Thanks. My Sister Had Severe Asthma As A Child. Recently

Thanks. My sister had severe asthma as a child. Recently she had a PET scan and from what she said she will have a biopsy because she has four nodules, two on each lung. They are large My question is is it possible that the activity picked up by the PET is scar tissue ? She said the largest one is smaller than a penny. She thought it was small but if it is cancer, that seems very large to me. Is it. Two three cancer centers in the U SA? Thanks