| Objectives:This study aims to investigate the epidemiological and pathological characteristics(malignancy,volume,spatial distribution,etc.)of latent prostate cancer in urban middle-aged and elderly population in China,and to compare the accuracy of transperineal and transrectal approaches using pathological findings of autopsy prostate as the gold standard.Methods:This study consists of a single-center cross-sectional study and a diagnostic trial.Between 2014 and 2020,prostate specimens were collected from postmortem donors in Beijing,China.Twelve-core transperineal and transrectal biopsies were both conducted in autopsy prostate,followed by step sectioning of the whole gland with an interval of 2 mm-3 mm.Biopsy cores and whole-mount prostate samples were embedded and further sectioned to produce slices for pathological assessment.Boundaries of cancerous foci were outlined by software,and the volume and distribution of the tumors were derived by integrating information from each slice.Biopsy results were connected with tumor lesions and the difference in the diagnostic accuracy of transperineal and transrectal biopsy for tumors in different regions was analyzed.Results:A total of 204 prostate specimens were included in this study.The median age of the sample population was 83 years old.The prevalence of latent prostate cancer in this study was 35.6%,and was positively correlated with age(p for trend<0.05),Cases with International Society of Urological Pathology(ISUP)grade group 2-5 accounted for 41.1%(30/73),5.5%(4/73),1.4%(1/73),and 15%(11/73)of positive cases,respectively,and cases with index tumor volume>0.5 ml accounted for 21.9%(16/73)of positive cases.Seven cases presented with extraprostatic extension.A positive correlation between the total tumor volume and its ISUP grade group was observed(Kendall's tau-b=0.719,p<0.001).The distributions of all tumors in the anterior and posterior parts of the prostate were not significantly different,while the proportion of high-grade tumors was higher in the anterior part than in the posterior part(p=0.028).And the proportion of peripheral zone tumors was significantly higher than that of central zone tumors(p<0.001).Vertically,the positive rate was significantly higher at the apex of the prostate than at the base(p<0.001).The positive rate was highest in area 5 mm-11 mm above the apex and decreased the closer to the base.Combined biopsy had a higher sensitivity(46.6%)than transperineal(34.2%,p=0.004)or transrectal(35.6%%,p=0.008)biopsy alone.Poor agreement was observed between the two approaches,with no significant difference found in sensitivity for all cases(34.2%vs 35.6%,p=1.000)and tumors in different regions.The concordance of pathological findings with whole-mount prostate specimens was not significantly different between transperineal and transrectal biopsy(76.0%vs 69.2%,p=0.588).Conclusions:The prevalence of prostate cancer in the urban middle-aged and elderly population in China was 35.6%,which may have increased compared to early autopsy data in China.The volume of latent prostate cancer was significantly correlated with its ISUP grade group.The high proportion of prostate cancer with ISUP grade group 2 in our autopsy study suggests that ISUP grade group 2 alone may not be sufficient to determine clinical significance of the tumor,and should be combined with other characteristics such as the tumor volume and extraprostatic invasion for a comprehensive judgment.There was no significant difference in the distribution and pathological characteristics of prostate cancer in the horizontal quadrant.Vertically,the cancerous rate was higher in the area 5 mm-11 mm above the apex and was lower the closer to the base.No significant difference in the sensitivity and accuracy of transperineal versus transrectal biopsy was observed.The combined biopsy sensitivity was significantly higher than that of the transperineal and transrectal biopsy alone,suggesting the complementarity of the two approaches. |
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