The eleventh publication of the Journal of Sexual Medicine’s methodology update series will be Dr. Bridget Koontz’s “Challenges in Reporting the Effect of Radiotherapy on Erectile Function," which was published in JSM’s June 2020 issue (https://doi.org/10.1016/j.jsxm.2020.03.008).

Bridget F. Koontz, MD, is a radiation oncologist at Duke University Hospital in Durham, NC, with research focusing on optimizing prostate cancer treatment.

To get a more in-depth understanding of the thoughts behind her paper, we conducted a text interview with Dr. Koontz:

1. What does the literature tell us about whether one RT modality is better than another regarding erectile function preservation?

“The current literature reports widely varied rates of ED after RT, so much so it can be hard to know what the risk truly is for the patient in front of you. Looking at modern series that take into account the factors we describe in the article, the risk of ED is probably very similar across the current radiation treatment modalities.”

2. Could you synopsize the impact of ADT on erectile function recovery?

“ADT has a huge effect on erectile function, certainly greater in the short term, but its effects can last long-term as well. We and others have reported that even men who only receive 4-6mo of ADT can have suppressed testosterone for 12-24mo after the medication is supposed to end.”

3. To define erectile function outcomes, what is the optimal time-point after RT for patient evaluation?

“For men who do receive ADT, one should really check serum testosterone regularly – I would not expect erectile function to recover until testosterone approaches the lower limit of normal. Half of patients reach that threshold by 12mo after the last injection. For those who undergo RT by itself, erectile function typically is normal immediately after RT and slowly falls. The RT-induced decline, which layers over natural aging changes, is typically evident by 24mo after RT.”

4. What future strategies do you think may be employed to reduce ED after RT?

“Technology to reduce the normal tissue “bystander” radiation has already reduced the ED rate from approximately 50% to 30%. I believe further improvements will require better understanding of the biology of radiation-induced ED and applying selective normal tissue radioprotectors to further reduce injury to pro-erectile tissues.”