Factors predicting for postimplantation urinary retention after permanent prostate brachytherapy

Area of Science:

• Urology
• Radiation Oncology
• Medical Physics

Background:

• Urinary retention is a known complication following permanent interstitial radioactive seed implantation for prostate cancer.
• Predictive factors for this complication remain incompletely understood, necessitating further investigation.

Purpose of the Study:

• To identify factors associated with urinary retention requiring catheterization in prostate cancer patients treated with permanent interstitial seed implantation.

Main Methods:

• A retrospective analysis of 91 prostate cancer patients treated with permanent seed implantation between 1996 and 1999.
• Evaluation of pre-implant ultrasound and post-implant CT volume studies, along with patient records.
• Statistical analysis using logistic regression and chi2 to assess predictors such as clinical stage, Gleason score, prostate volume, and treatment parameters.

Main Results:

• 12% of patients (11 of 91) experienced urinary obstruction requiring catheterization.
• Significant predictors for urinary retention included the total number of needles used, pretreatment prostate ultrasound volume, planning ultrasound target volume (PUTV), and posttreatment CT volume.
• Patients requiring more than 33 needles had a significantly higher obstruction rate (22.5%) compared to those using 33 or fewer (3.9%).
• Prostate volumes greater than 35 cc were associated with a higher incidence of obstruction (22%) compared to smaller volumes (7%).

Conclusions:

• The number of needles used during the procedure and prostate volume are significant predictors of urinary retention after permanent prostate seed implantation.
• These findings suggest that procedural factors like needle count and patient anatomy (prostate size) play a crucial role in post-treatment urinary complications.