Difference between lung cancer and asthma, expert explains

Symptoms of asthma and lung cancer can be indistinguishable in the early stages, and even laymen— and sometimes, doctors — might have a hard time telling the difference without further analysis. This intersection may cause confusion, or delay the decision to diagnose problems, particularly when patients continue to have symptoms even after management.

Asthma is often a chronic inflammatory disease that is controllable with inhalers and medications, while lung cancer is a life-threatening disease that generally requires more aggressive measures. The trends, the aetiology, and the consequences of the two are quite different.

Physicians pay close attention to the patient’s history, lifestyle, age and symptom pattern to correctly diagnose the disease. When symptoms don't subside as expected, diagnostic testing including with imaging, blood tests and pulmonary function testing may be required.

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Appreciation of these subtle but important differences is critical for early recognition and management. Early identification and medical examination are essential if the symptoms of respiration persist or shift over time, says Dr Mandeep Singh Malhotra, Director Surgical Oncology at the CK Birla Hospital, Delhi.

• Cough that won’t quit

Asthma-associated cough usually improves with bronchodilators or corticosteroids. On the other hand, chronic cough that doesn't improve with treatment and last more than 2–3 weeks could be an early symptom of lung cancer if it continues to get worse or if you cough up blood or a blood-stained sputum.

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• Seasonal presentation

Seasonal symptoms such as changes in weather or allergens lead to asthma symptoms. Even if mistaken, lung cancer doesn’t seem to come and go with the seasons, it comes and goes without warning in Yonkers.

• Breathlessness

Asthma-related breathlessness usually is episodic – occurring most frequently at night or with exercise – and responds to medication. In lung cancer, shortness of breath progressively worsens and does not always improve with bronchodilators.

• Other signs:

Asthma can also manifest with wheezing, tight chest and allergic signs. Lung cancer may also cause more alarming symptoms, such as unexplained weight loss, constant fatigue, loss of appetite, hoarseness or chest pain.

• Response to treatment

Asthma generally responds very well to treatment. When the response is either modest or zero in front of treatment, it is time to look deeper.

• Diagnosis is key

In the case of asthma, the chest X-ray will often be normal and diagnosis is established through history taking and lung function testing. For suspected lung cancer, it’s possible a CT scan, a bronchoscopy, or a biopsy may be ordered for a clearer picture.