An over-the-top headline and lead sentence set a poor tone for this story about circumcision and the risk of prostate cancer.
But a semblance of balance was recovered in the body of the story, which pointed out some important caveats about the research. Why wait until the last sentence, though, to report on the bottom line impact of the study (which is that it will have no impact at all on medical practice)? Wouldn’t readers be better served seeing that info higher up? There is already evidence that circumcision reduces the risk for infections; the current report adds nothing to the decision-making process.
Parents have a lot to consider when choosing whether to circumcise a newborn son. At this point in time, the risk of prostate cancer isn’t something that should factor into this decision.
Readers may also be interested in this assessment of the study by the surgeon-blogger known as The Skeptical Scalpel.
Although the story didn’t discuss costs, we don’t think the cost of circumcisions is really in question.
The headline for this article — “‘Cutting’ your risk of prostate cancer” — fails on two levels. Not only is the pun quite bad, but the use of the active verb suggests that there is a causal relationship between circumcision and prostate cancer, which is something this observational study can’t prove. Although the text of the story communicated this fact appropriately, it should be reflected in the headline as well.
While absolute risks generally cannot be estimated from case-control studies, extrapolating the 15% relative risk reduction to the 16% lifetime risk for being diagnosed with prostate cancer would suggest that circumcision would be associated with at most a 1% or 2% absolute risk reduction–likely less for clinically important cancers. Of course, the study provides no information on whether circumcision is related to prostate cancer mortality–an important issue given that most prostate cancers are indolent.
Possible harms of circumcision, such as pain, are not discussed.
The story notes some caveats such as possible underreporting of sexually transmitted infections. And it says that the study is “not likely to spur any change in recommendations or medical practice.”
But the argument that “infections” are known to cause cancer is somewhat misleading. The vast majority of this association arise from HPV (cervical, anal, oropharyngeal), HCV (hepatoma), and HIV (lymphoma). However, the Cancer article cites only indirect evidence supporting a link between circumcision, sexually-transmitted infection, and prostate cancer.
Case control studies are notoriously susceptible to bias. At best, findings are hypothesis generating. However, given the biases (arising from poorly or unmeasured confounders, problems measuring and exposures, selecting appropriate control groups), only a dramatically increased or decreased risk is notable. A 15% relative risk reduction is within the range of statistical noise.
We’ll flag this story for an overly bombastic and totally unnecessary lead sentence. Cancer is not the medical equivalent of Lord Voldemort from the Harry Potter books.
The story concludes with a statement attributed to the American Cancer Society suggesting that the findings won’t change medical practice. While this statement is certainly no substitute for an actual conversation with an expert, it’s more context than we see from many similar blog posts about medical studies. We’ll give it a passing grade, though barely.
We’ll rule this one Not Applicable. It didn’t discuss alternative ways to reduce the risk of prostate cancer and that is understandable.
The story didn’t discuss any alternative ways to reduce the risk of prostate cancer. Studies have suggested that chemoprevention with drugs such as finasteride or dutasteride can reduce the risk of prostate cancer by about 25%. Though the benefits of this are controversial, it would provide a ballpark comparison.
The availability of circumcisions is not in question.
The story notes that previous studies have shown a link between circumcision and reduced risk of sexually transmitted infections — the same mechanism that is proposed to explain the association with reduced prostate cancer incidence.
The story is not based on a press release as far as we can tell.