THE “NEW” PROSTATE CANCER INFOLINK

A small but interesting study by Pinkawa et al. in Germany suggests that, as for return of potency after radical prostatectomy, patient age and pretreatment sexual function are the most important prognostic factors for the return of potency after external beam radiotherapy. The best predictor for preserving erections sufficient for sexual intercourse appears to be the occurrence of spontaneous erections in the morning or night, before treatment. Diabetic patients are not only predisposed for erectile dysfunction (ED) before radiotherapy, but also for post-radiotherapy-acquired ED.

It is widely accepted that there is a lack of prospective studies focusing on the sexual quality of life of prostate cancer patients after conformal radiotherapy (RT). The authors sought to evaluate the incidence, progression, and predictive factors for ED prospectively in patients undergoing conformal RT for localized prostate cancer at the University of Aachen.

The study included 123 patients, all of whom were treated with the same radiotherapy technique and at a homogenous dose level of 70.2 to 72.0 Gy. They received no antiandrogen treatment either before radiotherapy or during the follow-up period. However, 11 patients were using a phosphodiesterase-5  (PDE-5) inhibitor (a drug like Viagra) prior to RT. Patient age, comorbidities, prostate volume, planning target volume, pre-treatment sexual function, and treatment of erectile dysfunction were all considered.

Patients were asked to complete a detailed questionnaire on four occasions:

•  before RT treatment (time A)
• on the last day of RT treatment (time B)
• a median time of 2 months after RT treatment (time C)
• 16 months after RT treatment (time D)

Multiple risk factors (patient age, prostate volume, planning target volume, use of PDE-5 inhibitor, and comorbidities) were all tested for their independent effects on ED before and after RT.

The results obtained by the authors can be expressed as follows:

• Sexual function and bother scores had already decreased by the end of RT:
  • Median sexual function and bother scores at times A/B/C/D were 41/30/32/24, respectively. 
  • Median bother scores at at times A/B/C/D were 75/50/50/50.
• The ability to have an erection at times A/B/C/D was reported by 81/72/74/60 percent of patients (preserved erectile ability in 70 percent of patients at time D).
• The ability to have erections firm enough for sexual intercourse at times A/B/C/D was reported by 44/33/35/27 percent of patients (preserved erections sufficient for intercourse in 53 percent of patinets at time D).
• A higher patient age and a diagnosis of diabetes were predictive of both a pre-existing level of ED and a post-RT acquired level of ED.
• Nightly erections before treatment proved prognostically favourable (at least weekly as compared to less than weekly).

The results of this study support a progressively decreasing sexual function with longer follow-up intervals due to chronic effects of radiotherapy, patient age, and comorbidities. Based on these data, a stable level sexual function should not be expected in men with prostate cancer. However, chronic ED can be predicted with accuracy shortly after radiotherapy, which implies that ED cannot be regarded simply as a chronic effect of irradiation. As is often the case after radical prostatectomy, early initiation of treatment can improve erectile function after conformal RT in men treated for early stage prostate cancer.