PSA bounces after primary radiation therapy are a common
phenomenon, occurring in a quarter to a third of patients. While some men might
prefer to see an uninterrupted PSA decline after treatment, studies have
demonstrated an association with 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% 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 many
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.
