CLINICAL UPDATE
Risks in( not) diagnosing prostate cancer
Various colleges and government agencies seem to provide mixed messages on prostate cancer detection. When it comes to biopsies, small changes in methods have the potential to decrease negative biopsies and improve safety.
Screening recommendations and use varies
The American Urological Association has just downgraded recommendations for prostate cancer screening to align more with the more conservative U. S. Preventive Services Task Force( USPSTF), which says the harms outweigh the benefits for prostate cancer screening. This policy change has to be seen in the light of the Urologists in the USA being very aggressive on prostate cancer screening for many years. At the same time, Prof Bruce Armstong( Director of Australian Agency for Health and Welfare), who has long opposed prostate cancer screening, changed his mind and now believes benefits are likely.
The European prostate screening study group from Goteborg( Sweden) had the most compelling evidence for a benefit from prostate cancer screening with similar numbers needed to treat as breast and colon cancer screening trials. Interestingly Australia, like Sweden, has one of the world’ s highest incidences and mortality rates of prostate cancer. There are no studies of prostate cancer screening in an Australian population.
This uncertainty leads to disparate practices regarding PSA testing amongst Australian doctors – not acting on an elevated result is risky.
The Goteburg study used a PSA cutoff of 3.2 ng / ml to suggest biopsy. PSAs above this level should at least prompt discussion of the risk of prostate cancer with the patient. New parameters such as free to total ratio and proPSA can be added to PSA in online calculators to refine an individual’ s risk of a biopsy diagnosing cancer( http:// deb. uthscsa. edu / URORiskCalc / Pages / calcs. jsp). proPSA is available via Clinipath as a PHI-prostate health index test that is not MBS-rebateable.
MRI use
Currently, MRI use in diagnosis of prostate cancer involves targeting an abnormal area, and reducing the number of biopsies required. The negative predictive value of MRI’ s is such that it will not replace biopsy yet but it can give useful information regarding staging and reassure patients in the setting of a negative biopsy with a rising PSA. Unfortunately there is no rebate for prostate
� Prostate cancer MRIs.
MRI( which costs patients $ 500-700).
Prostate biopsy
Prostate biopsy is done with a transrectal ultrasound probe to image the gland( TRUS / PB). The biopsy needle passes through either the rectal mucosa( transrectal) or the skin( transperineal). The risk of infectious complications following TRUS / PB has increased up to fourfold and up to 10 % of patients admitted with post biopsy septicemia require ICU admission
( with rare fatalities). This increasing risk is largely due to the increasing prevalence of fluoroquinolone resistance. Predictive risk factors include frequent antibiotics usage, frequent travel to SE Asia( livestock antibiotic feeding), diabetes, and increased number of biopsies taken.
One effective strategy to reduce infectious complications was pioneered locally at Hollywood Hospital with the use of betadine rectal suppositories at the time of biopsy. A randomised trial has just been published from Canada demonstrating a significant risk reduction with this technique.
In areas of high fluoroquinolone resistance, faecal cultures can identify antibiotic resistance and prompt adjusted prophylaxis in individual cases, while the same strategy
By Clinical A / Prof Justin Vivian,
Urologist.
Tel 9382 4999
can be used in individuals at risk( immune suppressed, frequent travelers, or prolonged antibiotic users).
Avoiding the contaminated rectum and performing transperineal biopsies is another solution. Reported sepsis rates of 0.2 % following transperineal biopsy compare favourably to the 2.8 % for transrectal biopsy( with similar prostate cancer detection rates). The drop in septic complications following transperineal biopsy is more significant as these patients had more biopsies( 14) than the transrectal group( 10).
References Sanders et al, ANZ J Surg 83( 2013) 246-248, Infectionrelated hospital admissions after transrectal biopsy of the prostate. Tsivian et al, Urology 2013 May 19. pii: S0090- 4295( 13) 00372-5. doi: 10.1016 / j. urology. 2013.01.071. Lawrentschuk Nathan, ANZ J Surg( 2013) 197-198, The role of magnetic resonance imaging in prostate cancer Barentsz JO et al, ESUR prostate MR guidelines Hugosson J, Carlsson S, Aus G, et al. Mortality results from the Göteborg randomised population-based prostatecancer screening trial. Lancet Oncol 2010; 11: 725-732. Andriole GL, Crawford ED, Grubb RL 3rd, et al. Prostate cancer screening in the randomized Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial: mortality results after 13 years of follow-up. J Natl Cancer Inst 2012; 104: 125-132. Schröder FH, Hugosson J, Roobol MJ, et al. Prostate-cancer mortality at 11 years of follow-up. N Engl J Med 2012; 366: 981-990
Declaration: The author treats prostate cancer; no competing interests identified.
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