I am 58 yrs old. I am using urimax-.4mg from 2003. Weight of prostate was 19gm in 2003, 26 gm in 2007, 31gm in 2012 & now in Agust,2015 is 23 gm. Residual urin is 40ml, 54ml, 60ml & 70ml respectively. Is operation essential ? Or use urimax. What are the merits & demerits.