I am a little confused over a point made in your latest Best Tests (Oct, 2012). I am sure I heard Dr Costello tell
us on several occasions at the GP CME conference in Dunedin in August 2012, that 6 - 12 monthly DRE was still necessary
in prostate cancer follow-up, no matter what the grade as there is a risk of the cancer undifferentiating which makes
Dr Costello provided expert guidance in the development of our article: "Following
up prostate cancer in primary care", Best Tests (Oct, 2012). Most guidelines recommend that routine digital rectal
examination (DRE) is generally not necessary in men where regular PSA testing indicates no change from baseline (but
would be indicated if change occurred). DRE is not very useful after radical prostatectomy because early local recurrence
is not usually able to be felt. After radical radiotherapy, it may be difficult to distinguish between scar tissue
and residual or recurrent cancer. Therefore, DRE is regarded as being of limited clinical value in these situations.
The exception is in men who have had high grade prostate cancers, i.e. Gleasons 9 and 10, where DRE may be of more
value as PSA may not be representative. This is an area of some disagreement, however, and guidelines do vary.
There is some evidence that adding DRE to regular PSA testing for a small subset of patients with poorly differentiated,
high Gleason score prostate cancers may reduce prostate cancer related death.1 Routine DRE is not, however,
necessary as part of follow up in all men with prostate cancer. It is recognised that poorly differentiated prostate
cells leak PSA at a lower rate than well differentiated cancer cells. De-differentiation (the change of cancer cells
to a poorly differentiated state) may lead to a slower rise in PSA level than the disease level might indicate. There
have been cases studies illustrating the progression to metastatic disease without an elevation in PSA level. It is
estimated that the incidence of developing metastatic prostate cancer following radical prostatectomy, without a rise
in PSA, is of the order of 2.3 - 2.6%.2,3 It is also recognised that small cell prostatic cancer is not associated
with PSA expression.
It should be noted that there is a small potential for radical radiotherapy to induce rectal cancer after a period
of years, therefore, there should be increased vigilance for this.
New Zealand-specific guidelines are likely to be produced soon as the Prostate Cancer Taskforce has now released a
working consultation document, so recommendations may change in the future.
ACKNOWLEDGEMENT: Thank you to Dr Shaun Costello, Radiation
Oncologist, Clinical Director Southern Cancer Network for expert guidance in developing this response.
- Hattangadi J, Chen M, D'Amico A. Early detection of high-grade prostate cancer using digital rectal examination
(DRE) in men with a prostate-specific antigen level of <2.5 ng/mL and the risk of death. BJU Int 2012;[Epub ahead
- Leibman B, Dillioglugil O, Wheeler T, Scardino T. Distant metastasis after radical prostatectomy in patients without
an elevated serum prostate specific antigen level. Cancer 1995;76(12):2530-4.
- Oefelein M, Smith N, Carter M, et al. The incidence of prostate cancer progression with undetectable serum prostate
specific antigen in a series of 394 radical prostatectomies. J Urol 1995;154(6):2128-31.
- Heterophile antibody vs EBV serology testing for glandular fever: Best Tests (Oct 2012)