UROLOGICAL SURVEY
Imaging
Focal prostatic atrophy: mimicry of prostatic cancer on TRUS and 3D-MRSI studies
Prando A, Billis A
Department of Radiology, Hospital Vera Cruz and Department of Anatomic Pathology, School of Medicine, Campinas, SP, Brazil
Abdom Imaging. 2008 (published online 4 march 2008), ISSN: 1432-0509
OBJECTIVE: It is well known that histologically focal prostatic atrophy (FPA) is one of the most frequent mimics of prostatic adenocarcinoma. The purpose of our study was to show that FPA may also simulate prostate cancer on transrectal ultrasound studies (TRUS) and on 3D-magnetic resonance spectroscopic imaging of the prostate (3D-MRSI).
MATERIALS AND METHODS: From 2004 to 2006, 625 men suspected of prostate cancer, underwent TRUS guided biopsy (n = 513, group I) or TRUS-guided biopsy directed with 3D-MRSI of the prostate (n = 142, group II). The latter group was formed only by patients with elevated PSA levels and prior negative prostate biopsies. All sites showing FPA on histopathologic analysis were correlated with findings observed on gray scale and color Doppler-TRUS studies or on 3D-MRSI of the prostate.
RESULTS: From a total of 513 patients biopsied and studied by gray scale and color Doppler-TRUS(Group I) , 48 patients (9.3%) presented histological diagnosis of FPA associated with sonographic abnormalities in the peripheral zone of the prostate. Thirty-two patients presented hypoechoic nodules with absent flow and 16 patients had hypoechoic nodules with increased flow. From a total of 142 patients submitted to TRUS-guided biopsy directed with 3D-MRSI (Group II), 16 (11.2%) presented histological diagnosis of FPA associated with abnormalities strongly suspicious for prostate cancer on conventional MRI and/or on 3D-MRSI. These abnormalities were: focal area of low signal intensity on T2-w image or clusters of voxels with choline + creatine/ citrate ratio above 3 SDs.
CONCLUSION: Similarly to the histopathologic findings focal prostatic atrophy may mimic cancer on gray-scale and color Doppler-TRUS studies and on 3D-MRSI studies. Radiologists should be aware of this entity which together with prostatitis, represent an important cause of false-positive result on prostatic biopsy directed with endorectal MRSI (11.2%).
Editorial Comment
Prostatic atrophy is one of the most frequent mimics of prostatic adenocarcinoma. There are still controversies regarding the causal linkage of FPA to the prostate cancer and to other pre-neoplastic lesions. On conventional and color Doppler transrectal ultrasound and on magnetic resonance spectroscopic imaging studies (MRSI), FPA may also simulate prostate cancer. The vast majority of our cases that simulate prostate cancer were related to sub-type hyperplastic prostatic atrophy. We might speculate why FPA manifests as false-positive MRSI findings: in the hyperplastic sub-type, the number of cellular membranes are increased. This could explain the elevation of choline level without modification of the polyamine level. It has been shown that there is a positive and significant association between extent of FPA in biopsies and serum total or free PSA elevation. For this reason, pathologists should include the presence of FPA in the pathology report of a prostatic biopsy, particularly in those patients with absence of cancer. When extensive FPA is the only finding in patients with several negative prostatic biopsies, this lesion may be the source for PSA elevation.
Dr. Adilson Prando
Chief, Department of Radiology and
Diagnostic Imaging
Vera Cruz Hospital
Campinas, São Paulo, Brazil
E-mail: aprando@mpc.com.br
The 20-core prostate biopsy protocol--a new gold standard?
Ravery V, Dominique S, Panhard X, Toublanc M, Boccon-Gibod L, Boccon-Gibod L
Department of Urology, Bichat Hospital, Paris, France
J Urol. 2008; 179: 504-7
PURPOSE: We investigated the ability of a 20-core prostate biopsy protocol to enhance the prostate cancer diagnosis rate.
MATERIALS AND METHODS: We compared the diagnosis rate of prostate biopsies in 2 groups of consecutive patients, including group 1-10 cores and group 2-20 cores. The prostate specific antigen range in the 2 groups was 3 to 30 ng/mL and biopsies were performed because of increased prostate specific antigen (more than 3 ng/mL) and/or abnormal digital rectal examination. To analyze the results we divided each group into 3 subgroups according to prostate specific antigen, including group 1-3 to less than 6 ng/mL, group 2-6 or greater to less than 10 ng/mL and group 3-10 or greater to up to 30 ng/mL. Multivariate analysis was performed to assess the difference in the diagnosis rate among the subgroups according to the number of cores taken.
RESULTS: The percent of positive biopsies was 39.7% in group 1 and 51.7% in group 2. Multivariate analysis confirmed that the number of biopsies taken was a factor that independently and significantly correlated with the prostate cancer diagnosis. The 20-core biopsy protocol was more efficient than the 10-core protocol in the 3 subgroups with 47.2% vs. 28.1% of patients diagnosed in group 1 (OR 3.26, p = 0.001), 40.5% vs. 36.1% in group 2 (OR 2.37, p = 0.009) and 69.8% vs. 39.7% in group 3 (OR 2.01, p = 0.015).
CONCLUSIONS: The 20-core biopsy protocol was more efficient than the 10-core biopsy protocol, especially in patients with prostate specific antigen between 3 and 6 ng/mL. Nevertheless, it is mandatory to confirm whether detected tumors are clinically significant on pathological examination of the radical prostatectomy specimens.
Editorial Comment
The authors of this manuscript demonstrated that the 20-core biopsy scheme was more efficient for diagnosing prostate cancer than the 10-core biopsy scheme in 3 distinct subgroups of PSA levels .Unfortunately they did not evaluate these two different protocols according to the patient age and prostate volume. As we know, prostate volume is a relevant variable in the planning of the optimal number of cores in the first scheme of biopsy. In our experience, there is no magic number of cores to be taken that could be adequate for all patients. We think that the location from where these cores were taken is more important than the total number of cores. Several reports in the literature has been shown that for prostate less than 40 cc, a scheme with 12 cores is usually adequate. However, this scheme is usually inadequate for prostate larger than 80 cc. Another important issue to consider is whether additional cores are or are not routinely obtained from suspicious hypoechoic lesion or area with clear abnormal flow on color Doppler examination. In a review of 589 consecutive TRUS-guided biopsy , where we prospectively removed 12 cores from prostates < than 40 cc; 14 cores from prostates with 41-60 cc; 16 cores from prostates with 61-80 cc and 18 cores from prostates > than 80 cc), there was no proportional increase in the prostate cancer detection rate. The two best results were obtained with 12 cores/ < 40 cc (44.8%) and 16 cores/ 61-80 cc) = 36.5%. The detection rate obtained with the scheme with 18 cores/ > 80 cc was only 29%. Additional cores obtained in all patients from suspicious lesions on gray-scale and/or color-Doppler were not included in these results. The presence of suspicious hypoechoic was not statistically significant but the use of color Doppler increased the overall diagnosis rate in 8% of patients (isoechoic cancer). Color-Doppler ultrasound was particularly useful for the detection of cancer in patients with larger glands.
Dr. Adilson Prando
Chief, Department of Radiology and
Diagnostic Imaging
Vera Cruz Hospital
Campinas, São Paulo, Brazil
E-mail: aprando@mpc.com.br
Publication Dates
-
Publication in this collection
06 Oct 2008 -
Date of issue
Mar 2008
