|Year : 2013 | Volume
| Issue : 2 | Page : 163-169
The role of transrectal ultrasound-guided biopsy in diagnosis of prostate cancer
Basma A El-Moniem Dessouky1, Waleed A El-Fattah1, Samer T Gaffer2
1 Department of Radiodiagnosis, Faculty of Medicine, Menoufia University, Menoufia, Egypt
2 Department of Radiodiagnosis, El-Gomheria Hospital, Cairo, Egypt
|Date of Submission||26-Mar-2013|
|Date of Acceptance||04-Jun-2013|
|Date of Web Publication||31-Jan-2014|
Samer T Gaffer
Gamal Abd El-Naser Street, Sheibien El-kom, Menoufia
Source of Support: None, Conflict of Interest: None
The aim of this study was to evaluate the role of transrectal ultrasonography (TRUS)-guided biopsy in the detection of prostate cancer in patients on the basis of elevated prostate-specific antigen levels and abnormal digital rectal examination (DRE) results.
The TRUS-guided biopsy technique was regarded as the golden standard method for diagnosis of prostate cancer. This study aimed to identify an appropriate prostate biopsy protocol for the detection of prostate cancer.
Materials and methods
This study included 30 patients having symptoms suggestive of prostatic diseases. All these patients were subjected to DRE, serum prostate-specific antigen testing, transabdominal ultrasound examination and TRUS, as well as biopsy taking.
Among the 30 patients studied, final diagnosis by TRUS-guided biopsy revealed benign prostatic hyperplasia in 16 patients (53.3%), which was the most common pathology, precancerous lesions in seven patients, prostatitis in four patients (13.3%), and prostatic adenocarcinoma in three patients (10%). Among the patients with precancerous lesions, five (16.7%) had prostatic intraepithelial neoplasia and two (6.7%) had atypical adenomatous hyperplasia.
Correlation of prostate-specific antigen levels and findings from DRE and TRUS images with biopsy results is considered the most useful method to improve sensitivity of prostate cancer detection.
Keywords: Biopsy, diagnosis, prostate cancer, ultrasound
|How to cite this article:|
El-Moniem Dessouky BA, El-Fattah WA, Gaffer ST. The role of transrectal ultrasound-guided biopsy in diagnosis of prostate cancer. Menoufia Med J 2013;26:163-9
|How to cite this URL:|
El-Moniem Dessouky BA, El-Fattah WA, Gaffer ST. The role of transrectal ultrasound-guided biopsy in diagnosis of prostate cancer. Menoufia Med J [serial online] 2013 [cited 2020 Feb 27];26:163-9. Available from: http://www.mmj.eg.net/text.asp?2013/26/2/163/126155
| Introduction|| |
Prostate cancer is the most common visceral malignant neoplasm among men, now accounting for one-third of all such cancers. Prostate cancer remains a major healthcare concern and a significant cause of morbidity and mortality  .
Transrectal ultrasonography (TRUS) is the most commonly used modality for imaging the prostate gland. It enables accurate determination of prostate size. When a cancer is visualized by ultrasonography, it is usually hypoechoic relative to normal tissue. Moreover, the majority of hypoechoic foci detected by TRUS are not malignant; therefore, both its sensitivity and specificity are low. TRUS is mainly used to guide prostate biopsies ,, .
TRUS-guided biopsy is the most reliable method, at present, for accurate sampling of prostatic tissue in men considered at high risk for prostatic cancer. On the basis of digital rectal examination (DRE) and prostate-specific antigen (PSA) findings, the TRUS-guided biopsy technique has become the accepted standard for prostate cancer diagnosis worldwide ,,,, .
Although TRUS-guided prostate biopsy is relatively quick to perform and is carried out under local anesthesia, it is nevertheless an invasive procedure, which may cause significant anxiety and pain in patients. In addition, it may potentially result in several complications including: epididymitis, prostatitis septicemia, hematuria, haematospermia, and rectal bleeding , .
| Materials and methods|| |
This study was carried out on 30 patients over a period of 10 months starting from 1 December 2011 to 1 October 2012. The patients were referred with urinary symptoms suggestive of prostatic disease, diagnosed using different ultrasound machines.
This study included patients with elevated PSA levels (>4 ng/ml) and abnormal findings on DRE. Informed consent was obtained from all participants, and a full explanation was given to them about the procedure.
All patients were subjected to DRE, serum PSA testing, transabdominal ultrasound examination and TRUS, as well as biopsy taking. Before the procedure, the patients were prophylactically treated with different antibiotics to protect them against infection; they also underwent rectal enema to empty the rectal canal to obtain clear images, and different methods of anesthesia were used to alleviate pain and discomfort during the procedure.
A biplane probe (5-8 MHz range) with a combination of end-viewing and side-viewing transducers was used. Ultrasound gel was applied over a latex condom applied onto the probe. All patients were examined in the left lateral decubitus position because it is well tolerated. A full urinary bladder helped in better visualization of the gland.
The prostate was imaged in both axial and sagittal planes with assessment of volume, echogenicity, surface, calcification, and the presence of nodules. Each nodule was assessed for size, location in the gland, morphology, echogenicity, margin, and extent. Color Doppler ultrasonography was then performed to assess color mapping of the nodules and the surrounding prostate tissue.
Sampling of the prostate was performed either in the sagittal or in the axial plane. Biopsies were obtained using different types of needles of different lengths, and they were as follows: semiautomatic prostatic biopsy needles (18 G × 20 cm or 18 G × 25 cm), automatic biopsy needles (18 G × 20 cm or 18 G × 25 cm), and a needle gun or manual biopsy needle (18 G × 20 cm). Different biopsy protocols were used; the most commonly used protocol was the extended core biopsy protocol (11-15 cores). After biopsy samples were obtained, they were persevered in 38% formaldehyde solution and were sent to the pathology centre for cytological analysis.
The grade (degree of aggressiveness) of prostate cancer was evaluated on the basis of the Gleason score. The pathologist examined two tissue samples taken from different areas of the prostate and assigned each sample a score between 1 and 5. The sum of the two scores was the Gleason score. Few complications were observed after the procedure and controlled.
| Results|| |
The age of the studied patients ranged from 50 to 82 years, with a mean age of 68.3 years (SD 6.1). The majority of patients [28 patients (95%)] were older than 60 years [Table 1]. Among the 30 patients, the most commonly presenting symptoms were obstructive and irritative lower urinary tract symptoms [22 patients (73.3%)], followed by acute urine retention [five patients (16.7%)] and hematuria [three patients (13.3%)].
DRE was performedfor all patients in this study to exclude the presence of palpable nodules, to palpate the consistency of the prostate, and to palpate the surface of the prostate. Eleven palpable nodules (36%) were present, which were proven by biopsy to be benign prostatic hyperplasia (BPH) in four patients, prostatic adenocarcinoma in three patients, prostatitis in two patients, and prostatic intraepithelial neoplasia (PIN) in two patients. Consistency of the prostate was soft in four patients with prostatitis (13.3%), hard in three patients with prostatic adenocarcinoma (10.7%), and firm in 23 patients (76%) including 16 patients with BPH, five patients with PIN, and two patients (80%) with atypical adenomatous hyperplasia. The surface of the prostate was irregular in nine patients (30%), including four patients with BPH, two patients with prostatic adenocarcinoma, two patients with prostatitis, and one patient with PIN; the surface of the prostate was smooth in the remaining 21 patients (70%; [Table 2]).
Total PSA (tPSA) level was elevated in all patients (>4 ng/ml). It ranged from 10 to 20 ng/ml in 22 patients (73.3%), including 14 patients (46.7%) with BPH, four patients with prostatitis (13.3%), and four patients with PIN. In contrast, it ranged from 20 to 50 ng/ml in four patients (13.3%), including two patients with BPH, one patient with PIN, and one patient with prostatic adenocarcinoma, and was more than 100 ng/ml in two patients (6.7%) with prostatic adenocarcinoma [Table 3].
|Table 3: Total prostate-specific antigen level in the 30 studied patients|
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The volume of the prostate ranged from 25 to 120 cm 3 , with mean of 72.5 cm 3 (SD 26.8). Twenty patients (66.7%), including 16 patients with BPH (80%), three patients with prostatic adenocarcinoma (15%), and one patient with PIN (5%), had markedly enlarged prostates, whose volumes ranged from 61 to 120 cm 3 . TRUS showed hypoechoic focal lesions in nine patients (30%). On color and power Doppler ultrasonography, seven focal lesions were observed to have increased vascularity (63.3%), one had normal vascularity (9.1%), and two had hypovascularity (18.4%).
Different needles were used for biopsies. The most commonly used needles were automatic biopsy needles (18 G × 25 cm) because they are easy to use and long enough to allow a wide range of biopsy levels; in addition, they pierce the prostatic capsule after firing, which causes a decrease in pain perception; these needles were used in 18 patients (60%). Different biopsy protocols were used in this study; the most effective 11-15 biopsy cores in 20 patients (76%) with good results and there was no need to repeat biopsy [Table 4]. Sextant biopsy was noteffective and repeat biopsies were required in four patients because of an insufficient amount of biopsy sample. In this study, the majority of biopsies revealed BPH [16 patients (53.3%)], whereas the minority revealed prostatitis (four patients) and prostatic adenosis (two patients). Precancerous lesions were observed in seven patients (five with PIN and two with atypical adenomatous hyperplasia), whereas prostatic adenocarcinoma was observed in only three patients [Table 5]. Few complication occurred in some patients, most of which were self-limiting and controllable. The most frequent complication was dull aching pain in the perineum in 15 patients (50%), which was controlled using simple analgesics. Gross hematuria occurred in five patients (16.7%). Rectal bleeding occurred in two patients (6.7%). Hematospermia was observed in one patient. All of these hemorrhagic complications were controlled using hemostatic drugs. The least reported complication was infection, which was reported in one patient and was prevented in the other patients by administration of strong antibiotics after the procedure. Vasovagal attacks were reported in two patients and controlled using diazepam.
| Discussion|| |
TRUS has traditionally been considered as the pivotal imaging test for the prostate, providing clinically important information as regards benign and malignant conditions  . Before the widespread availability of diagnostic tools enabling early detection of the disease, such as DRE, TRUS, and PSA measurement, prostate cancer was frequently diagnosed at an advanced stage, leading to patient mortality in a shorter duration time  .
In this study, the age of the patients ranged from 58 to 82 years. The majority of patients in this study were above the age of 60 years [28 patients (95%)]. This was because of the high incidence of prostatic diseases (including prostate cancer) during old age, as reported by Jemal et al.  .
Abnormal DRE results that led to the suspicion of prostate cancer were reported in 11 patients. In the study by Aus et al.  , prostate cancer was detected on the basis of suspicious DRE results in 18% of patients; they reported that suspicious DRE results are an absolute indication for prostate biopsy.
The PSA level was elevated in all patients of this study (>4 ng/ml). Thompson et al.  and Schroder et al.  reported that, although a serum tPSA level of more than 4 ng/ml can imply the presence of prostate cancer, patients with BPH and inflammatory prostate disorders can also present with increased serum tPSA levels. The lack of specificity of serum tPSA measurements in prostate cancer screening has inevitably led to further efforts using the PSA ratio (free PSA to tPSA), which is more specific and decreases the number of biopsies taken.
In this study the volume of the prostate ranged from 25 to 120 cm 3 , with a mean of 72.5 cm 3 . Twenty patients (66.7%) had markedly enlarged prostates, including 16 patients with BPH (80%), three patients with prostatic adenocarcinoma (15%), and one patient with PIN (5%); their volumes ranged from 61 to 120 cm 3 . Chung et al.  reported that the volume of the prostate was enlarged in BPH and prostate cancer, but it was a good indicator for prostate cancer.
In the current study, TRUS of focal lesions showed 11 hypoechoic focal lesions [Figure 1]. Apple et al.  reported variability in the ultrasonic appearance of tumors; TRUS alone performs poorly for prostate cancer identification. Although some prostatic tumors can be visualized as hypoechoic areas that are distinguishable from the normal homogenous isoechoic parenchyma, most hypoechoic lesions are not cancerous. Moreover, many early stage cancers are isoechoic and not distinguishable from surrounding benign tissue.
Biopsies were taken using three types of needles of different lengths, and they are as follows: semiautomatic prostatic biopsy needles (18 G × 20 cm or 18 G × 25 cm) in five patients (16.7%), automatic biopsy needles (18 G × 20 cm or 18 G × 25 cm) in 22 patients (76.6%), and a needle gun or manual biopsy needles (18 G × 20 cm) in two patients (6.7%). According to Kamoi et al.  , 18 G needles were used, and the tips of the needles were etched with small ridges to increase their echogenicity.
Four biopsy protocols were used in this study [Figure 1],[Figure 2],[Figure 3] and [Figure 4]: the original sextant biopsy technique was performed in five patients (16.7%), the modified sextant technique in two patients (6.7%), 11-core biopsies in 11 patients (36.7%), and 15-core biopsies in 12 patients (40%). In this study, it was noted that the more the number of core biopsies obtained, the more accurate were the results and the lesser was the need to repeat the biopsy. Hence, the best results were obtained using the 15-core biopsy protocol, which was used in 12 patients. Repeat biopsies were carried out in four patients (23.4%) from the sextant biopsy protocol group. One of the repeated biopsies revealed PIN (a precancerous lesion), which highlights the need to increase the number of core biopsies so as to not miss any lesion. Djavan et al.  reported that sextant biopsies do not detect all clinically significant cancers, and efforts have been made to improve the sextant protocol by adding other biopsies and/or changing biopsy positions, so that the reliability of systematic biopsy for cancer detection relates to the number of cores, as well as to their placement. Using a systematic biopsy to sample all areas of the prostate regardless of the presence of hypoechoic lesions became strongly recommended and preferred by many urologists rather than the old method of searching for and biopsying each single lesions in addition to carrying out systematic biopsies.
In accordance with the findings of Eskew et al.  , Presti et al.  and Babaian et al.  reported that the reliability of systematic biopsy for cancer detection is related to the number of cores, as well as to their placement. It is probable that six biopsies are enough to sample most of the prostate, even if the standard sextant biopsy scheme does not appear to be the best method for sampling the peripheral zone of the prostate and does not sample the transitional and anterior zones. The most frequently used biopsy protocol was the sextant protocol; shifting of the sextant biopsies more laterally was proposed to better sample the peripheral zone where most of the cancers are located. Naughton et al.  reported that a single set of sextant biopsies may miss clinically detectable prostate cancer in 15-34% of men and advised to increase the number of core biopsies taken as a 37% increase in cancer detection was observed when 11 and 15 cores were used.
In the current study, complications occurred, most of which were controllable and self-limited. The most frequent complication was dull aching pain in the perineum in 15 patients (50%), which was controlled using simple analgesics. Gross hematuria was observed in five patients (16.7%), rectal bleeding in two patients (6.7%), and hematospermia in one patient (3.3%). All of these hemorrhagic complications were controlled using hemostatic drugs. Infections occurred in five patients (16.7%) and were controlled by administration of strong antibiotics after the procedure. Vasovagal attacks were reported in two patients (6.7%) and controlled using diazepam. In the study by Ihezue et al.  , transrectal prostatic biopsy revealed 1-2% major complications (sepsis, bleeding, or other complications requiring hospital admission). Minor complications were also reported, with the following rates: hematuria, 1-84%; rectal bleeding, 37%; hematospermia, 1-28%; vasovagal episodes, 0-5%; infective complications, 1-4%.
| Conclusion|| |
Correlating the PSA ratio (free PSA to tPSA) with findings from DRE and TRUS was considered to be the most useful method to improve the sensitivity of prostate cancer detection.
The standard sextant biopsy scheme did not appear to be the best method of sampling the peripheral zone of the prostate and does not sample the transitional zone. Hence, the reliability of systematic biopsy for cancer detection is related to the number of cores, as well as their placement. Increasing the number of cores taken led to more accurate detection of prostate cancer, negating the need to repeat the biopsy.
TRUS-guided prostate biopsy is generally considered safe and is commonly performed in an outpatient setting with minor controllable complications.
| Acknowledgements|| |
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]