Hypothesis / aims of study
The transurethral resection of the prostate (TURP) is one of the gold standard surgical treatments for benign prostatic obstruction (BPO), but it is unknown how much tissue must be resected on surgery in order to achieve good results. Objective: to assess whether the amount of the prostate tissue resected influences on short and medium term follow up.
Study design, materials and methods
It was developed a prospective study in a single center between May 2020 and August 2022, embracing subjects with severe Lower urinary tract symptoms (LUTS) due to BPO, refractory to conservative treatment. Subjects with different prostate sizes (< 80cc³) were analyzed, including clinical parameters (IPSS questionnaires, comorbidities), urodynamic parameters meeting obstruction criteria (Bladder Outlet Obstruction Index - BOOI > 40), and good detrusor function (Bladder contractility index>100) were included in the analysis. Patients with urethral stenosis, neurological conditions or prostate cancer were excluded. TURP was performed in all of them. After the procedure, patients were assessed at 1, 6 and 12 months follow up.
The primary endpoint was to compare whether the amount of resected tissue after TURP influences uroflowmetry at 12 months follow up (Qmax, ml/second). The secondary endpoint was to compare different percentages of resected tissue (RPT – resected prostate tissue = resected prostate tissue/prostate volume*100) and its relation to the outcomes, according to groups:
• Group 1 – RPT > 60 %
• Group 2 – RPT 30 – 60%
• Group 3 – RPT < 30 %.
Statistical analysis
The statistical analysis was performed with software JAMOVI version 1.6 (Computer Software). It was used the Pearson or Spearman test to numeric variables, according to the distribution data. After the groups were splitted, according to the percentage of RPT, pre-operative and post-operative data were assessed through ANOVA or Kruskall-Wallis test. The homogeneity was analyzed by the Levene’s test and the distribution of the data was assessed by the Shapiro-wilk test.
This study was performed according to Declaration of Helsinque and approved byy the ethics committee of Paulista School of Medicine – Federal University of São Paulo (CAAE: 37969020.6.0000.5505).
Results
Ninety-six patients were studied, with mean age of 70,4 ± 7.96 years (mean ± Standard deviation). At baseline, prostate volume was 78.5 ± 51.8 cc³, Qmax was 6.03 ± 3.09 ml/sec and post void residual (PVR) was 113 ± 132 ml. Subjects had bothering symptoms, according to IPSS 24.9 ± 6.75. All of them were urodinamically obstructed (BOOI 86.7 ± 35.6) and good detrusor function (BCI 130 ± 28.6). Prostatic specific antigen (PSA) was 5.07 ± 5.04 ng/ml. The general RPT was 45.5 ± 27.7%.
The higher the RTP, the lower the PSA at 1 month follow up (p<0.001, R=0.521), as shown in figure 1. Nevertheless, it was not found correlation between the RTP and Qmax, IPSS or PVR, as shown in table 1.
In sub analysis, three groups had a great improvement in Qmax compared with baseline, nevertheless with no difference between them (Kruskal-wallis, p=0209). It was seen similar results when analyzed IPSS and PVR.
Figure 2 reveals Qmax variation in groups according to follow up.
There were no differences at 12 months follow up in IPSS, PVR (p respectively 0.388, 0.398).
Interpretation of results
There are a paucity of studies comparing the amount of prostatic tissue in a TURP and achieved outcomes, with controversial results. It is important to highlight that the previous study of the function of detrusor is essential.
Our study compared the amount of resected prostate tissue and its relation with subjective (measure by IPSS) and objective outcomes (measured by Qmax, PVR and PSA) in patients with bladder outlet obstruction and good detrusor function. At 12 months, we did not find association between the RTP and better outcomes, both objective or subjective.
These results contradict the premise that the main goal of TURP is maximum resection. We understand that a serious discussion is necessary with the patient, embracing features as his life expectancy and potential harms with a more aggressive surgery. The TURP aggressiveness can be verified assessing the hemoglobin drop (∆Hb), with statistical significance (the higher the RPT, the higher the Hb variation). Considering that BPO is a disease of the elderly, a more conservative surgery can fit better, mitigating possible complications in the procedure.
Hakenberg and col (1) showed that the quantity of resected tissue apparently interferes in outcomes. Nevertheless, Park and col (2) observed different results, therefore this remains a controversial issue.
We understand that the life expectancy and other characteristics must be considered in the treatment of BPO, as it is in prostate cancer, for example, with such watchful waiting protocols. TURP eventually can be more conservative and faster, mainly in patients with severe comorbidities, or in cases which sub-optimal results are tolerated, since short term outcomes are similar to those of patients undergoing maximal resection. These data can not be extrapolated to underactive detrusor function.
Concluding message
TURP improves clinical and urodynamic parameters at 1 year follow up, independent of the amount of resected prostate tissue, in patients with bladder outlet obstruction and good detrusor function, since the surgery is effective, verified by satisfactory PSA drop. Life expectancy and comorbidities must be considered to perform a safe TURP, mitigating complications and adverse events.