TABLE 1:

Differences in slopes between patients who received reduced (23.4 Gy) or conventional (36–39.6 Gy) craniospinal irradiation doses

CC Region	CSI Dose (Gy)	Slope*	Significance†
Total	Reduced	−20.0	0.52
	Conventional	−16.0
Rostrum	Reduced	0.2	0.29
	Conventional	1.4
Genu	Reduced	−0.1	0.20
	Conventional	−4.6
Rostral body	Reduced	−2.4	0.55
	Conventional	−1.2
Anterior midbody	Reduced	−1.6	0.81
	Conventional	−1.2
Posterior midbody	Reduced	−1.4	0.98
	Conventional	−1.4
Isthmus	Reduced	−2.0	0.75
	Conventional	−2.2
Splenium	Reduced	−7.0	0.17
	Conventional	−2.4

Note.—CC indicates corpus callosum; CSI, craniospinal irradiation.

^*Change in CC size per year since start of CSI (mm²).

^†Testing H₀: slope (reduced) = slope (conventional); P < .05, two-tailed test.