How To Estimate The Degree Of Enlarged Prostate

Using Digital Rectal Examination (DRE) to evaluate the size of the prostate and estimate the weight: 
1) Degree I, Enlargement: the size of the prostate is twice the normal size, the volume is 20 to 25ml and the estimated weight is 20 to 25 grams.
2) Degree II, Enlargement: the size of the prostate is two to three times the normal size and the central sulcus may disappear, and the volume is 25 to 50ml and the estimated weight is 20 to 50 grams.
3) Degree III, Enlargement: the size of the prostate is three to four times  the normal size, the finger can reach the bottom of the prostate and the central sulcus has disappeared, the volume is 50 to 75ml and the estimated weight is 50 to 75 grams.
4) Degree IV, Enlargement: the size of the prostate is more than four times bigger than the normal size of a prostate. The finger can not reach the bottom of the prostate, and one side or both sides of the central sulcus have disappeared, the volume of of the prostate is more than 75ml and the estimated weight is above 75 grams.