Does it need to Take Digitally Targeted Biopsies Additionally to TRUS Guided 12- Core Systematic Prostate Biopsies? A Single Center Prospective Clinical Study

Ali Erol1, Sarp Korcan Keskin1* and Huseyin Akyildiz2

Urology, Istanbul, Turkey, Tel: +905359444400; Email: urologum@gmail.com TRUS guided systematic biopsies.

The Results:

detected one cancer out of 2 in this group.

guided biopsies did not increase the detection rate of systematic biopsies in this group.

undifferentiated tumors.

Keywords: Prostate cancer; Tumors; 12-core Systematic biopsies Does it need to Take Digitally Targeted Biopsies Additionally to TRUS Guided 12- Core Systematic Prostate Biopsies? A Single Center Prospective Clinical Study.

J Urol Nephrol

Abbreviations: TRUSG: Transrectal Ultrasound Guided; PSA: Prostate Specific Antigen; DRE: Digital Rectal Examination.

Introduction

Prostate cancer has been the most common cancer affecting men in the USA, and the second leading cause responsible for cancer deaths [1]. Mortality can only be decreased by early diagnosis of organ confined cancer. Transrectal ultrasound guided (TRUSG) biopsies are usually indicated when the prostate specific antigen (PSA) level is elevated, and/or an abnormal digital rectal examination (DRE) finding exists. Low sensitivity and specificity of both PSA and DRE have led a low diagnostic yield of initial TRUSG biopsies, so that repeat biopsies are frequently required. Moreover, there has been no universally accepted biopsy protocol.

The operator dependent nature of DRE may lead to underestimation of its role in terms of specificity for cancer detection. Therefore, we conducted a clinical prospective study combining standard 12-core systematic TRUS guided biopsies and 2 additional cores under DRE guidance in case of suspicious DRE, to further elucidate significance of DRE properly performed by an experienced urologist.

Materials and Methods

A total of 119 consecutive patients who either have a PSA level greater than 4ng/ml and/or suspicious DRE findings underwent standard 12 core systematic TRUS guided biopsies and 2 additional cores obtained under the finger guidance in DRE + cases. Patients were divided into three groups according to their PSA level. Group I (n=8): PSA <4ng/ml, Group II: (n=62) PSA 4-10ng/ml, Group III (n=49): PSA>10ng/ml. The patients whose pathology results were benign and have had no abnormalities on prostate were excluded from the study. Then the cancer detection ratios of both modalities were obtained according to the DRE abnormal patients.

Results

The distribution of groups and DRE and biopsy findings are represented in Table 1. First group had a PSA level less than 4ng/ml, they would have been missed without DRE examination. In the first group there were 3 patients with abnormal DRE findings, and 2 of 3 were detected as cancer with TRUSG standard biopsies. The biopsies additionally taken with DRE did not avail to find cancer different from TRUSG biopsies.

One of the detected cancers was different from those which were taken by TRUSG biopsies (Table 2).

The group II had 1 cancer only detected by DRE guided biopsies (p:0,4) (Table 3).

Overall the biopsies additionally taken with DRE helped to be diagnosed 1 of the 27 cases. No major complications were seen. Hematuria and hemospermia were among the transient minor complications.

Discussion

TRUS guided biopsies are the only way for definitive diagnosis of prostate cancer. It is of utmost importance to detect the cancer in the initial biopsy if it exists. Thereby, the patients would have a better chance for cure, on the other hand will be saved from unnecessary repeated biopsies. Six quadrant biopsies had been accepted as the gold standard, however, it is associated with a relatively high false-negative rate of 15% to 31% [2, 3]. Extensive biopsies particularly from far lateral aspects of the gland yielded higher detection rates [4].

Although there is no universal agreement upon the biopsy protocol, any abnormality during DRE examination and/ or elevated PSA level are general indications for prostate biopsy. Currently, the majority of the prostate biopsies turn out to be negative either because of low specificity of PSA and DRE or low detection rate of biopsy itself. In order to avoid unnecessary biopsies, age, %fPSA, PSA density, PSA velocity, prostate health index (phi) were proposed [5]. On the other hand, various attempts have been made to increase the detection rate of TRUSG biopsies such as saturation biopsies more than 20 obtained through the perineum, in accordance with the prostate volume. However, the complication rate also increases as the number of cores, particularly in younger patients.

MRI guided biopsies, MRI and TRUS fusion techniques are not readily available and cost-effective currently in daily practice, so that we have to continue to use the same tools unless proved otherwise. Since both radiologists and urologists have been performing TRUS guided biopsies, a proper DRE may be underestimated oftentimes. DRE is not usually sensitive for the tumors less than one centimeter [6]. It has been shown that if the initial biopsies are negative in the patients with a PSA level greater than 20ng/ml, second biopsy has a substantial chance for the diagnosis of prostate cancer [7].

Prakash and colleagues compared 10 cores versus 16 cores in DRE + cases without targeted biopsies. Although they found a significantly increased detection rate with 16 core biopsies, additional DRE targeted biopsies would probably enhance the detection rate in this group similarly, without a remarkable increase in the core number [8].

In this study, we showed a small percentage, but highly aggressive cancers may appear without PSA elevation, but only an abnormality can be found during a DRE before the disease is disseminated. In the first group, 3 patients were diagnosed solely based on DRE findings and subsequent biopsies, which in turn, revealed poorly differentiated high grade prostate cancer. Likewise, in the second group of the study, 1 out of 7 cancers was found only in DRE guided biopsy specimens.

Overall, DRE and TRUS guided systematic biopsy combination significantly enhanced the detection rate. TRUS evaluation of the prostate is of limited value; however, hypoechoic lesions should also be targeted, considering the fact that one third of them would harbor malignant tissue. In the study, hypoechoic lesions were also targeted and the number included in the systematic biopsies. Since DRE examination requires experience and expertise, it was our main point of interest. One of the drawbacks of 2 D TRUS evaluation is trajectories of the samples may not be visualized, therefore accurate mapping of the prostate may not be possible. Three dimensional TRUS guided biopsies provide tracking of each sample location and precise mapping, hence lessens duplicated biopsies as may be seen with two dimensional TRUS imaging [9].

In the Group III, DRE guided biopsies did not do any better compared to systematic biopsies. This may be explained that the higher the PSA is, the more prostate is involved in the disease, which increases the chance of being detected. However, due to our limited number of the patients in this group, this does not necessarily mean DRE is not important if the PSA level is >10ng/ml. We will continue to add DRE guided biopsies regardless of the PSA level when necessary.

Multiparametric MRI has become a very widely used tool for the detection of prostate cancer in the last decade. The fusion biopsy techniques have promising results especially for individually targeting biopsies rather than using a standart biopsy scheme [10].

The main limitation of this study is the small sample size. The operator dependent nature of DRE makes it prone to be interobserver variability even among the urologists. We suggest a thorough evaluation by DRE of each and every patient to better keep our patients out of the harm’s way.