Table 2. Median biochemical recurrence-free time and five-year biochemical recurrence-free survival rates post-radical prostatectomy (RP) for each group of prostate cancer patients established by recursive partitioning analysis (RPA).

Group	No. of patients	Biochemical recurrence-free		Five-year biochemical recurrence-free survival rates
		Median (months)	95% CI	(%)
1	8	*	*	87.5
2	66	49.00	38.95 – 59.05	40.8
3	31	42.00	36.78 – 47.22	43.5
4	14	29.00	16.17 – 41.83	14.3
5	10	27.00	19.01 – 34.99	0.00
6	39	19.00	14.11 – 23.89	0.00

P = 0.000, using the Kaplan-Meier method to estimate the probability of survival and comparing the median biochemical recurrence-free time and five-year biochemical recurrence-free survival rates among the six groups of the patients after RP established by RPA through the log-rank test.

^*Because the recurrence rate of the group 1 has not dropped below 50 percent, the median time and 95% CI cannot be estimated.