Relationships between the changes of skin temperature and radiation skin injury

Figures & data

Figure 1. Acquirement of the lateral-view side mirrors and measurement of the changes in the difference of skin temperature (DST). (A and B) The range of imaging. (C–E) The calculation of the DST. DST_average/max=the average/maximum temperature (treated) the average/maximum temperature (control).

Table 1. Patient demographics and disease characteristics.

Characteristic	Grade	No. of patients (N = 41)	Percentage (%)
Age (years)	Median	45
	Range	28–67
BMI	Median	25.7
	Range	19.7–33.5
Breast size	A	7	17.1
	B	23	56.1
	C	11	26.8
Performance status (ECOG)	0	21	51.2
	1	20	48.8
T stage	T1	8	19.5
	T2	25	61.0
	T3	3	7.3
	T4	5	12.2
N stage	N1	15	36.6
	N2	15	36.6
	N3	11	26.8
AJCC stage^a	IIA	5	12.2
	IIB	10	24.4
	IIIA	13	31.7
	IIIB	2	4.9
	IIIC	11	26.8
Endocrine therapy	Yes	15	36.5
	No	26	63.5
Trastuzumab therapy	Yes	10	24.4
	No	31	75.6
Adjuvant chemotherapy	Before radiotherapy	41	100.0
	After radiotherapy	0	0
Surgery to	Right breast	21	51.2
	Left breast	20	48.8

^a The eighth American Joint Committee on Cancer (AJCC) TNM staging system was used.

Table 2. The patient-reported symptoms and temperature changed along with time.

							Week 6	Week 7
	Baseline	Week 1	Week 2	Week 3	Week 4	Week 5	(END 1)	(END 2)
Burning-feeling (mean ± SD)	0	0.024 ± 0.156	0.317 ± 0.521	0.780 ± 0.613	1.048 ± 0.669	1.150 ± 0.700	1.195 ± 0.401	1.073 ± 0.345
Week n vs. Week n − 1	NA	p = .323	p = .001	p < .001	p = .014	p = .210	p = .168	p < .001
Week n vs. baseline	NA	p = .323	p < .001	p < .001	p < .001	p < .001	p < .001	p < .001
Itching (mean ± SD)	0	0.049 ± 0.312	0.195 ± 0.401	0.634 ± 0.623	1.012 ± 0.711	1.350 ± 0.580	1.525 ± 0.599	0.976 ± 0.724
Week n vs. Week n − 1	NA	p = .323	p = .032	p < .001	p = .002	p = .001	p = .033	p < .001
Week n vs. baseline	NA	p = .323	p = .003	p < .001	p < .001	p < .001	p < .001	p < .001
Pulling (mean ± SD)	0	0.024 ± 0.156	0.146 ± 0.358	0.561 ± 0.502	0.927 ± 0.469	1.075 ± 0.474	1.100 ± 0.591	1.049 ± 0.545
Week n vs. Week n − 1	NA	p = .323	p = .023	p < .001	p < .001	p = .012	p = .711	p = .421
Week n vs. baseline	NA	p = .323	p = .012	p < .001	p < .001	p < .001	p < .001	p < .001
Pain (mean ± SD)	0	0	0	0.171 ± 0.381	0.366 ± 0.488	0.550 ± 0.597	0.659 ± 0.693	0.390 ± 0.494
Week n vs. Week n − 1	NA	na	na	p = .007	p = .010	p = .019	p = .323	p = .001
Week n vs. baseline	NA	na	na	p = .007	p < .001	p < .001	p < .001	p < .001
Tenderness (mean ± SD)	0	0	0	0	0	0.050 ± 0.221	0.050 ± 0.221	0.049 ± 0.218
Week n vs. baseline	NA	na	na	na	na	p  =  0.160	p  =  1.000	p  =  1.000
Week n vs. Week n − 1	NA	na	na	na	na	p  =  0.160	p  =  0.160	p  =  0.160
DSTaverage (mean ± SD)	−0.039 ± 0.477	0.207 ± 0.517	0.434 ± 0.498	0.4829 ± 0.55	0.661 ± 0.517	0.818 ± 0.625	1.007 ± 0.769	0.936 ± 0.792
Week n vs. Week n − 1	NA	p = .021	p = .003	p = .495	p = .092	p = .017	p = .798	p = .262
Week n vs. baseline	NA	p = .021	p < .001	p < .001	p < .001	p < .001	p = .001	p = .014
DSTmax (mean ± SD)	−0.012 ± 0.448	0.217 ± 0.494	0.427 ± 0.448	0.488 ± 0.529	0.634 ± 0.603	0.705 ± 0.680	1.036 ± 0.687	0.754 ± 0.875
Week n vs. Week n − 1	NA	p = .027	p = .008	p = .425	p = .104	p = .128	p = .099	p = .355
Week n vs. baseline	NA	p = .027	p < .001	p < .001	p < .001	p < .001	p < .001	p = .023

Week 1–7: first to seventh week after the start of radiotherapy; END1–2: first to second week after the end of radiotherapy; Week n vs. Week n − 1: comparison of symptom scores between in the n weeks and in n − 1 weeks after radiotherapy; Week n vs. baseline: comparison of symptom scores between in n weeks after radiotherapy and before radiotherapy.

Figure 2. The correlation of the difference of skin temperature and dermatitis score. (A) A representative case with thermography and photograph every week. The color was a presentation of the surface temperature in thermography from 22.7 to 37.9 °C. (B) DST gradually increased with the progress of radiotherapy and peaked at the first week after the end of radiotherapy. (C) With the progress of radiotherapy, the RSI became more severe. The proportion of RSI Grade 2 was the highest at 1 week after the end of radiotherapy. Combined with the above three parts, it can be intuitively found that the severity of RSI is positively correlated with skin temperature changes.

Figure 3. Receiver–operator curve of the difference in temperature as a predictor of future RSI and the tendency chart of DST according RTOG grade. (A and C) The ROC curve of DSTW_average and DSTW_max, respectively (p = .027 and 0.044). (B and D) The change of difference in average and maximum temperature based on the maximum dermatitis score groupings (Grade 1 or Grade 2), respectively. The slope value of temperature at the second week end compared with the first week was significant increase in a higher toxicity group.