Complication rates after TRUS-guided biopsies in Canada
Posted Feb 05 2010 12:00am
A new report from another group of Canadian researchers has reported a twofold to fourfold increase in the rate of hospital admissions in Ontario within 30 days of the procedure for men receiving a transrectal ultrasound-guided (TRUS-guided) prostate biopsy between 1996 and 2005. This is probably not a finding that will make anyone in Canada very happy.
TRUS-guided biopsy has always been associated with the development of significant morbidity (poor health) in a small proportion of patients. One might assume that there has been a vast increase in the number of TRUS-guided biopsies in Canada over the past 15 years, and that this might help to explain why the morbidity rate associated with this procedure has been rising (at least in Ontario). However, the annual number of TRUS-guided biopsies seems to have been about the same in 1996 as it was in 2005 (having hit a high point in 2001).
Nam et al. carried out a population-based analysis of urological complications associated with TRUS-guided biopsies in the province of Ontario, Canada. Between 1996 and 2005 a total of 75,190 men had such a biopsy. These biopsies were carried out by a relatively small number (437) of specialist physicians (urologists). The authors used hospital and cancer registry databases to estimate the rates of hospital admission and mortality due to urological complications associated with the procedure.
They demonstrated the following results:
33,508/75,190 men who underwent transrectal ultrasound biopsy (44.6 percent) were diagnosed with prostate cancer.
41,682/75,190 men (55.4 percent) did not have prostate cancer.
The overall hospital admission rate for urological complications within 30 days of the procedure was 1,057/75,190 (1.4 percent).
For the men who were diagnosed with cancer,
For the men who did not have cancer,
The majority of hospital admissions (72 percent) were related in some way to an infection.
The overall 30-day mortality rate was 0.09 percent (8.5 men died for every 10,000 men who had a biopsy) but this did not change significantly from 1996 to 2005.
The authors conclude that, “The hospital admission rates for complications following [TRUS-guided] prostate biopsy have increased dramatically during the last 10 years primarily due to an increasing rate of infection related complications.”
Now we should not conclude from this study that prostate biopsy is, in itself, dangerous. There are other reasons why this increase in morbidity may be evident in Ontario. The authors discuss a number of possibilities:
First and foremost, there is no standard method used by urologists (in Canada or anywhere else) to minimize the risk for infections associated with TRUS-guided biopsies.
Second, the number of bacteria that are resistant to standard antibiotics has been rising rapidly over the past 15 years, and this is particularly evident in hospitals (although one study has shown that up to 6 percent of bacteria and other pathogens causing community-acquired urinary tract infections are now resistant to ciprofloxacin).
Third, in 1996 the majority of patients would have received a so-called sextant (six core) biopsy, whereas today patients may commonly have up to 20 or so cores taken at a single biopsy procedure.
Finally, in this study, it was noted that the patients of physicians who performed the highest numbers of biopsy procedures experienced relatively lower risk for hospital admission for complication within 30 days, so once again the skill of the individual physician is important.
It is becoming increasingly evident that it is time for the urology community to adopt a set of standard protocols for prevention of infection and other complications associated with TRUS-guided biopsy. It would also be interesting to know whether there has been a similar pattern of complications in the USA and other countries. In particular, in the USA, prostate biopsies are much more commonly carried out as an “in-office” procedure in the community, and not in an actual hospital, because of the way specialty urology practices are organized in the USA. This in itself may affect the rate of infectious complications associated with TRUS-guided biopsies.
Finally, we should note that the authors themselves point out a number of problems with the way this study was originally carried out. It is clear that similar and more detailed studies are going to be needed to ensure the accuracy of future studies in this field. As just one example of this, based on administrative data alone, it is very difficult to tell exactly why the patients who had been diagnosed with cancer were admitted to the hospital within 30 days of a TRUS-guided biopsy. At least some of them certainly appear to have been admitted for treatment for their prostate cancer — but that could easily include men who actually had complications resulting from the biopsy. In other words, they may have been administratively “coded” as needing treatment for prostate cancer even though they were actually being treated for a complication of a biopsy.