I had recurrence 18 months after surgery so not the same but...time to gather some clinical data to inform a decision between you and your medical team. You should have the Pathology report and your surgeon should have discussed with you his notes. In my case the pathology report was T2CNoMx, GS 4+4, ECE, Margins, and SV Negative, 10% involvement.

Next will be determining PSA doubling and velocity which generally needs three PSA results, there is some discussion about the spacing between those, three months. There are online calculators, Memorial Sloan Kettering has one.

Finally, with a PSA of .7, you may want to image using one of the recently approved FDA scans - https://www.fda.gov/drugs/drug-safety-and-availability/fda-approves-second-psma-targeted-pet-imaging-drug-men-prostate-cancer

Informed by that clinical data , your research and your medical team, you can make a decision whether to treat, if so, when and with what. It may be, monotherapy such as radiation or a combined regimen involving radiation and short term ADT, say six months.

I was definitely "disappointed" when my prostate cancer returned after surgery, after I got over the feelings, anger, frustration..I gathered the data and made my next decision. I chose not to "look back" about my decision to do surgery and focus on the next decision I needed to make.

I was diagnosed in Jan 14 at age 57, like your husband, the result of a colonoscopy (PSA was 2.1, my mistake was not having a DRE one during annual physicals but since the PSA was 2.1, who knew...!), surgery in Mar 14, BCR in Sep 15, SRT in Mar 16, then 18 months of ADT, six cycle of taxotere and 25 IMRT to the pelvic lymph nodes. I finished that regimen in August 2018 and it's now three years, other than seeing my urologist every two-four months for labs and consult, no further treatment.

Your husband may have advanced prostate cancer, If so, SRT may "cure" it but there is discussion that the best chance to do so may be at lower PSA than what your husband currently has. This may now be a case of managing a "chronic disease." In the seven years since my diagnosis much has changed, to the better, imaging, treatment modalities,

Kevin