My granny is 70 yr old.doctors hav observed a small hole on her right lung n de r presuming it to b cancer .shud biopsy b done?

Yes: After adequate non invasive tests biopsy has to be done to establish diagnosis, pathologist is the only one who can give final answer, benign or malignant.

Difficult issue: How is your granny's health? If it is cancer, would she undergo radiation, chemo or surgery? A hole in the lung could be an easily treatable disease, like an infection. You, your granny and her doctor need to have an open discussion of the various outcomes of biopsy before proceeding with one.