Efficacy Of LDR-BT Combined With MAB In The Treatment Of Prostate Cancer And Construction Of A Nomogram For PSA Progression

Objective:To evaluate the clinical efficacy of ¹²⁵I brachytherapy（BT）combined with Maximum androgen blockade（MAB）treatment in intermediate to high risk localized and metastatic prostate cancer（mPCa）,to investigate the risk factors affecting PSA Progression after treatment and to construct a clinical prediction model.Method:A retrospective analysis was conducted on 3 19 patients with intermediate to high-risk limited and metastatic prostate cancer admitted to the Department of U the Second Hospitrology ofal of Soochow University from April 2012 to April 2022.154 patients in the ¹²⁵I brachytherapy combined with MAB treatment group,median age 81.0（76.0-84.0）years,follow-up time 47.4（23.4-65.6）months;and 165 cases in the MAB treatment group,median age 79（73.0-83.0）years,follow-up time 43.6（25.4-66.6）months.A propensity score-matched（PSM）cohort analysis was applied to adjust for potential bias and Kaplan-Meier survival curves were plotted to compare the prognosis of patients in the two groups.ROC curves were used to assess the diagnostic efficacy of the included indicators influencing the occurrence of PSA Progression after combination therapy and to calculate cut-off values.Independent risk factors influencing the occurrence of PSA Progression after combination therapy were screened by univariate and multivariate COX regression,and a Nomogram was constructed and validated internally.Results:BT combined with MAB treatment was superior to the MAB-only group in terms of Overall survival（OS）,Cancer-specific survival time（CSS）,Biochemical relapse-free survival time（bRFS）,and Clinical relapse-free survival time（cRFS）,and the combined treatment group also had better biochemical control in T2/T1,T3/T4,N0,N1,M0,M1,WHO/ISUP1-4 clinical subgroups and in patients with intermediate-risk localized,clinically localized,localized,and metastatic prostate cancer.Univariate COX regression showed that T-stage,N-stage,Gleason score,PI-RADS score,biopsy positive pin count rate,nPSA,TnPSA,RBC distribution width（CV）,RBC distribution width（SD）,Haemoglobin,Alkaline phosphatase,C-reactive protein.Alkaline phosphatase/albumin,C-reactive protein/albumin were the most important factors affecting PSA Progression,and multivariate COX regression results showed that PI-RADS score,nPSA,TnPSA,and Alkaline phosphatase were independent risk factors for PSA Progression.The area under the curve（AUC）of the four combined indicators for predicting post-treatment PSA Progression was 0.924,with a sensitivity of 83.33%and specificity of 93.75%,which had better predictive value than each single indicator.The nomogram for predicting PSA Progression after combined treatment was constructed using independent risk factors,with a C-index（C-index）of 0.90 and a high degree of discrimination.The calibration curve showed that the model had high accuracy.Conclusion:1.The results showed better efficacy of ¹²⁵I seed implantation combined with MAB in intermediate to high risk localized and metastatic prostate cancer compared to MAB alone,with better OS.CSS.bRFS,cRFS.and also excellent biochemical control in different clinical subgroups and risk levels.2.The Nomogram was constructed based on the independent risk factors（PI-RADS score,nPSA.TnPSA.ALP）affecting PSA Progression after combination therapy are well differentiated and calibrated,and can effectively predict the risk of PSA Progression after combination therapy and guide physicians’ clinical decision making,which has certain clinical application value.