Is a Cough That Won't Go Away a Sign of Lung Cancer?

Usually not, but it should not be ignored either. Most coughs come from colds, allergies, or reflux. A cough that does not go away, or gets worse over time, is one of the symptoms the National Cancer Institute lists for lung cancer. It is worth a doctor's look, especially if you smoke or have smoked. Where does "lasting" begin? The NHS puts its see-a-GP mark at a cough of more than 3 weeks.

There is no single telltale cough. What matters more is the pattern: a cough that will not go away, or one that changes — becoming deeper, more frequent, or different from your usual smoker's cough if you have one. Coughing up blood, even a small amount mixed into mucus, is a symptom the National Cancer Institute specifically lists and always needs prompt evaluation. Chest pain, shortness of breath, and unexplained weight loss are other symptoms that can appear alongside a lung-cancer cough, though not everyone has all of these.

Smoking is the leading cause of lung cancer by a wide margin. If you currently smoke, or used to, tell your doctor clearly when you describe your cough. This history changes how quickly your doctor may want to move to imaging, since the same cough carries different odds depending on your smoking history and age.

Colds and seasonal allergies cause most short-term coughs. Chronic bronchitis, common in smokers, causes a lasting cough that can persist for months. Acid reflux irritates the throat and airway, especially overnight, and causes a nagging cough in many people who do not realize reflux is the source. Asthma and certain blood pressure medicines can also cause a persistent cough.

Your doctor asks about the cough's duration, whether anything comes up when you cough, and your smoking history. A chest x-ray is the usual starting point, since it is quick and available almost everywhere. If the x-ray is unclear, or if your risk factors are high, a CT scan of the chest gives much more detail. If a spot or mass is found, doctors typically confirm it with a biopsy. A bronchoscopy passes a thin, flexible tube into the airways to look directly and take a tissue sample, or a needle biopsy may be used, guided by imaging, to sample a spot near the edge of the lung. Ask when the pathology report should come back.

A chest x-ray can miss small or early tumors that a CT scan would catch. If your cough continues for more than three weeks and you have risk factors like a smoking history, ask directly whether a CT scan is appropriate rather than waiting for the x-ray to explain everything.

• Call 911 or go to an emergency department if you are bringing up blood in more than trace amounts, or you are breathless while sitting still.
• Call 911 or go to an emergency department if chest pain comes on suddenly or is severe, rather than the ache of a strained chest wall.
• Call your care team the same day if you notice blood mixed into your mucus, however little, or a persistent soreness in the chest that has appeared alongside the cough.
• Call your care team within a day or two if the cough has carried on past three weeks, has changed from the cough you are used to, or is joined by weight loss you cannot account for.

• How long has my cough lasted, and does that change what tests I need?
• Should I have a chest x-ray or a CT scan?
• Does my smoking history change how urgently this should be checked?
• What symptoms should bring me back sooner?

• National Cancer Institute — Non-Small Cell Lung Cancer Treatment (PDQ)
• NHS — Cough