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In about 35 percent of all patients with prostate carcinoma treated by brachytherapy, a primary drop in prostate-specific antigen (PSA) is followed by a renewed rise in PSA, which again falls spontaneously after some time. Such a temporary PSA increase usually occurs 1 to 1 ½ years after brachytherapy and recovers after an average of 18 to 20 months. The reason for such a PSA bounce is usually radiation-induced inflammation of the remaining prostate tissue (prostatitis), which, however, does not require treatment.
A PSA bounce after brachytherapy therefore does not indicate renewed tumor growth in the prostate (local recurrence) in most cases and is not due to a poor brachytherapy outcome. In fact, numerous studies have shown that patients with a PSA bounce were even less likely to develop PSA recurrence than patients without a PSA bounce and thus had a very good prognosis for disease. For example, a recent study from Switzerland in 2015 showed that the risk of biochemical recurrence is reduced by more than 75 percent in patients with a PSA bounce.
There is no reason to worry if the PSA level rises again after brachytherapy. It is important to keep an eye on the overall situation and not to initiate treatment prematurely. In such situations, it makes sense to check the PSA level at three- to six-month intervals in accordance with the ASTRO criteria. The misdiagnosis of a PSA recurrence and its unnecessary therapy, as well as the patient's concern about a disease recurrence, can be avoided if the physician and patient are educated about the characteristic features of a PSA bounce.
Literature:
Engeler DS et al: PSA bounce after 125 brachytherapy for prostate cancer as a favorable prognosticator. Radiation Oncol. 2015 Oct;191(10):787-791. epub 2015 Jun 23.
Caloglu M et al: PSA Bounce and Biochemical Failure After Brachytherapy for Prostate Cancer: A Study of 820 Patients With a Minimum of 3 Years of Follow-Up. Int J Radiat Oncol Biol Phys. 2010 Jun 18.
Critz FA et al: Prostate specific antigen bounce after radioactive seed implantation followed by external beam radiation for prostate cancer, USA.J Urol 2000 Apr;163(4):1085-9.
