I am really sorry to hear of this. I am fully on board with what my urologist said when I asked about my options when I was first diagnosed as a Gleason 3+4=7, which was/is: "You HAVE cancer...there is no point watching and waiting for two years of Active Surveillance...your cancer is only going to get worse." That is exactly what has happened to you, quite unfortunately. Your doctor could have removed your likely "capsule-contained" prostate without any additional pathology. Now that your cancer has progressed to a Gleason 3+4=7, you could...you "will"...have more pathology. I just wrote this in another reply, but the Gleason Score is just "the tip of the iceberg". My urologist was overly confident, even with my Gleason 3+4=7, that "we caught it early." Well, this is where the big, ugly part of the iceberg lurking beneath the water shows itself. Once my prostate was removed it revealed a much more advanced pathology and degree of cancer. My urologist was quiet and solemn saying "your cancer is more advance and aggressive than I thought." In quick succession, without offering the detail (you can quickly Google it), I also had Extraprostatic Extension ("EPE"), Surgical margins, Cribriform Glands, and (left) Seminal Vesicle invasion, all of which took me from a low-Moderate Risk Gleason 3+4=7 that should have only been a T1 or T2 cancer, to a class/category called pT3b which is much worse...the definitive thing being that there was seminal vesicle invasion. Even though my urologist removed both seminal vesicles and both vas deferens with the prostate, the fact that the cancer entered my left seminal vesicle (no nodule or tumor though), took me to that pT3b category which means that I have a 25%-50% likelihood of the cancer coming back "within" five years. The "lesson" learned is that I would not have known any of this and how bad my cancer is, if I had just relied on my Gleason Score and insisted on Active Surveillance. All of that extra pathology was seen with the prostate tissue examined in detail microscopically, after it was removed. What I am saying, is that even with a Gleason 3+3=6, you may still have more advanced cancer pathology happening than the Gleason Score might suggest. And...
As I offered in my other reply to a post here: make sure you have your biopsied tissue sent to Veracyte Labs in San Diego, CA for their proprietary test called the Decipher Test. It is a test for 22 prostate-cancer-specific genes that will tell you how your cancer story will unfold. It is a test that yields a score from 0.1 to 1.0. You want your score to be as low as possible, meaning you have fewer cancer genes or fewer of the worst cancer genes. The good news is, like with me having a Decipher Test score of 0.50 - "dead middle" of the range, my 5-year, 10-year, and 15-year risk of death (shorter longevity) is still only in the 4% - 7% range, meaning I have a 93% - 96% chance of still being alive at 5-, 10-, and 15-years in my post-prostatectomy cancer journey. I had whatever cancer genes I have, but they aren't the bad ones.
My bottom line suggestion: I would not do Active Surveillance any further. I'd have the prostatectomy while there is a much lesser likelihood of those things mentioned above that will make things much more difficult: EPE, surgical margins, Cribriform glands, seminal vesicle invasion, etc. This is just "my opinion." I am clinically trained, having spent 40 years as a Director of Clinical and Anatomical Pathology services in hospital and commercial labs, so I have a little more knowledge or perspective, but again...do what your physician suggests, get a second opinion if you feel the need to, and do what you feel is best for you. Good luck!
Good luck to you.