Lung cancer is the second most common cancer diagnosed in both women and men in the United States. When detected at an earlier stage before it metastasizes (spreads), treatment for lung cancer is more likely to be successful.
Many people with lung cancer do not have symptoms until the disease has progressed. Early symptoms of lung cancer include persistent cough, chest pain, shortness of breath, unexplained weight loss, hoarseness, and frequent lung infections (eg, bronchitis).
Because other common diseases can mimic lung cancer, people who do experience early lung cancer symptoms may mistake them for another issue, such as an infection. It’s important to see a healthcare provider promptly for any persistent and unusual symptoms, such as shortness of breath or a nagging cough.
This article will cover the diseases that mimic lung cancer, symptoms to watch out for, and how to get an accurate diagnosis.
Symptoms of Lung Cancer
Because the lungs do not have many nerve endings, many people with lung cancer do not notice or experience symptoms until the disease has metastasized.
It’s important to stay aware of your body and look for any changes or symptoms, especially if you are at high risk of developing lung cancer. The earlier lung cancer is detected, the easier it is to treat.
Common symptoms of lung cancer include:
Risk Factors for Lung Cancer
A risk factor is something that increases the likelihood of a person getting a disease. Common risk factors for lung cancer include smoking, secondhand smoke, exposure to pollution or cancer-causing toxins (eg, asbestos, radon), and a personal or family history of lung cancer.
Conditions With Similar Symptoms
Many medical conditions cause similar symptoms to lung cancer. Shortness of breath and a cough, for example, are commonly associated with a number of diseases. The following conditions have overlapping symptoms that may be mistaken for lung cancer (and vice versa).
Bronchitis is inflammation of the bronchial tubes—the main air passages to the lungs. Symptoms include coughing (often with mucus), chest pain, shortness of breath, and wheezing.
There are two types of bronchitis: acute and chronic. Acute bronchitis often occurs after a viral respiratory infection and typically clears up on its own within a few days or weeks. Chronic bronchitis can last for several months or years.
Pneumonia is a lung infection caused by a viral, bacterial, or fungal infection. The condition causes the alveoli (air sacs) in the lungs to fill up with fluid or pus and leads to inflammation of the airways. Pneumonia can affect one or both lungs and range from mild to severe. Symptoms include chest pain when breathing or coughing, chills, cough, fever, and shortness of breath.
Bronchiolitis is inflammation and swelling of the smallest airways in the lungs, called bronchioles. It is most commonly caused by a viral infection, such as influenza or respiratory syncytial virus (RSV). Bronchiolitis symptoms include a cough (with or without mucus), mild fever, rapid breathing, fatigue, shortness of breath, and wheezing.
Allergies occur when you’ve been exposed to an allergen (eg, pollen, pet dander, mold) and your immune system perceives this substance as a threat. In response, the body releases chemicals called histamines that can affect the respiratory system. Common allergy symptoms include congestion, sneezing, swelling, rash, and asthma.
Depending on the severity of allergies, symptoms may also include chest tightness, cough, shortness of breath, and wheezing.
Asthma is a chronic disease that affects the airways of the lungs. With asthma, certain triggers such as pollen, infection, or smoke can cause the airways to become inflamed and narrowed. The constricted airways can make it difficult to breathe. Common asthma symptoms include cough, chest tightness, shortness of breath, and wheezing.
COVID-19 is a disease caused by the virus SARS-CoV-2, which belongs to the family of coronaviruses. Though COVID-19 is not a respiratory disease, it can affect the respiratory tract and lead to symptoms that may mimic lung cancer. Common symptoms of COVID-19 include congestion, dry cough, fatigue, shortness of breath, and difficulty breathing.
Cystic Lung Diseases
Cystic lung diseases (CLD) are a group of lung disorders that are associated with multiple fluid or air-filled cysts bordered by a thin wall on the lungs. Common CLDs include lymphangioleiomyomatosis (LAM), pulmonary Langerhans cell histiocytosis (PLCH), Birt-Hogg-Dube syndrome, and amyloidosis. Common symptoms include difficulty breathing, chest pain, and cough (with or without blood).
Certain heart problems—such as coronary artery disease, heart attack, and valve disorders—can lead to heart failure. Heart failure develops when the heart is weakened and has difficulty pumping blood efficacy throughout the body. This can cause pulmonary edema—an excess build-up of fluid in the lungs that reduces oxygen flow, making it harder to breathe.
Pulmonary edema causes symptoms such as shortness of breath, chest pain, and cough (with or without blood).
If you are experiencing lung cancer symptoms, your healthcare provider will want to review your health and family history and perform a physical exam to determine the cause.
In order to provide an accurate diagnosis, your healthcare provider may order diagnostic tests, including:
- Imaging tests: Chest X-rays, computed tomography (CT) scan, magnetic resonance imaging (MRI) scan, and/or a positron emission tomography (PET) scan are imaging tests that take pictures of your lungs to help determine the cause of your symptoms.
- Lab procedures/tests: Examining cells from your lungs can help provide an accurate diagnosis. The cells may be taken from mucus you cough up or from fluid build-up surrounding the lungs.
- Biopsy: If imaging tests detected a nodule (or mass) on your lungs, a small sample of the nodule will be taken using a needle or through surgery to complete a biopsy and determine if it is cancerous.
When to Seek Medical Attention
See your healthcare provider if you experience any symptoms of lung cancer, such as a persistent cough, coughing up blood, hoarseness, frequent lung infections and/or wheezing.
Chest pain, coughing, fatigue, and shortness of breath are symptoms associated with a number of diseases. These common symptoms may lead to certain diseases—such as asthma, allergies, pneumonia, COVID-19, heart disease, bronchitis, and bronchiolitis—to be mistaken for lung cancer. Due to the overlap of symptoms, misdiagnosis is a concern.
It’s important to see a healthcare provider promptly for any persistent and unusual symptoms, such as shortness of breath or a nagging cough. In order to provide an accurate diagnosis, they will perform a physical exam and may order diagnostic tests, such as imaging scans and lab tests to examine your lungs and lung cells. Getting an early and accurate diagnosis can ensure you get the most effective treatment.
A Word From Verywell
Because so many diseases cause symptoms that mimic lung cancer, some people who go to their healthcare provider with symptoms may be misdiagnosed. If you have been diagnosed with and treated for a certain condition but your symptoms persist, it may be helpful to see your provider again or seek a second opinion.
Lung cancer responds best to treatment when detected early, so a timely, accurate diagnosis is essential. Be your own advocate and ask for further diagnostic tests to determine the cause of your symptoms.
Frequently Asked Questions
Is lung cancer often misdiagnosed?
Lung cancer misdiagnosis is relatively common, particularly in the earlier stages of the disease when it is harder to detect. Approximately 90% of all missed lung cancer cases occur on chest X-rays.
Common reasons for misdiagnosis include observer error (radiologists misreading the scan) and undetected lesions. Using more sophisticated imaging tests such as CT scans and MRI can help reduce the likelihood of misdiagnosis.
How is lung cancer diagnosed?
Imaging tests such as chest X-rays, CT scans, MRI, and PET scans are used to detect lung cancer. Examination of lung cells—taken from lung secretions (mucus), fluid surrounding the lungs, or from a tissue sample obtained through a biopsy provides the actual diagnosis obtained.
What are the early signs of lung cancer?
A nagging cough, chest pain, fatigue, frequent lung infections, hoarseness, unexplained weight loss and wheezing are common early signs of lung cancer. The lungs do not have many nerve endings, which means many people with lung cancer do not have symptoms or notice any physical changes until the disease has spread (metastasized).