Table 1.

Study Participant Demographic and Clinical Characteristics

Characteristic	CTCs < Five per 7.5 mL (n = 104)		CTCs ≥ Five per 7.5 mL (n = 108)		P
	No.	%	No.	%
Race					.564
Black	15	0.14	11	0.10
Other	4	0.04	6	0.06
White	85	0.82	91	0.84
Type of progression					1.000
Measureable/evaluable	87	0.84	90	0.83
PSA only	17	0.16	18	0.17
Bisphosphonate use					.100
No	42	0.40	31	0.29
Yes	62	0.60	77	0.71
Worst pain (Brief Pain Inventory score)					.034
< 4	67	0.64	53	0.49
≥ 4	37	0.36	55	0.51
Extraskeletal metastasis					.977
No	46	0.44	49	0.45
Yes	58	0.56	59	0.55
Performance status					.224
0	55	0.53	49	0.45
1	46	0.44	49	0.45
2	3	0.03	9	0.08
3	0	0.00	1	0.01
Missing	0	0.00	0	0.00
Gleason score					.914
< 7	11	0.11	11	0.10
7	29	0.28	33	0.31
> 7	61	0.59	61	0.56
Missing	3	0.03	3	0.03
Age at registration, years					.406
Mean	70		69
SD	8		10
Median	69		68
Interquartile range	63-76		62-75
Baseline PSA, ng/mL					.004
Mean	99		320
SD	221		761
Median	33		103
Interquartile range	13-109		49-335
Liver disease					.028
No	98	0.94	91	0.84
Yes	6	0.06	12	0.11
Unknown	0	0.00	5	0.05
Hemoglobin, g/dL					.001
Mean	13		12
SD	1		2
Median	13		12
Interquartile range	12-14		11-13
Alkaline phosphatase					< .001
Mean	121		354
SD	87*		406
Median	97		208
Interquartile range	74-132		128-420

Abbreviations: CTC, circulating tumor cell; PSA, prostate-specific antigen; SD, standard deviation.

^*For 103 patients.