PSA “bounces” are (relatively small) increases in a patient’s PSA level from a lowering level after completion of primary radiation therapy The size of such bounces can vary significantly — from as little as 0.1 ng/ml to as much as 2.0 ng/ml or more … and they can be very worrisome.
Such PSA bounces are a common phenomenon, occurring in a quarter to a third of all first-line radiation patients. While some (or even most) men might prefer to see an uninterrupted PSA decline to a final nadir level after treatment, studies have demonstrated an association between the occurrence of bounces and improved cancer control. Studies also find higher incidence of bounces in younger men. Perhaps related to that, we now see that there is an association between bounces after brachytherapy and erectile function, sexual activity, and sexual satisfaction.
Matsushima et al. examined the records of 154 patients who had been treated with brachytherapy, and whose sexual function was self-assessed at baseline and continually for up to 3 years. Among those men, 25 percent experienced a PSA bounce of at least 0.4 ng/ml above the previous PSA reading, and they experienced that bounce a median of 18 months after therapy.
Compared to the men who did not have a bounce, those who did reported higher scores on all measures of sexual performance at baseline and at all time points afterwards. “Bouncers” had higher scores on:
- Erectile function
- Orgasmic function
- Sexual desire
- Intercourse satisfaction
- Total International Index of Erectile Function-15 Score
The authors also conclude: “an occurrence of prostate-specific antigen bounce seems to be more likely in those who are more sexually active.”
While it’s tempting to infer causal relationships, there are many possible reasons for this observation. It’s possible to put forward numerous hypotheses, none of which are proven:
- Younger men have better sexual performance, and it may just be a coincidence that they are more likely to have bounces.
- Because PSA readings are affected by recent sexual activity, those with bounces had sex closer to the date of their PSA test.
- Sexual activity promotes health of the sexual apparatus, and deters radiation-induced scar-tissue formation.
- Older cells may be more prone to immediate killing by radiation, while cell-cycle arrest, which may delay apoptosis, may be more likely in younger cells.
Whatever the reason behind the association, it provides one more reason not to worry about bounces after radiation therapy.
Editorial note: This commentary was written for The “New” Prostate Cancer InfoLink by Allen Edel, who brags that he had three PSA bounces. ;-)
Filed under: Living with Prostate Cancer, Management, Treatment | Tagged: bounce, PSA, radiation, therapy |
THE "NEW" PROSTATE CANCER INFOLINK 
Allen:
REALLY! … Bragging, huh? … I’ll bet you weren’t bragging when you had the first bounce. I’ll put money on the idea that something else was going on entirely!
:O)
Well, at the time I didn’t know that it meant I was such a stud. Hindsight is 20/20. Fortunately, my radiation oncologist had warned me several times that it might happen. Where it really gets troublesome is in men who have relapsing and remitting prostatitis. The increases can exceed 2.0 ng/ml, which is really nerve-wracking.
We know from monitored PSA data that some men (only a quarter to a third according to the article) witness a post-RT “bounce.” What we don’t know, I believe, is whether or not all men who undergo RT experience bounce, perhaps unbeknownst to two-thirds to three-quarters of patients. Perhaps all do, but some have not had the frequency of PSA data collected necessary to reveal the phenomena.
The “amplitude” of the bounce varies widely amongst “bouncer” patients (as noted in the article), but what we don’t know (I believe) for each case is whether that specific day’s PSA test result is at the peak of the bounce, on the way up to a yet-to-be-reached peak, or on the way down after a previously-reached peak. But for others the day of their PSA monitoring test may simply have fallen in a period of time when the bounce is in the “valley” between two peaks; for these, it may appear that no bounce has occurred.
Nor have we (to my knowledge) mapped the duration of either the peaks or the valleys of the bounce. Probably no two men are exactly alike in this regard, and again it probably varies widely person-to-person and upon individual cancer biology. Nor do we know the frequency of the bounces or when they will show up, and again this will likely vary widely.
Indeed, it seems likely to me that more men experience post-RT than realize it due completely to the infrequency of PSA measurement. Perhaps all do experience bounces, and only those with bounces of greater amplitude, duration, and frequency end up getting identified.
The article notes that bounces are seen more frequently in younger men. Is this merely an artifact of more frequent follow-up PSA testing amongst younger men? This postulation would also explain the higher measures of sexual performance measures amongst bouncers.
I agree with the big picture that bounces appear to not be anything to worry about, but I don’t think we really know much about the phenomena. Perhaps someone knows whether the “mapping” of a set of post-RT PSA history — perhaps through daily monitoring — has been reported. (I should add that I read Matsushima’s abstract only, not the full paper.)