Table 2.

Multivariate linear regression model with IRS values and all clinical variables as covariates in 143 patients.

Coefficients	Estimate	Std. error	t-value	Pr(>|t|)
(Intercept)	39.123	5.804	6.740	4.86e-10	***
Tumor type—HNSCC vs. breast cancer	−1.023	2.967	−0.345	0.730
Age in years	0.005	0.087	0.060	0.952
Dermatitis radiation—G1 vs. G0	3.761	2.216	1.697	0.092	□
Dermatitis radiation—G2 vs. G0	−0.072	3.328	−0.022	0.982
Dermatitis radiation—G3 vs. G0	−4.401	4.623	−0.952	0.342
Pain—G1 vs. G0	−0.317	2.177	−0.146	0.884
Pain—G2 vs. G0	−2.143	3.836	−0.559	0.577
Pain—G3 vs. G0	1.216	6.050	0.201	0.8410
Pruritus—G1 vs. G0	−1.764	2.324	−0.759	0.449
Pruritus—G2 vs. G0	2.994	3.558	0.841	0.401
Pruritus—G3 vs. G0	6.988	5.370	1.301	0.195
Fatigue–G1 vs. G0	−4.265	1.960	−2.176	0.03	*

IRS is considered as continuous value and clinical variables are those defined at the completion of RT treatment (t1). p-value of the model is 0.2217.

^***p-value < 0.001,

^*p-value < 0.05,

^□p-value < 0.1.