Low-intensity extracorporeal shockwave therapy for chronic prostatitis/chronic pelvic pain syndrome: a retrospective single-center observational study in Japan

Introduction

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a chronic and heterogeneous clinical syndrome characterized by pelvic pain, lower urinary tract symptoms, sexual dysfunction, and impaired quality-of-life (QoL). Despite the availability of various pharmacological and non-pharmacological treatment options, many patients continue to experience persistent symptoms, making CP/CPPS a challenging condition to manage.

Low-intensity extracorporeal shock wave therapy (Li-ESWT) has emerged as a promising non-invasive treatment option for CP/CPPS. The first randomized, double-blind, placebo-controlled trial demonstrated significant symptomatic improvement following Li-ESWT (1). Since then, multiple systematic reviews and meta-analyses have consistently supported its efficacy and safety, particularly with respect to pain relief and improvement in QoL (2-4).

More recently, several prospective clinical studies from Asian countries or regions, including Taiwan (China), the mainland of China, and South Korea, have also reported favorable outcomes following Li-ESWT, even in patients with persistent symptoms despite conventional medical therapy (5-7). These findings suggest that Li-ESWT may represent a promising treatment option for selected patients with treatment-refractory CP/CPPS. Proposed mechanisms include anti-inflammatory effects, neuromodulation, improvement of local microcirculation, and reduction of pelvic floor muscle hypertonicity, although the precise mechanism of action remains incompletely understood.

Despite the growing body of evidence, most published studies have been conducted under controlled clinical research settings, whereas real-world evidence remains relatively limited. Furthermore, although clinical evidence has accumulated from Europe and several Asian countries, published data from Japanese patients remain scarce. Because patient characteristics, treatment patterns, and healthcare systems may differ among countries, real-world data from Japanese clinical practice may complement existing evidence and improve its generalizability.

Therefore, the present study aimed to evaluate the effectiveness and safety of a standardized four-session Li-ESWT protocol in patients with CP/CPPS treated in routine clinical practice at a Japanese outpatient urology clinic. By providing real-world clinical data from a treatment-refractory Japanese cohort, this study was designed to complement the existing evidence regarding the real-world clinical use of Li-ESWT for CP/CPPS. We present this article in accordance with the STROBE reporting checklist (available at https://tau.amegroups.com/article/view/10.21037/tau-2026-0381/rc).

Methods

Study design and patients

This was a retrospective, single-center observational study conducted at Osaka Umeda Shinshi Clinic, a specialized outpatient urology clinic in Osaka, Japan. The study included 19 consecutive patients with CP/CPPS who underwent Li-ESWT between July 2023 and June 2025.

Eligible patients had previously been diagnosed with chronic prostatitis at other medical institutions and continued to have persistent symptoms despite at least six months of conservative treatment, including various pharmacological therapies. At Osaka Umeda Shinshi Clinic, all patients underwent urinalysis and urine culture to exclude urinary tract infection. Patients without evidence of infection were diagnosed with CP/CPPS by a board-certified urologist based on clinical symptoms and the absence of identifiable infection or other urological conditions. Patients with abnormal urinalysis, positive urine culture, or other urological diseases that could explain pelvic pain were excluded.

Because this was a retrospective observational study reflecting routine clinical practice, no formal sample size calculation was performed.

Intervention

Li-ESWT was performed using the DUOLITH^® SD1 T-TOP ultra system (STORZ MEDICAL AG, Tägerwilen, Switzerland). All treatment sessions were performed by a board-certified urologist experienced in Li-ESWT using a standardized treatment protocol.

Shock waves were delivered transperineally to the perineal region overlying the prostate. No individualized targeting of specific pelvic floor muscles or trigger points was performed. Treatment parameters consisted of an energy flux density of 0.25–0.35 mJ/mm², a frequency of 8.0 Hz, and 3,000 pulses per session. Treatments were administered once weekly for four consecutive weeks. No anesthesia or analgesics were used, and concomitant medications, if any, were not modified during the treatment period.

Outcome measures

The primary outcome was the change in the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) total score. Secondary outcomes included changes in the pain, urinary, and QoL domain scores. Assessments were performed at baseline and immediately after completion of the four treatment sessions.

Statistical analysis

Continuous variables are presented as mean ± standard deviation (SD). Differences between baseline and post-treatment values were analyzed using paired t-tests or Wilcoxon signed-rank tests, as appropriate, according to the data distribution. A two-sided P<0.05 was considered statistically significant.

Ethics statement

This retrospective observational study was conducted at Osaka Umeda Shinshi Clinic, where the patients were treated and clinical data were collected. Because the clinic did not have an institutional ethics committee available for reviewing this study, approval was obtained from the Safety Assessment Committee for Clinical Research in Japan (SACRJ), an independent external ethics committee (approval No. 202603-12-01P). The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The requirement for written informed consent was waived because the study used anonymized clinical data. Information regarding the study was made publicly available on the institutional website, and all eligible patients were given the opportunity to opt out.

Results

A total of 19 patients were included in the study, and all completed the four-session Li-ESWT protocol. Baseline patient characteristics are summarized in Table 1, and changes in NIH-CPSI total and domain scores are presented in Table 2.

The mean NIH-CPSI total score significantly decreased from 25.9±5.4 at baseline to 21.6±7.5 after treatment (mean change, −4.32±4.27; median change, −4; P<0.001).

As shown in Figure 1, treatment responses varied substantially among individual patients. Six patients (31.6%) achieved clinically meaningful improvement (≥6-point reduction), 10 (52.6%) experienced modest improvement (1–5-point reduction), and 3 (15.8%) showed no improvement or worsening. Overall symptom improvement was observed in 16 patients (84.2%).

Figure 1 Distribution of individual changes in NIH-CPSI total score after Li-ESWT. A reduction of ≥6 points was considered clinically meaningful improvement. CI, confidence interval; Li-ESWT, low-intensity extracorporeal shock wave therapy; NIH-CPSI, National Institutes of Health Chronic Prostatitis Symptom Index.

As summarized in Table 2, significant improvements were observed in the pain domain (11.5±3.2 to 9.2±3.5, P<0.01) and the QoL domain (10.1±1.4 to 8.5±2.7, P<0.01), whereas no significant improvement was observed in the urinary domain (4.3±3.2 to 3.9±3.6, P=0.31).

No serious adverse events were observed throughout the study period.

Discussion

In this retrospective observational study, a standardized four-session Li-ESWT protocol was associated with a significant reduction in overall symptom burden among patients with CP/CPPS who had persistent symptoms despite previous conservative treatment. Significant improvements were observed in the pain and QoL domains, whereas no significant improvement was observed in urinary symptoms.

Our findings are generally consistent with the existing evidence supporting Li-ESWT for CP/CPPS. Since the first randomized, placebo-controlled trial by Zimmermann et al. (1), several systematic reviews and meta-analyses have consistently demonstrated the efficacy and safety of Li-ESWT, particularly with respect to pain relief and improvement in QoL (2-4). In addition, prospective studies from Taiwan (China), the mainland of China, and South Korea have reported favorable clinical outcomes, including in patients with persistent symptoms despite conventional medical therapy (5-7). Although direct comparisons should be interpreted cautiously because of differences in study design, patient populations, treatment protocols, and outcome measures, our findings are broadly consistent with these previous reports.

Several biological mechanisms have been proposed to explain the therapeutic effects of Li-ESWT, including anti-inflammatory effects, neuromodulation, improvement of local microcirculation, and reduction of pelvic floor muscle hypertonicity. However, the present study was not designed to investigate these mechanisms, and therefore no conclusions regarding the mechanism of action can be drawn.

Treatment responses varied considerably among patients. Overall symptom improvement was observed in 84.2% of patients, whereas clinically meaningful improvement, defined as a reduction of at least six points in the NIH-CPSI total score, was achieved in 31.6%. As illustrated in Figure 1, treatment responses ranged from marked improvement to slight worsening. Although study eligibility required persistent symptoms for at least six months, many patients had experienced symptoms for several years before referral to Osaka Umeda Shinshi Clinic, reflecting a treatment-refractory population commonly encountered in routine clinical practice. In this clinical setting, even modest symptom improvement may represent a meaningful therapeutic benefit. Because of the limited sample size, responder analyses to identify predictors of treatment response were not feasible. Larger prospective studies are needed to determine which patients are most likely to benefit from Li-ESWT.

No serious adverse events were observed, supporting the safety and feasibility of Li-ESWT as an outpatient treatment.

Several limitations should be considered when interpreting these findings. First, this was a retrospective, single-center observational study involving a relatively small number of patients. Second, the absence of a sham-control or comparator group precludes definitive conclusions regarding treatment efficacy, and placebo effects cannot be excluded. Third, outcomes were assessed only immediately after completion of treatment; therefore, the durability of treatment response remains unknown. Previous studies have suggested that symptomatic improvement may persist for several months after Li-ESWT (8); however, long-term outcomes were beyond the scope of the present study. Finally, because of the limited sample size, subgroup analyses to identify predictors of treatment response could not be performed.

Despite these limitations, this study provides real-world clinical data regarding the use of Li-ESWT for CP/CPPS in a Japanese outpatient urology setting. Although clinical evidence has accumulated from Europe and several Asian countries, published data from Japanese patients remain scarce. The present findings therefore complement the existing literature by providing practical information regarding the feasibility, safety, and clinical outcomes of Li-ESWT in routine Japanese clinical practice. Further prospective multicenter studies with larger cohorts, appropriate control groups, and longer follow-up are warranted to better define the role of Li-ESWT in the management of CP/CPPS and to establish robust real-world evidence from Japan.

Conclusions

In this retrospective single-center study of patients with CP/CPPS and persistent symptoms despite conservative treatment, a standardized four-session Li-ESWT protocol was associated with significant improvement in overall NIH-CPSI scores, particularly in the pain and QoL domains, without serious adverse events. However, given the small sample size, absence of a control group, and short follow-up, larger prospective controlled studies with longer follow-up are needed to confirm these findings and better define the role of Li-ESWT in routine clinical practice.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://tau.amegroups.com/article/view/10.21037/tau-2026-0381/rc

Data Sharing Statement: Available at https://tau.amegroups.com/article/view/10.21037/tau-2026-0381/dss

Peer Review File: Available at https://tau.amegroups.com/article/view/10.21037/tau-2026-0381/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tau.amegroups.com/article/view/10.21037/tau-2026-0381/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Safety Assessment Committee for Clinical Research in Japan (SACRJ), an independent external ethics committee separate from Osaka Umeda Shinshi Clinic (approval No. 202603-12-01P). The requirement for written informed consent was waived because this retrospective observational study used anonymized clinical data.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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