Inquiring minds want to know: Does frequent ejaculation reduce risk for prostate cancer?
Can "cleaning the pipes” eliminate the accumulation of potentially toxic substances that may underlie cancer development? Inquiring minds want to know.
Question: What is the relationship between ejaculation and prostate cancer risk?
Dr. Loeb answers: This question was the focus of a prospective study from Harvard published in European Urology (https://pubmed.ncbi.nlm.nih.gov/27033442/). Using data from more than 31,000 males participating in the prospective Health Professionals Follow-up Study, Rider and colleagues looked at the relationship between ejaculation frequency and prostate cancer risk.
The basis for this research was the “prostate stagnation hypothesis,” suggesting that cleaning out “the pipes” may eliminate the accumulation of potentially toxic substances that may underlie cancer development.
The results of the study were exciting and highly quoted. Compared to 4-7 ejaculations per month, having at least 21 ejaculations per month at age 20-29 years and 40-49 years was associated with a significantly lower risk of subsequently being diagnosed with prostate cancer (19% and 22% lower hazard ratio, respectively).
Generally, this study is seen as good news for many patients and families. I have featured this study on my SiriusXM radio show several times, and live callers have asked me to repeat the results for their partner (“Tell my partner that we need to have more sex to reduce my risk of prostate cancer.”)
It’s important to note that the researchers did not specify the activity leading up to ejaculation (e.g., intercourse versus masturbation, etc).
This study has also triggered a lot of discussion on social media, including some misinterpretations.
For example, some people have asked if 21 ejaculations per month is associated with approximately 20% lower risk, would 5x that number of ejaculations (e.g. 105 ejaculations per month) could you essentially eliminate 100% of your prostate cancer risk?
Unfortunately, it doesn’t work like that and the group with ≥21 ejaculations per month comprised the highest category in the analysis. No amount of ejaculations was associated with a 100% reduction in risk.
Another topic of discussion in online networks is from people who are busy with work or other life events, leading them to miss the “target” of 21 ejaculations per month and triggering concern if this could affect their risk of prostate cancer.
People have asked if it’s possible to make up for a “slow month” by doubling up on the number the following month. It is important to keep in mind that the numbers in this study are rough categories based on people’s recall of the average number of ejaculations per month at different ages and the precision of these estimates is unclear.
While I believe that there may indeed be something to the prostate stagnation hypothesis (e.g., there is some data suggesting that ejaculation is associated with differential gene expression in prostate tissue (https://pubmed.ncbi.nlm.nih.gov/29784192/), 21 is not an absolute or magical number.
The final and most important key point is that we cannot prove a causal relationship based on this study. That is, we cannot say for sure that greater frequency of ejaculation causes a lower risk of prostate cancer.
These results are from an observational study, where people were followed over time as they were living their normal lives. It was not a randomized trial where people were randomly assigned to different frequencies of ejaculation. The authors acknowledge that ejaculation frequency could be a marker of health status and did a series of statistical adjustments to take into consideration other factors that might affect the results. Even so, there may be other unmeasured differences between the people with more ejaculations per month that may affect their prostate cancer risk.
Dr. Stacy Loeb is a Professor of Urology and Population Health at NYU Langone Health and the Manhattan Veterans Affairs, specializing in prostate cancer. Dr. Loeb completed her urology residency training at Johns Hopkins and subsequently received a Master of Science in Comparative Effectiveness Research at NYU School of Medicine.
Dr. Loeb is an internationally recognized expert in prostate cancer with more than 340 peer-reviewed published articles and 11 book chapters. She is on the Editorial Board for the Journal of Clinical Oncology, European Urology, Urology Times, Nature Reviews Urology and Reviews in Urology. Dr Loeb authored the chapter on “Diagnosis and Staging of Prostate Cancer” for Campbell-Walsh Urology, the primary textbook used in the field of urology.
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ASPI holding exercise webinar April 27
Active Surveillance Patients International is holding a webinar on exercise and how it helps patients with prostate cancer. The free program, “How Can Exercise Help Prostate Cancer Patients Like Me?”, will be held from noon to 1:30 pm Eastern Saturday, April 27, 2024. Register Here
The program includes the premiere of the latest in the Active Surveillance (AS) 101 video series, featuring a real couple, Nancy and Larry White, interviewing an exercise expert, Kerry Courneya, PhD, whose research has proven the benefit of exercise in slowing low-grade prostate cancer.