Obstructive urination problems after high-dose-rate brachytherapy boost treatment for prostate cancer are avoidable

Results of univariate logistic regression analysis of association between deterioration of obstructive urination problems and treatment factors in Ljubljana Institute of Oncology study of late toxicity after high-dose-rate brachytherapy boost treatment for prostate cancer

Risk factor		Ntot	Ndet/Ncat (%)	OR	95 % C.I. limits for OR		p-value
					Lower	Upper
Nimplanted needles		71		0.89	0.71	1.11	0.305
Planning imaging	CT	71	3/25 (12.0%)	1.00
	MRI		10/46 (21.7%)	2.04	0.51	8.22	0.317
Ninterventions	1	71	10/63 (15.9%)	1.00
	2+		3/8 (37.5%)	3.18	0.65	15.48	0.152
PTV1 (ml)		70		1.03	0.99	1.07	0.149
D100PTV1 (Gy)		71		1.08	0.76	1.53	0.656
D90PTV1 (Gy)		71		0.93	0.68	1.28	0.673
D100PTV2 (Gy)		70		0.99	0.75	1.31	0.941
Vurethra (ml)		70		1.22	0.55	2.74	0.626
D-MEANurethra (Gy)		70		1.06	0.84	1.35	0.629
D90urethra volume (Gy)		71		1.18	0.95	1.47	0.145
D10urethra volume (Gy)		70		1.07	0.87	1.31	0.521
D1urethra volume (Gy)		71		1.03	0.86	1.22	0.780
Androgen deprivation	< 12 months	69	2/9 (22.2%)	1.00
	≥ 12 months		11/60 (18.3%)	0.79	0.14	4.31	0.781

Results of univariate logistic regression analysis of association between deterioration of obstructive urination problems and patients’ characteristics in Ljubljana Institute of Oncology study of late toxicity after high-dose-rate brachytherapy boost treatment for prostate cancer

Risk factor		Ntot	Ndet/Ncat (%)	OR	95 % C.I. limits for OR		p-value
					Lower	Upper
Age		70		1.05	0.94	1.17	0.372
Hypertension	No	69	5/32 (15.6%)	1.00
	Yes		7/37 (18.9%)	1.26	0.36	4.44	0.719
Diabetes	No	68	12/62 (19.4%)	NA
	Yes		0/6 (0.0%)	NA	NA	NA	0.581*
Hyperlipidemia	No	68	8/52 (15.4%)	1.00
	Yes		4/16 (25.0%)	1.83	0.47	7.14	0.382
CVI	No	69	10/62 (16.1%)	1.00
	Yes		2/7 (28.6%)	2.08	0.35	12.26	0.418
Coronary insufficiency	No	69	8/54 (14.8%)	1.00
	Yes		4/15 (26.7)	2.09	0.53	8.22	0.291
Anticoagulation treatment	No	69	6/52 (11.5%)	1.00
	Yes		6/17 (35.5%)	4.18	1.13	15.48	0.032

Results of multivariate logistic regression analysis of association between deterioration of obstructive urination problems and selected treatment factors and patients’ characteristics in Ljubljana Institute of Oncology study of late toxicity after high-dose-rate brachytherapy boost treatment for prostate cancer (N = 68)

Risk factor		OR	95% C.I. limits for OR		p
			lower	upper
PTV1 (ml)		1.02	0.98	1.07	0.292
D90urethra volume (Gy)		1.23	0.96	1.57	0.099
Anticoagulation treatment	No	1.00
	Yes	4.86	1.21	19.61	0.026

Characteristics of dosimetric parameters of high-dose-rate brachytherapy in Ljubljana Institute of Oncology study of late toxicity after high-dose-rate brachytherapy boost treatment for prostate cancer

Dosimetric parameter	Minimum	Maximum	Mean±SD
PTV1	18 ml	95 ml	37.6 ± 14.8 ml
D100PTV1	8.3 Gy	17.1 Gy	11.8 ± 1.9 Gy
D90PTV1	13.4 Gy	24.6 Gy	19.2 ± 2.0 Gy
D100PTV2	12.8 Gy	23.7 Gy	17.3 ± 2.1 Gy
Vurethra	1.2 ml	4.0 ml	1.9 ± 0.8 ml
D-MEANurethra	14.4 Gy	26.1 Gy	19.0 ± 2.6 Gy
D90urethra volume	7.5 Gy	18.9 Gy	13.2 ± 2.9 Gy
D10urethra volume	17.8 Gy	31.1 Gy	23.1 ± 2.7 Gy
D1urethra volume	17.3 Gy	36.0 Gy	24.5 ± 3.4 Gy

Questions addressing obstructive urination problems in Ljubljana Institute of Oncology questionnaire about adverse health effects of radiation therapy

Question	Possible answers
Did you have a sensation of not emptying your bladder in the previous month	Yes/No
Did you find stopping and starting again several times when you urinated in the previous month	Yes/No
Did you have weak urinary stream in the previous month	Yes/No
Did you have to strain to start urination in the previous month	Yes/No
	Occasionally
	At least once a week
If you had any of the problems, how often did they occur	Daily
	At every urination
	No problem
	Very small problem
How big were these problems for you	Small problem
	Moderate problem
	Big problem
Did you have to get urinary catheter in the last half of the year	Yes/No
Were you operated because of the mentioned problems	Yes/No
Did you still have urinary catheter	Yes/No

Prevalence rates of alteration of obstructive urination problems in Ljubljana Institute of Oncology study of late toxicity after high-dose-rate brachytherapy boost treatment for prostate cancer

Year of follow-up	N	Major improvement	Minor improvement	No change	Minor deterioration	Major deterioration
2nd year	80	1 (1.3%)	10 (12.5%)	57 (71.3%)	12 (15.0%)	0 (0%)
3rd year	71	1 (1.4%)	11 (15.5%)	51 (71.8%)	8 (11.3%)	0 (0%)
4th year	45	2 (4.4%)	7 (15.6%)	31 (68.9%)	4 (8.9%)	1 (2.2%)
5th year	25	0 (0%)	6 (24.0%)	16 (64.0%)	3 (12.0%)	0 (0%)