Table 2.

The correlation coefficient (r) and P value for rectum.

Relevant factors r, P	VHR-CTV	Vsub-rectum 1	Vsub-rectum 2	Vsub-rectum 3	Vsub-rectum 4	Vsub-rectum 5
$\text{r}({\text{D}}_{2\text{c}{\text{m}}^3}/{\text{D}}_{\text{prescription}})$	0.40**	0.59**	0.37**	0.36**	-0.29*	-0.28*
$P({\text{D}}_{2\text{c}{\text{m}}^3}/{\text{D}}_{\text{prescription}})$	0.005	<0.001	0.009	0.009	0.028	0.033

**When the confidence (double test) is less than 0.01, the correlation is significant, *when the confidence (double test) is less than 0.05, the correlation is significant, the negative indicates that there is a negative correlation between the Vsub- rectum and ${\text{D}}_{2\text{c}{\text{m}}^3}/{\text{D}}_{\text{prescription}}$ of rectum.

Vsub-rectum, the volume of the sub-rectum.