MRI-Derived Prostate Shape Ratio as an Independent Predictor of Intraoperative Blood Loss during Robotic-Assisted Radical Prostatectomy

Tarapon Setthawong; Kun Sirisopana; Surawach Piyawannarat; Yada Phengsalae; Premsant Sangkum; Varagorn Jirajan; Chinnakhet Ketsuwan; Wisoot Kongchareonsombat

doi:10.33192/smj.v78i11.282728

Authors

Tarapon Setthawong, M.D. Division of Urology, Department of Surgery, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
Kun Sirisopana, M.D. Division of Urology, Department of Surgery, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
Surawach Piyawannarat, M.D. Division of Urology, Department of Surgery, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
Yada Phengsalae, M.Sc. Division of Urology, Department of Surgery, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
Premsant Sangkum, M.D. Division of Urology, Department of Surgery, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
Varagorn Jirajan, M.D. Division of Urology, Department of Surgery, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
Chinnakhet Ketsuwan, M.D. Division of Urology, Department of Surgery, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
isoot Kongchareonsombat, M.D. Division of Urology, Department of Surgery, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand

DOI:

https://doi.org/10.33192/smj.v78i11.282728

Keywords:

robotic prostatectomy, blood loss, prostate morphology, MRI, surgical complexity

Abstract

Objective: To evaluate whether MRI-derived prostate shape ratio (SR; width-to-length) predicts estimated blood loss (EBL) during RARP and to assess its interaction with prostate volume.

Materials and Methods: We retrospectively analysed 160 patients with clinically localised or locally advance prostate cancer who underwent standardised RARP between 2017 and 2022. SR was calculated from preoperative multiparametric MRI, and patients were stratified into SR ≤1 and SR >1 groups. Multivariable linear and logistic regression analyses were performed to identify predictors of EBL and high blood loss (HBL; EBL ≥300 mL). An interaction term between SR and prostate volume (<50 cm³ vs. ≥50 cm³) was included. Sensitivity analysis was performed after excluding patients who received neoadjuvant hormonal therapy (NHT).

Results: Median EBL was higher in patients with SR >1 than in those with SR ≤1 (300 vs. 150 mL; p < 0.001). SR >1 independently predicted increased EBL (β = +112.4 mL; 95% CI 58.1–166.7; p < 0.001) and HBL (AOR 3.18; 95% CI 1.64–6.15; p < 0.001). Prostate volume was also associated with higher EBL, whereas greater surgeon experience reduced blood loss. Sensitivity analysis excluding NHT-treated patients showed findings consistent with the primary analysis. A significant interaction between SR and prostate volume was observed (p = 0.018). In glands <50 cm³, SR >1 was associated with higher odds of HBL in the unadjusted subgroup analysis (OR 4.12; 95% CI 1.89–8.98).

Conclusions: MRI-derived prostate SR was associated with intraoperative blood loss during RARP after adjustment for measured covariates. Further validation is required to establish its incremental value beyond prostate volume.

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