Dad is booked in for key hole surgery to get biopsy of growth on plural of lung. had fluid drained no cancer cells in there - diagnosed with pneumonia from bloods in ed. previously worked with asbestos. what else could it be other than cancer?

The growth may represent scar tissue, and it is reassuring that there were no cancer cells. Follow up with your PCP regarding cancer blood biomarkers, particularly if you have symptoms. An infection of the lungs and lining of the lungs may be the underlying cause, and ruling out TB is another consideration.

Your dad probably has asbestosis with benign pleural effusion and it was found incidentally by radiologic imaging tests when he had pneumonia. They do pleural biopsy to rule out maligant mesothelioma. Asbestosis is a also a risk factor for non small cell lung cancer but the fluid is negative for K cell and likely CT chest is also negative so he likely does not have non small cell cancer.

In my experience, pleural effusion caused by community acquired pneumonia is usually preceded by pleuritic pain, namely sharp chest pain on taking in a breath. The fluid accumulation then follows after several days. Mesothelioma still has to be a consideration in view of the history of asbestos exposure. Not all lung cancer cases show positive cytology of the pleural fluid.