Study: Vasectomy and Risk of Prostate Cancer: A Systematic Review and Meta-analysis
Another meta-analysis published in April 2022 shows a link between vasectomy and prostate cancer.
CONCLUSIONS: Our meta-analysis found an association between vasectomy and any, mainly localized, PCa. However, the effect estimates of the association were increasingly close to null when examining studies of robust design and high quality. On exploratory analyses including studies, which adjusted for PSA screening, the association for aggressive and/or advanced PCa diminished.
Patient summary: In this study, we found an association between vasectomy and the risk of developing localized prostate cancer without being able to determine whether the procedure leads to a higher prostate cancer incidence.
https://www.sciencedirect.com/science/article/pii/S2666168322005870?via%3Dihub
Not too different from other analysis done recently.
Posted Jun 1, 2022, 8:33 PM UTC
Thanks for continuing to monitor for this.
Similar results to before, a little smaller effect observed.
To me, the interesting part is the way these scientists think about what they are seeing and communicate what they are seeing. For example:
What they saw was:
I guess you can truthfully say that the estimate of the association is "increasingly close to null" when you restrict the analysis to higher quality studies. You could also truthfully say that the association is "increasingly close to negative". In other words, "increasingly close to null" is another way to say "not null" if you want to avoid actually saying "not null."
They say they are unable to determine whether the procedure leads to a higher prostate cancer incidence. Is that really what their meta analysis is showing? What is the null hypothesis? Where is the burden of proof? Men with a vasectomy get diagnosed with prostate cancer more often. This is not in dispute. They do the meta analysis, and what does it show? Some of this phenomenon is explainable by PSA screening. But not all of it.
So this study is not failing to demonstrate that vasectomy causes prostate cancer. What this study is failing to demonstrate is that vasectomy does not cause prostate cancer.
In other words, the following expression of the conclusion is closer to the truth:
"In this study, we found an association between vasectomy and the risk of developing localized prostate cancer and cannot show that the procedure does not lead to a higher prostate cancer incidence."
But this is not how they write. Vasectomy is presumed to be innocent. They are still hoping to find something else to account for the residual increase in rate of cancer diagnosis:
What are these "potential residual confounders"? The bar is set pretty high. It looks like the only way to satisfy anyone that vasectomy is causing prostate cancer will be to do a study where you select men at random and give them a vasectomy. Of course that study will never happen, so I suppose we can never really know.
In the discussion they write:
In other words, yeah maybe there is some increased risk of prostate cancer, but in any event the risk "may be close to zero" so men should not stop getting vasectomies.
This is an interesting clause. What change to clinical practice are they talking about here? The only way I can read this line is that they are discussing whether or not doctors should start telling men before they get a vasectomy that it may raise their risk of prostate cancer.
This is quite a small needle that they suggest doctors thread. Somehow they should communicate to men that vasectomy is "associated" with prostate cancer, and that it is not yet known whether or not it may increase their risk of prostate cancer. Clearly the tension here is that the men deserve to know about this issue, but telling them is problematic because they might blow it out of proportion.
I appreciate your well crafted synopsis. I agree that they seem to be trying to find anything to show that a vasectomy doesn't increase your risk of prostate cancer when the data clearly shows that it does. How much can be debated but I really think this should be headlined and discussed more as prostate cancer has become a serious disease for men.
Another study:
https://www.nature.com/articles/s41416-022-01827-1
I was thinking about the PSA test thing... it's really hard to prove causation with an observational study.
Guys with personality type X are more likely to get a vasectomy, more likely to get a PSA test, and more likely to get diagnosed with prostate cancer.
Why? Some combination of these:
Somehow they all add up to about a 23% increase. But how much role does each play? This requires a clever study. You cannot simply subtract out the correlation with PSA testing, because of this dynamic:
Getting cancer does not decrease the rate at which you get a PSA test. If anything it is likely to increase the chances that you will get a PSA test. So some cancer diagnoses can be conveniently assigned to PSA test which were in fact caused by vasectomy if you are not careful to be impartial in how you handle it.
Yes I agree. I know some studies have tried really hard to remove these biases but unfortunately there haven't been enough.
I also think there is a reluctance to put out negative information as it could have serious societal impacts as we have seen with vaccines. I am sure you could argue the money making aspects as well. The lack of bc options for men with no viable replacement isn't going to play well socially. But I think we need to come to terms with the procedure having some serious flaws like other forms of bc and leave it to the individual to decide if it's worth it.
I happened to see the vasectomy-information treatment of prostate cancer after vasectomy:
Just in case their agenda was not obvious. They cannot mention prostate cancer without bringing up the risk of cancer due to birth control pills.
Just imagine the roles reversed there for a second. Imagine how it weird it would look in a discussion about birth control pills if there was a statement in there about how these come with a risk of cancer -- and we hasten to add that vasectomy can also cause cancer. It would seem really shoehorned in there. Like ok dude, how about we talk about that when we get to the vasectomy topic.
They also do the stats bait and switch on PVPS:
No, the kind that disappears within 6 months is the type that affects 15% of guys. The type that affects 1% of guys does not disappear within 6 months.
That's an interesting find about the cancer risk being equal to birth control pills risk as I haven't seen that written before regardless of context. BC pills seem to have pretty negative opinions in many threads on bc because of the side effects. However, I doubt many would accept this as a reason to not get a vasectomy. Vasectomies seem to be getting talked up a lot with all the roe v wade discussions and still most people do really understand the true risks involved. It would be interesting to see if the risks associated with a vasectomy were as accepted like the risks associated with women's bc if people would have a different take on men getting them.
My gut reaction to that is that I doubt it's the truth. Cancer risk for OBC pills seems like it would be higher than the risk suggested by the 2019 study.
Regarding how society feels about vasectomy, and whether or not a man should get one, I've been collecting some thoughts here:
https://www.reddit.com/r/postvasectomypain/wiki/ethics