Evaluation of the "Quadrella" at 3 years: New index to assess functional and oncological performance specific to prostate brachytherapy

Abstract

Purpose: "Quadrella" index has been recently developed to assess oncological and functional outcomes after prostate brachytherapy (PB). We aimed to evaluate this index at 1, 2, and 3 years, using validated questionnaires, assessed prospectively.

Methods and materials: From 08/2007 to 01/2013, 193 patients underwent ¹²⁵Iodine PB for low-risk or favorable intermediate-risk prostate adenocarcinoma. Inclusion criteria were as follows: no incontinence (International Continence Society Index initial score = 0) and good erectile function (International Index of Erectile Function-5 items: >16). One hundred patients were included (mean age: 64 y). Postimplantation intake of phosphodiesterase inhibitors was not considered as failure. The "Quadrella" index was defined by the absence of biochemical recurrence (Phoenix criteria), significant erectile dysfunction (ED) (Index of Erectile Function-5 items: >16), urinary toxicity (UT) (International Prostate Score Symptom [IPSS] <15 or IPSS> 15 with ΔIPSS <5), and rectal toxicity (RT) (Radiation Therapy Oncology Group = 0).

Results: At 12 months, 90 patients were evaluable: 42/90 (46.7%) achieved Quadrella. The main criteria for failure were as follows: ED in 77.1% (37/48) of cases, RT in 20.8% (10/48) of cases, and UT in 12.5% (9/57) of cases. At 24 and 36 months, 59.3% (48/81) and 61.1% (44/72) of patients achieved Quadrella, respectively. The main cause of failure was ED in 69.7% (23/33) and 85.7% (24/28) of cases, while RT was involved in 21.2% (7/33) and in 3.6% (1/28) of cases, and UT in 9.1% (3/33) and 3.6% (1/28) of cases. Only one case of biochemical recurrence was observed (i.e., 1/28 = 3.6% at 3 y).

Conclusions: The Quadrella can be used at 1, 2, and 3 years after PB. It allows to take into account the urinary and RT specific to PB. ED was the main cause of failure. This index will be useful to assess midterm and long-term results.

Keywords: Combined outcome; Erectile dysfunction; Functional outcome; Gastrointestinalis toxicity; Genitourinary toxicity; Postoperative evaluation; Prostate brachytherapy; Prostate cancer; Quality of life; Toxicity.