In our recently published article we investigated the purpose of additional samples of the anterior apical region (for exact anatomical location, see figures below) in a repeat biopsy saturation protocol.
Anteriorly located cancer is difficult to detect but has been shown to be important in initial biopsies (1, 2) On one hand, it is often missed by digital rectal examination and TRUS-guided biopsied due to its position farthest from the rectum (3). On the other hand imaging technologies (e.g. magnetic resonance imaging with new up to 7 Tesla machines and multi-parametric protocols) awhich coukld detect them are expensive, time-consuming and user-dependent. Additionally there has not been a final consensus about its use and there may be no nationwide availability in most of the countries in this world.
For our study, we chose the transrectal approach. It allows easier access via a natural orifice in contrast to e.g. the transperineal approach (4, 5). We could show that the complication rate was equal with lower efforts.
We achieved an overall cancer detection rate of 45% with exclusive cancer detection rate of almost 10% in the anterior apical region. Overall involvement of the anterior apical region was found in 42% of all detected cases. In comparison to the transition zone, which should now be sampled in repeat biopsies, we found a five-fold higher cancer detection rate. We mostly detected low risk prostate cancer according to the D’Amico risk stratification of prostate cancer, but several were also of intermediate risk. We also looked for eventual upgrading in the risk classification by these cores and we found it in 3% of all patients. Clinical practice has shown all of us that low-risk prostate cancer has very limited potential to become systemic. Although recent molecular and genetic findings (6) suggest that even a low-risk carcinoma focus with as Gleason score of 3 may be responsible for systemic disease. Thus, no final scientific statement about definite prognosis of prostate cancer is now possible and we cannot finally determine the one patient in whom we can consider the cancer as safe and not life-threatening.
With regard to the high exclusive cancer detection rate and the discovery of several intermediate-risk cancers in our present series, implementation of anterior apically directed cores in least repeat biopsy protocols could be considered.
The schematic drawing of the prostate in Figure 1 shows a median sagittal plane at level of the urethra. The dotted red line indicates the level of section shown in Figure 2, the dashed red line indicates the level of section shown in Figure 3. The numbers 1-14 indicate the location of each core in each zone on one side of the prostate.
References:
1. Moussa AS, Meshref A, Schoenfield L, Masoud A, Abdel-Rahman S, Li J, et al. Importance of additional “extreme” anterior apical needle biopsies in the initial detection of prostate cancer. Urology [Internet]. 2010 May;1034–9.
2. Koppie TM, Bianco FJ, Kuroiwa K, Reuter VE, Guillonneau B, Eastham J a, et al. The clinical features of anterior prostate cancers. BJU Int [Internet]. 2006 Dec;1167–71.
3. Numao N, Kawakami S, Sakura M, Yoshida S, Koga F, Saito K, et al. Characteristics and clinical significance of prostate cancers missed by initial transrectal 12-core biopsy. BJU Int [Internet]. 2012 Mar;665–71.
4. Pepe P, Dibenedetto G, Pennisi M, Fraggetta F, Colecchia M, Aragona F. Detection Rate of Anterior Prostate Cancer in 226 Patients Submitted to Initial and Repeat Transperineal Biopsy. Urol Int [Internet]. 2014 Apr 26;3–6.
5. Danforth TL, Chevli KK, Baumann L, Duff M. Low incidence of prostate cancer identified in the transition and anterior zones with transperineal biopsy. Res reports Urol [Internet]. 2012;71–6.
6. Haffner MC, Mosbruger T, Esopi DM, Fedor H, Heaphy CM, Walker DA, et al. Tracking the clonal origin of lethal prostate cancer. J Clin Invest. 2013;4918–22.
Written by:
Maximilian Seles, MD
Department of Urology, Medical University of Graz, Austria.