Traditionally, the mainstay protocol of the biopsy method for PCa screening was done via 12-core TRUS biopsy. Several studies have shown the significance and suitable application of mpMRI in aiding PCa detection and diagnosis18,19. Therefore, many more studies have illustrated the advantages of MRI-targeted biopsy20–22, leading to its place as one of the default screening methods for PCa. Despite remarkable advancements in PCa diagnostic tools and modalities, studies have shown a fraction of patients with PCa that were not diagnosed and/or did not receive proper treatment based on the staging of PCa at diagnosis4,5. Studies regarding TTMB have demonstrated its effectiveness in detecting significant PCa, and many studies from our institution have illustrated TTMB’s effectiveness compared to that of other biopsy methods15–17. Thus, we aimed to demonstrate the role of TTMB and its efficacy during the clinical course of patients under AS and non-cancer.
A study by Song et al. has shown a long-term follow-up data of AS patients for 15 years, in which 38% of patients underwent radical treatment23, while Ha et al. reported 48.6% of AS patients that received radical treatment over a follow-up of four years24. Patients in both of the aforementioned studies underwent TRUS-bx and were subsequently treated by AS based on pathology obtained from the TRUS-bx cores. Compared to these studies, our study showed that 17.4% of patients underwent radical treatment over a mean follow-up period of 33.8 months. Our study design incorporated more strict criteria in determining AS eligibility by performing confirmatory TTMB after initial TRUS-bx or target bx via TRUS, thus an additional layer of the screening process and therefore resulting in a markedly low percentage of patients converting to radical treatment. Patients who received confirmatory TTMB have not presented inferior results, regarding the amount of patients converting to radical treatment, compared to those who received only TRUS-bx.
As for whether repeat biopsies reveal PCa that was previously undiagnosed in initial biopsies, Ploussard et al. have shown that initially, non-cancerous group patients with repeat biopsies during a mean time follow-up of 19 months have revealed 16.7% of newly diagnosed patients with cancer, with similar results for repeated biopsies25. Our study shows that a total of five patients (2.5%) have converted to radical treatment over a mean follow-up period of 31 months, with one repeat biopsy done. Further studies by Patel et al. have shown that patients with previous negative biopsies along with utilization of mpMRI have yielded 5.3% detection of csPCa in a 5-year follow-up span26. Our findings, along with aforementioned studies, show the benefits of TTMB and mpMRI, are such that by implementing and adhering to stricter criteria, patients are screened with higher accuracy, leading to scheduling patients for a much less intense follow-up course, with less clinical visits and invasive tests performed than otherwise indicated or traditionally done.
TTMB has many advantages over systematic TRUS-bx for confirming the eligibility of AS for PCa patients and holding a firm rationale for undergoing confirmatory biopsy in patients suspected of PCa. TTMB’s higher number of biopsy cores collected allows for a broader area of the prostate that could be examined, which can detect cancer in regions that would have been otherwise missed by a systematic 12-core biopsy. Additionally, the risk of post-biopsy urinary tract infection and urosepsis is significantly lower, which can lessen the medical cost and health burden for the patients. Additionally, performing a more extensive biopsy method as TTMB allows for a more comprehensive and accurate diagnosis of the patient’s current status, which allows for a more lenient follow-up term to monitor the patient’s condition. These advantages can minimize the rate of conversion to radical treatment in AS patients and csPCa detection in previously benign, non-cancerous patients.
However, TTMB is often performed under general anesthesia, and care must be taken to maintain sterility and the accuracy of such invasive tests. Although the risk of post-biopsy complications and infection is lower in TTMB compared to that of the transrectal approach, there exists the possibility of post-biopsy AUR, especially in patients with larger prostate volume11,12,15, underscoring the need for careful selection of biopsy modality for patients regarding prostate volume. Additionally, an extended follow-up duration can be considered for patients who underwent confirmatory TTMB, as opposed to patients that received traditional TRUS-bx. Although our report does not specifically demonstrate the clinical course of increasing follow-up duration, incorporation of such measures into the clinical protocol, based on the rate of conversion to radical treatment from AS and detection of csPCa from non- cancerous patients, does not seem farfetched. Moreover, extending follow-up duration can be favorable for the patients, as this would lead to less invasive tests performed on patients, improving the patients overall quality of life and sparing additional medical costs. Recent studies have highlighted the feasibility of performing TTMB under a local anesthetic setting, with results that are comparable to TTMB done under a traditional, general anesthetic setting27, which aids in maintaining the same level of excellent accuracy while lessening the burden on the patients.
Our study had some limitations. First, the retrospective nature of this study means that selection bias may have occurred that could affect our results. Second, a relatively short follow- up period could have limited the overall scope of our study, as a longer follow-up period could have yielded different results. Additionally, our study was done at a tertiary teaching hospital in the most populous city in South Korea which can cause the issue generalizability to the general population of South Korea. Furthermore, all AS patients were seen by several different oncologists and therefore did not follow the same follow-up strategies regarding biopsy modalities and/or tests done, and many factors, such as patient and doctor preferences, may have partcipated in determining the clinical course regarding biopsy protocol (TRUS vs TTMB). In contrast, our study suggests the effectiveness of TTMB and its useful role in PCa screening as one of the screening and biopsy modalities.