The most common disease with which lung cancer gets confused with is Tuberculosis (TB) in Singapore. This is because TB is almost as common as lung cancer in Singapore and Asia—1300 new cases of TB and 1500 cases of lung cancer every year in Singapore. They look alike on the chest x ray. TB affects the upper parts of lung and so does lung cancer.
The shape and features of the white spot in the lungs caused by TB (cavity) is similar to the appearance of the spot caused by lung cancer. Hence if one is not careful, one may think that he is dealing with TB when actually patient may be having cancer. This issue is compounded by the fact that the confirmatory result of TB takes 2 months even in this day and age. So if one decides to start a trial of TB treatment while waiting for its confirmation, and if the patient is having cancer all this while, you end up delaying the diagnosis by 2 months which can be detrimental.
Younger age group of TB patients, and historical association of smoking with cancer adds to the confusion as it can make doctors think that if patient does not smoke, or is too young, he cannot be having cancer when the truth is that lung cancer has become more common in non-smokers and affect people as young as 30 year old. In some cases where a person had TB long ago which has been treated and now healed, a lung nodule can be falsely considered a scar from old TB based on the chest X-ray creating a false sense of security when it could actually be lung cancer.
What you can do? Active TB of the lungs usually makes people sick. Common symptoms are cough of prolonged duration (usually 2-3 weeks), loss of weight, prolonged fever (usually in the evenings), fatigue, coughing out blood, excessive sweating especially at night, generalised weakness. Since TB is contagious, a person who has TB usually has a history of exposure to someone who had TB in the family or friends in the past.
If you don’t have such symptoms or history of exposure to TB patient in the past, your chest X-ray abnormality may not be due to TB but cancer instead. This is because it is a feature of the lung cancer to be silent and cause no symptoms at all especially in the early stage—stage where it can be cured if picked up in time.