Macro Adenona. Or can it be cured?

Im 31, Male. I have been detected with Macroadenoma through a MRI taken on Feb 2018. I did not have symptoms like severe headache. I went to an ENT for sinus problem and the macroadenoma was discovered in a scan and an MRI later. I then consulted an Endocrinologist. After his suggestion I took all the hormone test. It was detected that the prolactin level is high and testosterone is low. The Endocrinologist prescribed Cabergolin on Feb and suggested a 2nd MRI in May. The MRI in May showed that there is about 30% reduction in the tumour size compared to the first one. The Endocrinologist increased the Cabergolin dosage subsequently and asked for a 3rd MRI in December. The 3rd MRI showed a slight increase in size of the tumour but the prolactin is under control. The Endocrinologist is now saying that it is a non functional tumour and suggesting for TNTS surgery. I am confused on how the same tumour be prolactinoma and non functional. Should I go for surgery or can it be cured?