Undescended testis and future risks of testicular cancer and infertility from a large Australian population cohort.

This article published in Lancet Child Adolesc Health discusses the risk of testicular cancer and infertility associated with hypospadias and undescended testis (UDT). I decided to review it because It was featured in the New York Times. I will only focus on the part of the study pertaining to UDT.

What we currently know

For an otherwise healthy child with an UDT, the American Urologic Association recommends orchiopexy between the ages of 6 and 18 for the following reasons:

  1. They won’t remember the surgery
  2. Will give them normal looking anatomy (cosmesis and comfort)
  3. Could decrease the risk of testicular cancer
  4. Could increase the chances of fathering children.

It is worth pointing out that the risk for both infertility and cancer is low, so the main reason to perform surgery is for cosmesis and comfort.  Acknowledging this is especially important when the child has serious comorbidities.

The numbers I use to counsel families come from the study by Patterson et al published in 2007 on the NEJM: the study found that the risk of testicular cancer was 0.3% and 1% for orchiopexies done before or after age 13 years, respectively.

 

What the new study found

These are the main findings from the new Australian study:

  • 7,499 patients with UDT
    • 27 had testicular cancer (0.36%),
    • 127 used Assisted reproductive technologies (1.7%)
    • 2016 fathered children (27%)
  • 341,000 controls
    • 476 had testicular cancer (0.14%)
    • 2,529 used ART (0.7%)
    • 107,006 fathered children (31%)
UDT Control
Testicular cancer 0.36% 0.14%
ART 1.7% 0.7%
Fathered children 27% 31%

There are 2 ways to analyze the results of this study:

Looking at the big picture

The common sense way of interpreting this data is recognizing that UDT have a minuscule risk for both infertility and cancer. The risk is small regardless of whether surgery is done and of the timing of surgery. It would then be logical to recommend surgery for healthy children mostly for cosmesis and comfort and against surgery for children with other problems where cosmesis and comfort would not be a priority.

Nitpicking statistics

The other way to analyze the study is to focus on the odds/hazard ratios and noticing how the risk of testicular cancer and infertility is 2-5 times higher in patients with UDT, and how the timing of surgery can affect the risk in a statistically significant fashion (but not in any clinically significant way). Doctors and the news can then spook parents with the “C” word mostly unnecessarily.

This approach leads to surgery being recommended for UDT in unhealthy children unlikely to benefit from it.

From only studying 27 cases of testicular cancer, the study concluded that the older the child is at the time of his orchiopexy, the greater the cancer risk. Of the 27 patients with testicular cancer, 24 were older than 3 years at the time of the orchiopexy, just like most of the boys who did not get cancer (mean age at the time of orchiopexy in the study was 5.6 years). A big picture look at this claim allows you to dismiss it as clinically irrelevant. On the other hand, the nitpick approach will have you believe that we should rush patients to the operating room ASAP.

 

Conclusion

The main reason for recommending surgery in cases of UDT is cosmesis and comfort. Emphasizing the small risks of testicular cancer and infertility to justify surgery is akin to fearmongering.

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