Results
During the study period, 13 patients (10 male), aged 9 months to 4 years (median 23 months), with BP-RMS were deemed suitable for CS-BT. Relevant clinical background was present in 2 patients: neurofibromatosis type 1 and high-grade vesico-ureteric reflux (VUR). All presented with localised fusion-negative embryonal BP-RMS (2 botyroid subtype), measuring a median 43mm (23-140mm) in cranio-caudal axis on MRI at diagnosis.
Local control was by PC+BT in three, PEP+BT in four and BT alone in six patients. One patient underwent oophoropexy before brachytherapy. For PC+BT, one third of the bladder was excised in one and one fifth of the bladder in two. The lymph nodes sampled confirmed N0 status.
Follow-up was available for all to a median 3½ years (range 1¾-7 years) from diagnosis. No recurrence or relapse occurred. At a median age of 6 years (range 4-9 years), the median (range) bladder capacity was 86% (47%-144%) of that expected for age, including 75% (74-114%) after PC compared to 97% (47%-144%) for other CS-BT patients (p=0.700). Maximum flow rates (Qmax) were 8 to 26ml/sec. There was no significant PVR in all but the VUR-patient with volumes after micturition of 20% the total voided volume.
Invasive video-urodynamic studies were performed in 2 patients who developed complications after treatment. In the patient with pre-existing VUR, this recorded a stable, compliant system with free vesico-ureteric reflux and normal voiding pressures. On extended clamping of the supra-pubic catheter, however, a decompensated picture emerged and a refluxing ureterostomy was created to optimise the safety of the upper tracts. The other patient developed a urethral stricture with a stable compliant bladder but high voiding pressures and low flows on urodynamics; a Mitrofanoff channel was formed for clean intermittent catheterisation. He is dry by day on anticholinergic medication and on free urinary drainage overnight.
The remaining eleven patients are dry by day (Table 1); five with continuous or intermittent assistance of anticholinergic medication for urinary urgency. At night, three patients are enuretic at ages 5, 5 and 9 years; all received BT alone and bladder capacity was assessed at 56%, 120% and 75% of EBCA at last review. Urinary ultrasound scans showed no hydronephrosis in all except one (BT alone) with unilateral mild hydronephrosis (antero-postero-pelvic diameter 12 mm).
No relationship was observed between the radiation dose to the bladder (2cm3 EQD2) and the assessed bladder capacity (Figure 1), p=0.535. 2cm3EQD2 radiation doses (Table 2) to the bladder were similar for those prescribed anticholinergic medication for urinary urgency (median 191.79Gy, range 61.65-406.17Gy) as compared to those without urgency (median 152.84Gy, range 36.56-217.98Gy), p=0.107. Likewise, no difference in 2cm3 EQD2to the bladder was observed between those enuretic (median 154.38Gy, range 61.65-217.98Gy) and those dry at night (median 156.56Gy, range 36.56-406.17Gy), p=1.000. Nor was a patterns observed in the 0.1cm3 EQD2 to the urethra for urgency (median 64.79Gy vs 72.14Gy, ranges 54.59-82.78Gy vs 60.52-222.15Gy), p=0.143; or enuresis (median 64.65Gy vs 71.65Gy, ranges 68.51-72.14Gy vs 54.59-222.15Gy), p=0.540.