Hypothesis / aims of study
Testosterone plays a critical role in male reproductive function and several physiological mechanisms. Some studies suggest that disruption of the circadian rhythm can directly lead to decreased testosterone levels. Nocturia, a symptom that often causes sleep deprivation, can disrupt the circadian rhythm and cause lower testosterone levels in patients diagnosed with benign prostatic hyperplasia (BPH). Surgeries for BPH, such as transurethral resection of the prostate (TURP) or anatomical endoscopic enucleation of prostate (AEEP) [1], can effectively improve nocturia and lower urinary tract symptoms (LUTS), which may subsequently ameliorate testosterone deficiency (TD). In our previous publication, we reported that hypotestosteronemic patients experience an immediate elevation in their testosterone levels after the first month of AEEP [2]. In this study, we aim to conduct a longer follow-up to track the changes in the testosterone levels of these patients.
Study design, materials and methods
This is a retrospective study that includes the patients who underwent anatomical endoscopic enucleation of prostate (AEEP) from January 2018 to December 2021 at our hospital . We record the data of baseline demographics, preoperative and postoperative nocturia at 1.5 months after the operation. We also collected and compared the pre-operative testosterone level, post-operative testosterone level and the testosterone level at least 3 months after the surgery. Wilcoxon test and chi-square test were the main statistical methods.
Results
A total of 560 patients were included in this study. After excluding unmatched data, 303 patients were enrolled for the testosterone level analysis. We divided them into two groups based on the EAU guidelines with a cut-off at 3.5ng/mL: the low-testosterone group (<3.5ng/mL) and the normal-testosterone group (>=3.5ng/mL). The results showed a significant increase in testosterone levels for the whole patient population, as well as the low-testosterone group post-operation, and during the long-term follow-up for the normal-testosterone group (Table 1). Additionally, for the nocturia study, we divided the patients into the low-testosterone group and normal-testosterone group, and found significant improvement in nocturia for both groups and the whole patient population.
Interpretation of results
In our study, we found that testosterone levels improved in the low testosterone group 1.5 months after surgery, and in the long run, all patients benefited from increased testosterone levels 3 months after the operation. We believe that this improvement was due to a reduction in nocturia and a restoration of the circadian rhythm.
Although BPH treatments with alpha-blockers or transurethral resection of the prostate (TURP) may lead to similar increases in testosterone, previous reports have shown no correlation between BPH treatment and testosterone levels. This could be because medical treatments are generally less effective than surgical treatments like TURP, and because nocturia is the most troublesome symptom of BPH, medical treatment may fail to correct circadian rhythm adequately. Additionally, most studies of surgical treatments with TURP have focused on erectile function, and there are no previous publications discussing testosterone after prostate enucleation.
We believe that enucleation provides the best functional outcome in simple prostatectomy, particularly in the case of nocturia, which may explain why we observed an elevation in testosterone levels post-surgery. According to the EAU guideline, the evaluation of medical or surgical treatment outcomes is based on patients' subjective satisfaction. However, serum testosterone levels could serve as an objective evaluation target for BPH treatment.