Table 2.

Radiation Parameter Estimates for Oral/Pharyngeal Cancers excluding salivary gland cancer and Salivary Gland Cancer.

		Simple Linear ERRa	Linear ERR, adj. for smoking and alcohol	Linear ERR with effect modifier
Oral/pharynx cancer excluding salivary gland cancer, n=344	ERR/Gy	0.24 (−0.08, 0.72)b	0.26c (−0.08, 0.75)
	AICd	32.2	0
Salivary gland cancer, n=50	ERR/Gy	2.54 (0.69, 6.1)	--	0.72c (0.04, 3.20)
	Age at exposure [% change per decade]	--	--	−66% (−88%, −32%)
	AIC	8.3	--	0

^aExcess relative risk

^b95% Confidence Interval

^cRecommended model, Oral/pharynx cancer excluding salivary gland cancer; $\left(1+\beta d\mathrm{*}\mathrm{e}\mathrm{x}\mathrm{p}\left(\varphi I\left(K>4\right)\right)\right)\left(1+{ERR}_{smk}\right)\left(1+{ERR}_{drk}\right)$ and Salivary gland cancer; $1+\beta d\mathrm{*}\mathrm{e}\mathrm{x}\mathrm{p}\left({\delta }_2\left(\frac{e-30}{10}\right)+\varphi I\left(K>4\right)\right)$, where $d$ is radiation dose, $I$ is an indication function, $K$ is total shielded kerma, and, $e$ is age at exposure and $\beta ,\varphi$ and $\delta$ are regression coefficients.

^dAkaike Information Criterion (AIC) difference from model with lowest AIC