(221) PREDICTORS OF INTRA CORPORAL TRIMIX DOSAGE IN PATIENTS POST-PROSTATE CANCER TREATMENT USING PENILE DOPPLER ULTRASOUND READINGS AND CLINICAL PARAMETERS

Abstract Introduction Intracorporeal injection (ICI) therapy is a well-established treatment for erectile dysfunction (ED), particularly after oral medications fail to produce satisfactory results. However, determining the optimal ICI dose can be challenging for patients, often leading to under dosing which results in suboptimal response or overdosing with an increased risk of priapism. Objective This study aims to explore whether pre-treatment clinical data and in-office penile Doppler ultrasound (PDU) parameters could guide ICI dosing for Trimix penile injections. Methods A retrospective chart review was done for patients with ED following prostate cancer treatment. 233 Patients who underwent PDU and then started a standard dose of Trimix ICI (Alprostadil 30mcg/ml, phentolamine 1 mg/ml, papaverine 10 mg/ml) with a minimum 6 months follow-up were included. Data regarding pre-treatment patients’ clinical parameters, PDU reading (dose of the procedure ICI, blood flow velocities, cavernosal artery diameter, plaques presence) and the initial and follow up doses of ICI Trimix (per unit, each 1 ml has 100 units) was retrieved. Pearson correlation coefficient was used to measure the linear correlation between the different variables of clinical parameters/PDU readings and the required dose of Trimix ICI at 3-6 months follow up visit. Results Table 1 presents the baseline clinical characteristics of the sample. Among the patients, 51.9% were hypertensive, 17.2% were diabetic. Additionally, 76.9% underwent radical prostatectomy or cystoprostatectomy, 24.5% had a history of radiation therapy, and 18% had undergone Androgen Deprivation Therapy. The required Trimix ICI dose during follow-up showed significant positive correlations with patient age (0.199, p = 0.003) and Hemoglobin A1c (HbA1c) levels (0.223, p = 0.04). Conversely, it exhibited a significant negative correlation with the initial clinical response (degree of erection) during clinic PDU/ICI (-0.04, P = 0.00) (Table 2). None of the PDU parameters correlated with the follow up Trimix dosage. Conclusions In patients with ED following prostate cancer treatment who require ICI therapy, the patient age, HbA1c and clinical response during clinic PDU/ICI can predict the required dose of ICI to induce a satisfactory erection. Using such clinical parameters can guide the urologists in prescribing the proper dose of ICI to achieve a satisfactory erection. Disclosure No.