gives you more treatment options and in general a better prognosis (outlook). If you smoke and have been unable to quit, make an appointment to see a doctor whether or not you have symptoms. Your doctor can recommend strategies for quitting, such as counseling, medication, and nicotine replacement products, notes the Mayo Clinic. (8) For some people with an extensive smoking history, the American Cancer Society recommends a yearly low-dose computerized tomography (CT) scan to look for lung cancer. (9) Don’t wait to get checked out. The earlier your lung cancer is diagnosed, the better your outcome is likely to be. RELATED: Metastatic Non-Small-Cell Lung Cancer Treatment: How to Be Your Own Advocate Additional reporting by Pamela Kaufman.