Output-limiting symptoms induced by radiofrequency hyperthermia. Are they predictable?

Figures & data

Table 1. Characteristics of patients’ physical status with and without output-limiting symptoms.

	Complication (−)	±SE	Complication (+)	±SE	p-value
Age	68.0	1.7	64.8	1.5
Girth of abdomen (cm)	80.5	2.6	80.3	1.2
Body weight (kg)	52.3	2.3	57.8	1.4	0.05
Height (cm)	157.5	3.1	162.3	1.2
Body mass index	21.3	0.3	22.1	0.4
Internal organs fat area (cm^2)	56.5	12.9	93.4	7.8
Total fat area (cm^2)	138.9	29.4	183.9	13.0
Subcutaneous fat area (cm^2)	82.3	17.0	92.0	6.5
Thickness of the fat of the abdominal wall (mm)	11.3	1.9	15.3	0.9	0.028
Body surface area (m^2)*	1.5	0.0	1.6	0.0

*DuBois

Table 2. Results of multiple regression analysis in patients receiving abdominal irradiation with and without standardised power escalation principles.

		B	β	Adjusted R^2	p	Tolerance	VIF
With standardised power escalation principles
(Constant)		967.995			<0.001
Thickness of the fat of the abdominal wall		−17.155	−0.822	0.986	<0.001	0.958	1.044
Initial time an output- limiting symptom occurred		6.162	0.413		<0.001	0.958	1.044
Without standardised power escalation principles
(Constant)		944.832			<0.001
Thickness of fat of the abdominal wall		−15.826	−0.673	0.905	<0.001	0.848	1.179
Initial time an output-limiting symptom occurred		5.721	0.462		<0.001	0.848	1.179

VIF, variance inflammation factor

Figure 1. Incidence of output-limiting symptoms during five RF treatments. Patients with standardised power escalation principles developed output-limiting symptoms only once during five treatments, while those without standardised power escalation principles developed several output-limiting symptoms during five treatments.

Figure 2. Relationship between the observed and expected initial irradiation output at which output-limiting symptoms occurred in patients receiving abdominal irradiation with standardised power escalation principles, in watts.