Table 2.

Comparison of tumour control probability (TCP) values for planning and mean cone beam CT (CBCT) clinical target volume 2 (CTV₂) dose–volume histograms (DVHs) for all patients using decreasing CTV₂ to planning target volume 2 (PTV₂) margins

CTV2 to PTV2 margin (mm)	TCP (planning CTV2 DVH)	TCP (mean CBCT CTV2 DVH)	p-value (two-tailed)a	Mean CBCT TCP relative to original plan TCP (%)
5	81.8% (78.9–83.8)	82.0% (79.5–84.0)	0.009	0.3 (−1.1 to 1.0)
4	81.7% (78.7–83.8)	81.8% (79.2–83.9)	0.034	0.1 (−1.5 to 0.7)
3	81.9% (78.8–83.8)	81.9% (79.2–83.6)	0.272	0.2 (−2.0 to 0.7)

Data are represented as mean (range).

^aWilcoxon signed rank test.