BPH is commonly observed in older adults [10], and prostate volume tends to increase with age [11]. Surgical intervention is necessary for patients with a large prostate volume or BPH-related complications such as bladder or recurrent urinary tract stones. Furthermore, medications for BPH often have a high discontinuation rate over time, with approximately half of the patients discontinuing treatment within 2 years [2]. Moreover, α1-blocker monotherapy or discontinuation of oral therapy is a risk factor for surgery [2]. In Japan, which currently has an aging population, there is an anticipated increase in the number of patients requiring surgical intervention for BPH.

However, older adults often present with various complications, including geriatric syndromes. Geriatric syndromes encompass several conditions, such as osteoporosis and dementia, which have a multi-organ effect. As a result, surgeries in older patients are often considered high risk owing to the presence of comorbidities and aging. Screening tools such as the Charlson Comorbidity Index and G8 have been developed to assess and identify high-risk cases. The Charlson Comorbidity Index assigns scores based on the presence of comorbidities, and higher total scores are generally associated with poorer prognoses [12]. G8 is a functional assessment tool used to evaluate activities of daily living and prognosis in the older population. A G8 score < 14 is generally indicative of a poor prognosis [13]. In this study, compared with the TUEB group, the PUL group had a lower mean G8 score of 14, indicating higher risk and poorer prognosis among older patients. Additionally, the PUL group included older patients with a higher Charlson Comorbidity Index score compared with the TUEB group.

In 2011, PUL was the first surgical procedure for which outcomes were reported on a global scale [5]. In the initial report, a group of 19 Australian patients showed favorable IPSS outcomes 1 year after undergoing PUL. Subsequently, the efficacy and safety of PUL were evaluated in a multicenter, prospective, randomized, controlled blinded trial [14]. A 5-year follow-up report in 2017 showed an improvement in IPSS within 2 weeks postoperatively, which was maintained for 5 years [15]. Consistent with previous reports, the current study observed improvements in IPSS but also used two symptom questionnaires developed in Japan, the OABSS [16] for OAB symptoms and the CLSS [17] for core or key symptoms in several conditions, for a more detailed study. The CLSS questionnaire focuses on 10 key symptoms selected from a list of 25 established by the International Continence Society Standardization Committee. In the present study, a notable finding was the improvement in storage domains, including nocturia, in the PUL group; however, it was also noted that more patients had selected nocturia as the most influential quality of life domain. This improvement was not captured by the IPSS questionnaire alone but was evident when using the CLSS and OABSS questionnaires. The IPSS, OABSS, and CLSS have distinct focuses, timeframes, and evaluation objectives. Specifically, although the IPSS assesses symptoms over the past month, both the OABSS and CLSS evaluate symptoms over the past week. This difference allows the OABSS and CLSS to more precisely reflect the patient’s condition 1 month postoperatively, whereas the IPSS might be influenced by the immediate effects of the surgery. The IPSS primarily evaluates symptom frequency, excluding nocturia, whereas the OABSS evaluates symptoms based on specific counts over 1 week, again excluding nocturia and daytime frequency. Additionally, the OABSS assesses incontinence, which is not part of the IPSS, thus allowing for the diagnosis and grading of overactive bladder [18]. However, the CLSS differs from both the OABSS and IPSS because it does not evaluate the patient’s condition based on specific counts or frequencies; instead, it gauges the level of discomfort that the patient feels by using answers such as “none,” “occasionally,” “sometimes,” and “always” [17, 19]. Furthermore, although the IPSS includes four questions related to voiding, the CLSS, which aims to provide a comprehensive assessment, includes only three questions. The CLSS omits questions about interrupted streams and includes two questions about pain. We evaluated the responses to the IPSS Q7, OABSS Q2, and CLSS Q2 by seven patients who reported nocturia as their most bothersome postoperative symptom, as determined by the CLSS. Notably, all seven patients experienced nocturia before surgery; however, their postoperative outcomes were disparate. Three patients exhibited improvement, one patient experienced worsened symptoms, and the remaining three patients experienced no change (Supplementary Table). These findings suggest that as other symptoms improve, nocturia may have more of an impact on the patient’s quality of life and could be considered the most influential quality of life domain.

Therefore, the incorporation of the CLSS and OABSS allows for a more comprehensive and straightforward assessment of these symptoms.

TURP has traditionally been considered a reference surgical method for treating BPH [20]. Prospective randomized controlled trials comparing PUL and TURP have been conducted [21]. Both groups demonstrated significant improvements in symptoms and MFR. Although TURP was superior to PUL, particularly in terms of improvement in IPSS and MFR, postoperative worsening of urinary incontinence was observed in the TURP group but not in the PUL group [22]. TUEB shows better efficacy than TURP for treating BPH with a large prostate volume. TUEB is superior to TURP in the complete endoscopic resection of prostatic adenomas but with a longer operative time and significantly higher postoperative incidence of urethral stricture and stress urinary incontinence [7]. Compared with outcomes previously reported at our institution for TUEB [7], TUEB was better than PUL in terms of IPSS and Qmax in younger and less complicated patients. However, urine volume was increased in PUL, and the postoperative PVR was similar in both the groups. No significant complications were observed in any patient. Furthermore, when patient backgrounds are standardized for key preoperative characteristics in PUL and TUEB, the therapeutic outcomes of both procedures are considered closely aligned. This finding suggests that PUL is minimally invasive and offers several benefits.

This study had some limitations. The limitations of our study include the lack of strict control of variables typical in prospective studies, which may result in information bias due to subtle differences in patient characteristics. Furthermore, our patient cohort, derived from a single institution, may not accurately represent a broader population, potentially affecting the external validity of our findings. Although the number of patients was small, Cohen’s d values were sufficiently large to provide sufficient power, and the questionnaire used and comparison with the TUEB have not been reported previously, making this the first study in Japan. In Japan, PUL is indicated only for elderly patients who are at high risk, and conducting a sexual function assessment of such patients can be challenging. Therefore, this study did not include sexual function evaluations. Another limitation of this study was the short follow-up period of only 1 month. This procedure was introduced in Japan in April 2023, and it is currently limited to high-risk cases, resulting in a low number of cases nationwide since its implementation. Therefore, longer follow-up periods were not possible. As a result, Japan-specific outcome data was not available. Although future studies involving longer durations and larger cohorts are needed, this study may provide evidence to support the adoption of this new treatment modality in Japan.

In conclusion, this study reports the short-term results of PUL and safely demonstrates its efficacy in high-risk older patients. It is anticipated that the introduction of minimally invasive surgery in Japan will lead to an increase in the number of BPH surgeries, which are currently declining.