Table 3.

Independent risk factors

Characteristics	p Value	Odds ratio	95% confidence interval
Excessive blood supply	0.024	2.281	1.116–4.666
Location at or cephalad to S2	0.021	3.840	1.225–12.032
Tumor volume greater than 200 cm3	0.001	3.381	1.629–7.020
Anterior and posterior approach	0.054	3.047	0.980–9.476