Relationship between sexual function and prostate-specific antigen bounce after iodine-125 permanent implant brachytherapy for localized prostate cancer

Objective To analyze clinical and dosimetric factors involved in prostate-specific antigen bounce in patients who underwent permanent implant brachytherapy for localized prostate cancer, and to study the relationships among prostate-specific antigen bounce, age and sexual function. Methods Between March 2007 and April 2012, 116 patients with localized prostate cancer underwent permanent implant, iodine-125 brachytherapy. Patients receiving external-beam radiotherapy or who used phosphodiesterase-5 inhibitor pre- or post-treatment were excluded. Prostate-specific antigen bounce was defined as an increase of ≥0.2 ng/mL and ≥0.4 ng/mL above an initial prostate-specific antigen nadir followed by a subsequent decline to or below the initial nadir without treatment. Clinical and dosimetric factors involved in prostate-specific antigen bounce were analyzed using multivariate logistic regression analysis with the forced entry method. Results The median age was 66 years (range 51–80 years), and prostate-specific antigen bounce on a prostate-specific antigen rise of ≥0.2 ng/mL occurred in 47 of the 116 participants (40.5%). The median period before the prostate-specific antigen bounce was 17.5 months (range 8–36 months). Patients with prostate-specific antigen bounce were younger and had higher sexual function before treatment (P = 0.003) than those who not show prostate-specific antigen bounce. Regression analysis results showed that young age and a high level of pretreatment sexual function were significant predictive factors for prostate-specific antigen bounce (P = 0.028 and P = 0.048). Conclusion Sexual function seems to be associated with a prostate-specific antigen bounce in patients undergoing permanent implant brachytherapy for localized prostate cancer, and it can be preserved after treatment if it is well present before treatment. Highly maintained sexual function after treatment might influence prostate-specific antigen bounce.