Andrew Stephenson, from Cleveland Clinic, a major researcher on the topic of SRT, along with Scardino and other leading lights, have shown that it's preferable to start SRT before PSA reaches 1.0, and optimally before it reaches 0.5.
, plus you can find this echoed by other researchers in various articles.
As to the definition of recurrence, this seems to be a matter of some debate as to exactly when the declaration is made. But generally it's 0.2. I think the debate is whether it's 0.2, or 0.2 and rising as confirmed by the next test. Here's what Judd Moul, of Duke University says:Recently, the American Urological Association published guidelines that establish the consensus definition of PSA recurrence after RP to be greater than 0.2 ng/mL and rising, as confirmed on a repeat test. This definition is to establish recurrence for outcomes reporting; however, it may not be the appropriate cutpoint to initiate therapy.
Indeed, it is our practice in a patient with a consistent and clearly rising PSA, often based on ultrasensitive values, to occasionally begin salvage radiotherapy when the PSA is between 0.1 and 0.2 ng/mL. Because microscopic or focal benign prostate tissue can sometimes be left behind after RP and may produce some small amounts of PSA, it is clinically important to recognize that a PSA of 0.2 ng/mL may not always represent cancer recurrence. Therefore, in the majority of patients, we do wait until the PSA is > 0.2 ng/mL before beginning salvage treatments.
Source: "Rising PSA in Nonmetastatic Prostate Cancer" www.cancernetwork.com/prostate-cancer/content/article/10165/63133
(free article, but registration is required.)
When my PSA hit 0.6, my uro finally was concerned enough to refer me to radiation and medical oncology (I consulted both but went with salvage radiation alone). I moved as quickly as I could, and the day before I started SRT, my PSA hit 0.7. Although so far things look good, in retrospect I wish I had been more proactive, knowing what I do now about
the importance of pre-RT PSA. It's far from the only factor, but it stands out as important.
You might want to take a look at my "knol", a Google document where I have summarized what I learned as an SRT patient on one page of Q&A, with references if you need more: knol.google.com/k/salvage-radiation-for-prostate-cancer
Dx Feb 2006, PSA 9 @age 43
RRP Apr 2006 - Gleason 3+4, T2c, NX MX, pos margins
PSA 5/06 <0.1, 8/06 0.2, 12/06 0.6, 1/07 0.7.
Salvage radiation (IMRT) Jan-Mar 2007
PSA 9/2007 and thereafter <0.1pcabefore50.blogspot.com