The comparison of single port and multiport robot radical prostatectomy in terms of efficacy and safety.

We read the recent published paper in Translational Andrology and Urology by Wei and colleagues entitled “Efficacy and safety of single port (SP) robotic radical prostatectomy and multiport (MP) robotic radical prostatectomy: a systematic review and meta-analysis” (1). They carried out a meta-analysis to make the comparison of single port and multiport robot radical prostatectomy in terms of efficacy and safety. We appreciate Wei et al. for the valuable study, however, after a careful learning of the literature, several limitations should be noticed.

First, in the results section of the abstract, the authors mentioned that the results of this meta-analysis were robust through sensitivity analysis. In figure 7, we found that the effect size of mean difference was statistical difference between the SP and MP groups (Z=2.37, P=0.02). However, after excluding the study by Moschovas et al. (2) in figure 8, the blood loss between the SP and MP groups was no statistical difference (Z=1.59, P=0.11). Therefore, we believed that Moschovas et al.’s study had a significant effect on the results of meta-analysis as the sample size of this study was larger that the sum of sample sizes of the remaining studies; hence, the results of this meta-analysis were easily influenced by this study (2).

Second, in the publication bias and sensitivity analysis results section of the study, Wei et al. demonstrated the heterogeneity of this study was mainly caused by the research by Moschovas et al. (2). However, there was no significant heterogeneity observed in figure 7 before excluding Moschovas et al.’s study (P=0.76, I2=0). Furthermore, there was also no significant heterogeneity showed in figure 8 after excluding Moschovas et al.’s study (P=0.78, I2=0). Therefore, we believe that Moschovas et al.’s study was not the source of the heterogeneity.

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