‘Cutting’ your risk of prostate cancer

Does the story adequately discuss the costs of the intervention?

Not Applicable

Although the story didn’t discuss costs, we don’t think the cost of circumcisions is really in question.

Does the story adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

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.

Does the story adequately explain/quantify the harms of the intervention?

Not Satisfactory

Possible harms of circumcision, such as pain, are not discussed.

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

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.

Does the story commit disease-mongering?

Not Satisfactory

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.

Does the story use independent sources and identify conflicts of interest?

Satisfactory

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.

Does the story compare the new approach with existing alternatives?

Not Applicable

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.

Does the story establish the availability of the treatment/test/product/procedure?

Not Applicable

The availability of circumcisions is not in question.

Does the story establish the true novelty of the approach?

Satisfactory

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.

Does the story appear to rely solely or largely on a news release?

Satisfactory

The story is not based on a press release as far as we can tell.