Prostate biopsy is integral to prostate cancer diagnosis and treatment. Per the AUA and NCCN guidelines, management is based on PSA, patient status, and data from biopsy. Many men that seek urology care will require a prostate biopsy during their lifetime and associated complications are not negligible. This include but are not limited to fever, infection, sepsis, urinary retention, and rectal bleeding, and includes up to 4–5% hospital admissions (6, 7, 15).
There has been a recognized increase in the prevalence of antibiotic resistant organisms, resistance in rectal flora with ESBL bacteria and quinolone-resistant bacteria and transrectal prostate biopsy sepsis. (7, 14, 15, 16) Consequently, targeted antibiotics to prebiopsy rectal swabs, or additional antibiotics on top of the AUA recommended ones have been used. However, this often cause more resistant bacteria to arise (7, 14, 15, 16). This was seen in our institution; E.Coli resistance to Levofloxacin was found to be 15% and to Bactrim was 26%. Our antibiotic stewardship team recommended that we switch to Fosfomycin. However, we noted this costed $2104/daily dosing. This is compared to Bactrim and Levaquin at $10/daily dosing. After contemplation we then made the decision to start using in-office transperineal biopsies without antibiotics and compared them to transperineal biopsies with a focus on the infectious risks between them. The rationale for removing the antibiotic prophylaxis is that the TPB needle does not cross the rectum. Instead, the needle goes through 1 prepared skin entry and urinary tract was screened for infection immediately prior to the procedure.
It is important to note that nearly all studies, including comparative and meta-analyses papers, originate internationally where many studies are based on biopsies performed with MRI fusion targeted biopsies and saturation biopsies in the operating room with most cases using general anesthesia. Although performed transperineally, these used a brachytherapy template or freehand, and therefore likely differed in length of time and in methodology.
INFECTION AND RETENTION
Our data comparing TPB without antibiotic prophylaxis and TRB showed a lower complication rate and lower post-biopsy infection rate with TPB. Moreover, we did not have any post-biopsy admissions for sepsis in TPB. We had multiple admissions with our transrectal biopsy cohort, including a multi-day ICU admission for IV antibiotics due to urosepsis.
Similar outcomes have also been reported. A meta-analysis performed by Xiang et al found in studies comparing transperineal and transrectal biopsies (some including MRI fusion-targeted and saturation biopsies) that the transperineal approach decreased the risk of rectal bleeding and fever (8). Grummet et al published in 245 transperineal biopsies (all performed under general anesthesia with a brachytherapy grid) that they had no readmissions for infection (7). Pepe et al noted in their cohort of patients who underwent freehand transperineal biopsy, the post-procedure UTI rate was 0.7%. None had sepsis. However, in this study Pepe et al did administer antibiotic prophylaxis, and many of their biopsies were saturation biopsies which were found to have more a higher rate of complications than standard 12 core biopsies (24). In a single center retrospective study using in-office transperineal biopsy, Meyer et al saw no post-biopsy infections in their 43 patient non-comparative study (9).
On the other hand, with transrectal biopsies, the published post-biopsy infection rate is as high as 7%, with sepsis rates up to 3.6% (7, 16).
These findings should not be surprising, as during transrectal biopsies the biopsy needle passes from rectal mucosa into the prostate which in principle violates a potentially sterile area. This results in rectal flora being introduced into the prostate, which as we know is a very vascular gland and in effect increases a significant risk of bloodstream invasion of the rectal flora (7). However, with transperineal biopsy Thompson et al reports there are lower rates of plasma endotoxin and bacteremia with only skin flora found with bacteremia, theoretically giving then a lower risk of infection/sepsis (17).
With urinary retention as a known complication of prostate biopsy, we evaluated post-biopsy retention rates as well. Our study also showed transperineal biopsy had a lower rate of urinary retention post-biopsy than transrectal biopsy, at 0.9% and 3.6%, respectively. In comparison, Meyer et al found a retention rate of 4.7% in their 43 patient transperineal biopsy experience (9). In addition, Huang et al reported a 3% rate of retention with TPB compared to a 12% rate after TRB, with risk factors being large prostate volume, bulging prostate transitional zone and high IPSS scores (25). Moreover, in both meta-analyses by Xiang et al and Shen et al, the retention rate after TPB was found to be to be similar to TRB – and this was including MRI fusion-targeted biopsies and saturation biopsies that were not performed in-office (8, 18).
Another discussion point is the efficacy of transperineal compared to transrectal biopsy in detection of prostate cancer. There have been numerous studies internationally, one of the larger ones including a study by Hara et al, as well as the meta-analyses by Xiang et al and Shen et al eliciting that the two modalities were similar in cancer detection and diagnostic efficiency (8, 18, 20).
It has also been reported that the transperineal approach was better at detecting tumors in the apex and transitional prostate zones (12, 13), though this is refuted in other studies that note there is no difference in peripheral, transitional, or apex detections between the two approaches (18). Historically, it is difficult to access the anterior zone of the prostate in particular; in this location, tumors are found at higher grades and stages, and improved ability has been noted to access this area with the perineal approach (9, 27).
In our study, detection of prostate cancer by TPB is similarly efficacious as compared to that reported by multiple studies including those by Meyer et al, Hara et al. and Xiang et al. (8, 11, 20). Due to the planes of the TRB and similarities with cognitive fusion MRI, we found anecdotally that using cognitive fusion MRI for targeted biopsy was much easier to target accurately than standard TRB due to the field of view we are able to appreciate with TPB.
Xiang et al found in their meta-analysis that patient pain was found to be increased with the transperineal approach; though many studies included in the meta-analysis had patients undergoing longer procedures with MRI fusion targeted and saturation biopsies (8). However, Bass et al. noted in their study that approximately 90% of men were “not dissatisfied” after in-office transperineal biopsy and would recommend it (21). Furthermore, Merrick et al and Smith et al assessed pain with “visual analog scales”, taking scores from 0 to 10 for men undergoing transperineal biopsy, with 10 being “the worst pain imaginable”. Merrick et al and Smith et al found the worst scores were with associated with the local anesthetic injection, recorded at (4.2 ± 1.8), and (3.29 ± 1.64), respectively, with the rest of the procedures scores being significantly less than this and thus concluding that the patient satisfaction was appropriate. (22, 23). In our series, very few patients were unable to undergo the procedure; however, we did not measure patient satisfaction.
The cost of a TPB and TRB are similar regarding in-office necessities and instruments; the PrecisionPoint™ device for TPB costs $178, compared to the biplane guide for TRB at $22.25. Otherwise, both require similar local anesthesia, transrectal US, and a biopsy. However, by reducing infection rates our healthcare costs are reduced substantially. Evan et al performed a cost analysis of post-biopsy infection admissions in a database of insurance claims between 2005–2012 and found the mean total payment for duration of each patient hospitalization for infection was $14,498.96 (11). In addition, they reported that post-biopsy infection complications were found to cost $115 million in the 8-year time period analyzed, averaging to $14,000,000/year; when this was extrapolated to the entire male Medicare population, the estimation was at 623 million dollars annually (11). In an attempt to remedy this, Taylor et al used a rectal swab culture-directed antibiotic prophylaxis approach for their biopsies which resulted in a cost reduction of $4500 per avoided infection alone (26).
In our study, using transperineal biopsies could elicit significant decrease in infection along with decrease in antimicrobial resistance due to reduced needs for antibiotic prophylaxis, lowered infection rates, and hospital admissions for post procedure infection. After appreciating the numbers presented above, with each avoided infection and hospitalization, the cost reduction in healthcare resources related to transperineal biopsy could be drastic.
Limitation of our study included the retrospective nature and lack of randomization. Additionally, our study does currently have a small sample size and is at a single institution. However, our results do have promising data towards the applicability of transperineal biopsy without antibiotic prophylaxis in mainstream prostate cancer management.