Outcomes in men with large prostates (≥ 60 cm³) treated with definitive proton therapy for prostate cancer

Figures & data

Table I. Patient characteristics.

Characteristics	Value
No. of patients	186
Age
≥ 60 years	95.8%
< 60 years	4.2%
Race
White	92.1%
Black	7.9%
Pre-PT obstructive symptom management
None	49.0%
TURP	9.7%
Alpha blocker	32.0%
Avodart	10.8%
Proscar	4.2%
Saw palmetto	11.8%
Risk stratification
Low	46.0%
Intermediate	37.0%
High	17.0%
Median PT dose	78 CGE (58–82 CGE)
ADT
Total	n = 33 (18%)
Neoadjuvant	n = 24 (13%)
Cytoreduction	n = 14 (7.5%)

ADT, androgen-deprivation therapy; PT, proton therapy; TURP, transurethral resection of the prostate.

Table II. Univariate (Kaplan-Meier and Log Rank Test) analysis of factors affecting Grade 3 + genitourinary (GU) toxicities and Grade 2 + gastrointestinal (GI) toxicities.

Factor	GU Grade 3+	GI Grade 2+
Age > 70 years	0.6098	0.2951
Prostate size > 76 cm^3	0.0188	0.7954
Pretreatment IPSS > 15	0.415	0.3038
Pretreatment PSA	0.1833	0.3022
Risk category	0.9752	0.3811
Total dose > 78 CGE	0.6751	0.0082
ADT at any time point	0.0784	0.3142
Neoadjuvant ADT	0.3589	0.6981
Pretreatment TURP	<0.0001	0.1903
Pretreatment alpha blocker use	0.0376	0.7815
Pretreatment finasteride use	<0.0001	0.5201
Combination of pretreatment alpha blockers, Avodart, and Proscar	0.0009	0.9999

ADT, androgen-deprivation therapy; CGE, Cobalt Gray equivalent; IPSS, International Prostate Symptom Score; PSA, prostate-specific antigen; TURP, transurethral resection of the prostate.

bold highlights statistically significant data.

Table III. Multivariate analysis.

Multivariate analysis	GU 3+	HR	HR lower	HR upper	GI 2+	HR	HR lower	HR upper
Prostate size > 76 cm^3	0.082	0.3	0.1	1.2	0.4925	1.4	0.5	3.9
Total dose > 78 CGE	0.394	0.4	0.0	3.5	0.0142	3.8	1.3	10.8
Neoadjuvant ADT	0.4268	0.5	0.1	2.6	0.6912	1.5	0.2	11.5
Pretreatment alpha blockers/5α reductase inhibitors	0.0065	0.1	0.0	0.6	0.8678	1.1	0.4	3.0
Pretreatment IPSS > 15	0.1057	0.4	0.1	1.2	–	–	–	–
TURP	0.0002	0.1	0.0	0.4	–	–	–	–
Blood thinners	–	–	–	–	0.7251	1.2	0.4	3.3

ADT, androgen-deprivation therapy; CGE, Cobalt Gray equivalent; HR, hazard ratio; IPSS, International Prostate Symptom Score; TURP, transurethral resection of the prostate.