Variability of α/β ratios for prostate cancer with the fractionation schedule: caution against using the linear-quadratic model for hypofractionated radiotherapy

Table 6 Parameters estimated with 95% CIs in different risks under different regimens of radiotherapy

Fractionation regimen	Risk group	K			α (Gy⁻¹)			α/β (Gy)
Fractionation regimen	Risk group	Estimate	95% CI	P	Estimate	95% CI	P	Estimate	95% CI BCa 95% CI^*	P
Conventional fractionation	Low risk	10.2	7.34–13.1	< 0.001	0.081	0.012–0.15	0.022	1.80	1.46–2.14	< 0.001
	Low risk	10.2	7.34–13.1	< 0.001	0.081	0.012–0.15	0.022	1.80	1.56–2.11	< 0.001
	Intermediate risk	8.20	6.85–9.56	< 0.001	0.073	0.041–0.10	< 0.001	2.29	2.12–2.47	< 0.001
	Intermediate risk	8.20	6.85–9.56	< 0.001	0.073	0.041–0.10	< 0.001	2.29	2.15–2.44	< 0.001
	High risk	4.31	2.80–5.83	< 0.001	0.023	− 0.0053–0.051	0.11	0.98	0.91–1.05	< 0.001
	High risk	4.31	2.80–5.83	< 0.001	0.023	− 0.0053–0.051	0.11	0.98	0.94–1.04	< 0.001
Moderate hypofractionation	Low risk	7.68	6.15–9.22	< 0.001	0.047	0.026–0.067	< 0.001	1.10	1.04–1.15	< 0.001
	Low risk	7.68	6.15–9.22	< 0.001	0.047	0.026–0.067	< 0.001	1.10	1.04–1.14	< 0.001
	Intermediate risk	6.62	5.85–7.38	< 0.001	0.044	0.032–0.057	< 0.001	1.34	1.25–1.44	< 0.001
	Intermediate risk	6.62	5.85–7.38	< 0.001	0.044	0.032–0.057	< 0.001	1.34	1.26–1.43	< 0.001
	High risk	4.93	4.00–5.87	< 0.001	0.011	0.0002–0.022	0.046	0.39	0.33–0.45	< 0.001
	High risk	4.93	4.00–5.87	< 0.001		0.0002–0.022	0.046	0.39	.34–0.45	< 0.001
SBRT^#	Low risk	− 4.81	− 16.3–6.64	0.41	− 0.14	− 0.66–0.39	0.61	− 10.7	− 12.6– − 8.7	< 0.001
	Intermediate Risk	10.7	3.16–18.2	0.005	0.27	− 0.019–0.56	0.067	25.6	21.6–29.6	< 0.001
	High risk	16.0	− 42.7–74.8	0.59	0.14	− 0.89–1.17	0.79	2.94	− 14.4–20.2	0.74

^*BCa 95% CI Bias-Corrected and accelerated intervals. We go a step further and calculate BCa intervals on the base of jackknife methods
^#The BCa intervals could not be drawn in the SBRT group due to the limited number of articles involved

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