Grid‐based cognitive diagnostic prostatic biopsy without transrectal ultrasonography

Prostate and colorectal cancers are the second and third most common malignancies affecting men globally [1]. Abdominoperineal resection is the standard of care surgical treatment for patients with malignancy of the distal rectum or anal canal, while pan-proctocolectomy may be indicated for patients with inflammatory bowel disease and familial adenomatous polyposis [2]. Both these procedures require the removal of the rectum and anal sphincteric complex, with the formation of a permanent end colostomy, which negates the possibility for (transrectal ultrasound) TRUS imaging to guide diagnostic prostate biopsy. The current literature (mostly based on small patient cohorts) describes prostatic biopsies performed via the transperineal or transgluteal approach under radiological guidance with the use of transperineal (or less commonly transurethral or transabdominal) ultrasonography, MRI, or CT imaging (Table 1). Regardless of the imaging technique, all reported approaches require significant investment in resources (theatre and imaging equipment) as well as technical knowhow (urological and imaging). Among the reported series, only two have presented more than 10 patients for whom transperineal ultrasonography was employed to guide prostatic biopsies (Table 1). There remains no consensus on the optimal approach for securing histological diagnosis of prostate cancer when TRUS is not possible, especially when transperineal ultrasonography is not readily available [3]. Here, we describe our technique for grid-based cognitive diagnostic prostatic biopsy without TRUS. In the period June 2017 to September 2022, 15 patients with a history of either abdominoperineal resection or pan-proctocolectomy (n = 11 and n = 4, respectively) underwent investigation for prostatic lesions revealed by MR prostate imaging (with ≥score 3 out of 5 in accordance with the Prostate Imaging–Reporting and Data System v2) at the Department of Urology, NHS Greater Glasgow and Clyde, Glasgow, UK. Each of the scans was reviewed by a multidisciplinary team to confirm the location of the suspicious lesions [4]. All biopsies were performed by a single experienced urological surgeon (H.Y.L.). Five of the patients underwent the procedure under local anaesthesia, while 10 patients received general anaesthesia. The small number of cases performed under local anaesthesia were attributable to strong patient preference and the need to avoid a general anaesthetic during the period of the COVID pandemic. Two patients (out of 15) underwent a repeat procedure as the samples obtained in the first attempt were inconclusive. For these two patients, a relatively small number of biopsy cores was obtained (4 and 5 cores, respectively) in the first attempt. The number of cores was increased in the second attempt, with 16 and 22 tissue cores obtained, respectively. Overall, the median number of cores obtained was 11 (range 4–25). In future, with more experience in determining the location of the prostate gland based on surface anatomy and estimates from MRI, we propose that a more limited biopsy schedule could be considered. Fourteen of 15 patients were confirmed to have prostate cancer (Table 2), giving an overall cancer detection rate of 93%. All patients were discharged on the same day, and no patient experienced post-procedure sepsis or urinary retention. Our cancer detection rate exceeds those previously reported, which ranges from 50% to 83% (Table 2). Six patients had their cancers detected at early stage (T2) and could be considered for radical treatment. While the mean prostate volume was just under 38 cc (or mL) (Table 2), three patients had prostate volume ≥50 cc (or mL), further suggesting the clinical usefulness of this approach in enlarged prostates. The range of serum PSA levels (4.3–40 ng/mL) was relatively wide, with nine patients presenting with PSA levels <15 ng/mL. Apart from one case, all detected prostate tumours were clinically significant, with a Gleason score ≥7, including four patients diagnosed with highly aggressive disease (≥Gleason score 8/Gleason Grade Group 4; Table 1). More than 3500 patients undergo rectal surgical procedures in the UK each year, with >1000 of these patients requiring abdominoperineal resection [5, 6]. The male patients among them are also reported to be at increased lifetime risk of prostate cancer [7, 8]. As a result of the inability to perform conventional TRUS, many of these patients are not investigated in a timely manner to achieve early detection of clinically significant prostate cancer. There are currently no specific guidelines for detecting prostate cancer in patients without a rectum, resulting in substantial delay in investigation and diagnosis [3]. We believe our simple yet effective approach to performing prostatic biopsies without the use of TRUS will help avoid unnecessary delay in the prostate cancer diagnostic pathway for this patient group. It is also worth noting that in the post-proctectomy setting, increased periprostatic scarring and fibrosis may impair confidence in assessing the depth of the prostate from perineal skin. The impact of this report, however, is limited by the fact that all procedures were performed by one urologist. At present, highly experienced surgeons are probably required to determine when the biopsy needle is in contact with the prostate gland. In the future, we hope to explore methodology to measure the distance from perineal skin to the prostate gland based on the MR prostate images to guide the biopsy procedure. It is therefore necessary to test whether the reported technique can be easily adopted in other centres/by other urologists worldwide. The authors thank urology colleagues across the West of Scotland for patient referrals, Jackie Young and her theatre team for their support, staff from Medical Illustration for the illustrative photographs, and importantly patients for their willingness to consent to our biopsy approach.. D.S.S. received registration fee support from Ferring Pharmaceuticals Ltd. to attend European Association of Urology 2024. J.M. and H.Y.L. have no disclosures. Appendix S1. References. 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