Urinary incontinence in prostate cancer patients treated with external beam radiotherapy.
OBJECTIVE
To describe the incidence of urinary incontinence among prostate cancer patients treated with external beam radiotherapy (RT) and to investigate associated risk factors.


METHODS
One thousand and hundred ninety-two patients with >or=24 months follow-up were the subjects of this series. All patients received between 50 and 72 Gy in 20-37 fractions (median 66 Gy/33#). Post-RT urinary incontinence was scored by direct patient interviewing according to the modified RTOG/SOMA scale: Grade 1--occasional use of incontinence pads, Grade 2--intermittent use of incontinence pads, Grade 3--persistent use of incontinence pads, and Grade 4--permanent catheter. Risk-factors investigated were: age, diabetes, TURP prior to RT, elapsed time from TURP to RT, clinical stage, RT dose and presence of Grade >or=2 acute GU and GI toxicity. Non-parametric, actuarial univariated (Kaplan-Meier) and multivariated tests (MVA, Cox regression) were performed.


RESULTS
Median follow-up for the group is 52 months (24-109). Thirty-four patients (2.9%) had incontinence prior to RT, which was more common in TURP patients (7.8% vs 1.6% P<0.001). These are excluded from further analysis. Fifty-seven patients (4.9%) developed Grade 1 incontinence, 7 (0.6%) Grade 2, and 7 (0.6%) Grade 3. There was no Grade 4 incontinence. Actuarial rates for Grade >or=1 and >or=2 incontinence at 5 years are 7 and 1.7%, respectively. Risk factors on MVA associated with the development of Grade 1 or worse incontinence are pre-RT TURP (5-year rates 10% vs 6%, P=0.026), presence of Grade >or=2 acute GU toxicity (5-year rates 11% vs 5%, P=0.002). Age, diabetes, clinical stage, elapsed time from TURP to RT, RT dose or fraction size, acute GI toxicity were not significant. Patients who underwent post-RT TURP or dilatation for obstructive symptoms (4.3%), were more likely to develop Grade 2-3 incontinence (5-year rate 8 vs 1.5%, P=0.0015).


CONCLUSIONS
Grade 2 or greater urinary incontinence is rare among patients who have been treated with external beam radiotherapy. Associated risk factors are pre-RT TURP and the presence of increased acute GU toxicity. Post-radiaton TURP increases the risk of incontinence five-fold.
Liu
Mitchell
M
Fraser Valley Centre, British Columbia Cancer Agency, 13750 96th Avenue, Surrey, BC, Canada.
Pickles
Tom
T
Berthelet
Eric
E
Agranovich
Alexander
A
Kwan
Winkle
W
Tyldesley
Scott
S
McKenzie
Michael
M
Keyes
Mira
M
Morris
James
J
Pai
Howard
H
D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D011832:Radiation Injuries / Q000453:epidemiology / Q000209:etiology*; D012307:Risk Factors; D012720:Severity of Illness Index; D020728:Transurethral Resection of Prostate; D014549:Urinary Incontinence / Q000453:epidemiology / Q000209:etiology*