Why is the x-ray showing a patch on the lungs after TB treatment?

Q: My wife is undergoing treatment for pulmonary tuberculosis and she is taking medicines regularly as prescribed by her doctor. During her last follow up with the doctor, i.e. after one and a half months of treatment, the doctor has said that she improved clinically but her recent x-ray report shows that the patch on the lungs has not yet decreased and it is in the same condition. Is it something related to cancer? One of the doctors during the initial checkup and while referring to x-ray, CT Scan and bronchoscopy reports has said that there are 10 percent chances of cancer, but some doctors said that it is not a cancer and other doctors after looking at the reports informed us that if she is responding to the medicines prescribed for TB then there is no need to worry about it. Please advise why the patch on the lungs has not decreased in spite of being clinically improved and taking medicines regularly for one and a half month? Right now she is feeling quite well, there is no cough, no fever or any kind of pain but sometimes she feels tired. Please advise.

A:The radiological changes on x-ray take a much longer time to resolve and do leave a scar even after successful treatment of TB. You should not worry about this unnecessarily. Clinical assessment of treatment progress is largely subjective. Disappearance of clinical symptoms, general well-being, ability to resume normal activities, and weight gain are all pointers to clinical progress. Persistence or reappearance of symptoms plus weight loss – indicates the need for further investigations by sputum microscopy. Erythrocyte sedimentation rate (ESR) and other tests are unreliable and unnecessary in monitoring progress. Clinical assessment is often the only means available for judging progress in extrapulmonary and smear-negative pulmonary tuberculosis: weight gain is a valuable indicator in such cases. Serial radiography is still preferred by many physicians, though several studies have shown that this can be very misleading for assessing the progress and eventual outcome of treatment. Bacteriologically quiescent disease may be classified as treatment failure because of residual lesions on the x-ray, including cavitation. Patients with persisting bacteriological negativity could show radiographic changes that would be interpreted as deterioration by expert assessors. Assessment by x-ray changes alone can be very misleading.