Deep regional hyperthermia for the whole thoracic region using 8 MHz radiofrequency-capacitive heating device: Relationship between the radiofrequency-output power and the intra-oesophageal temperature and predictive factors for a good heating in 59 patients

Figures & data

Table I.  Patient characteristics.

Characteristic	Patients (n = 59)
Age (median, range)	62, 36–84
Gender
Men/women	58/1
Performance status
0/1/2/3	1/43/13/2
Cancer type
Lung cancer	50
NSCLC
Stage II/III/IV [11]	1/22/10
Recurrence	12
SCLC
Stage III/IV [11]	4/2
Oesophageal cancer	9
Stage II/III/IV [11]	2/2/2
Recurrence	3
Subcutaneous fat (median, range)
Ventral (mm)
Level of sternoclavicular articulation	4, 1–21
Level of tracheal bifurcation	7, 2–24
Level of nipple	9, 2–25
Level of cardia of stomach	7, 2–23
Dorsal (mm)
Level of sternoclavicular articulation	10, 2–25
Level of tracheal bifurcation	8, 2–15
Level of nipple	9, 2–24
Level of cardia of stomach	10, 2–24

NSCLC, non-small-cell lung cancer; SCLC, small-cell lung cancer.

Figure 1. All the thermal parameters, T_max (A), T_ave (B), T_min (C) and %T ≥ 41°C (D), of intra-oesophageal temperature were highly correlated with the median radiofrequency output power.

Table II.  Correlations between intra-esophageal thermal parameters and clinical characteristics.

	Tmax		Tave		Tmin		%T ≥ 41°C
Variables	r	p	r	p	r	p	r	p
Age	0.44	0.0005*	0.39	0.002*	0.32	0.01*	0.35	0.007*
Performance status	0.32	0.01*	0.27	0.04*	0.19	0.16	0.38	0.003*
Thickness of thorax
Level of sternoclavicular articulation	0.02	0.9	0.04	0.76	0.08	0.57	0.03	0.82
Level of tracheal bifurcation	0.07	0.59	0.12	0.36	0.23	0.08	0.12	0.37
Level of nipple	0.01	0.96	0.03	0.83	0.13	0.34	0.03	0.81
Level of cardia of stomach	0.1	0.43	0.12	0.36	0.19	0.16	0.1	0.47
Thickness of subcutaneous fat
Level of sternoclavicular articulation
Ventral	0.02	0.86	0.07	0.59	0.12	0.37	0.14	0.3
Dorsal	0.13	0.32	0.06	0.66	0.05	0.68	0.0	0.97
Level of tracheal bifurcation
Ventral	0.22	0.09	0.25	0.05	0.27	0.04*	0.22	0.09
Dorsal	0.2	0.12	0.27	0.04*	0.34	0.01*	0.12	0.36
Level of nipple
Ventral	0.22	0.09	0.26	0.05	0.3	0.02*	0.23	0.08
Dorsal	0.23	0.08	0.26	0.05	0.29	0.03*	0.2	0.14
Level of cardia of stomach
Ventral	0.26	0.05	0.3	0.02*	0.31	0.02*	0.24	0.06
Dorsal	0.18	0.18	0.23	0.09	0.31	0.02*	0.25	0.05
Maximum of ventral subcutaneous fat	0.19	0.15	0.24	0.07	0.27	0.04*	0.19	0.15
Maximum of doral subcutaneous fat	0.04	0.77	0.04	0.78	0.15	0.26	0.11	0.40
Maximum of all subcutaneous fat	0.07	0.59	0.02	0.91	0.13	0.31	0.06	0.68
Heating duration**	0.14	0.3	0.16	0.23	0.15	0.26	0.23	0.08
Median RF output power**	0.62	<0.0001*	0.66	<0.0001*	0.65	<0.0001*	0.63	<0.0001*

*p < 0.05.

**At the session of the intra-oesophageal temperature measurements.

RF, radiofrequency.

Figure 2. The correlations between the intra-oesophageal temperatures and clinical characteristics. (A) The patient age was inversely correlated with the T_max as thermal parameters of intra-oesophageal temperature. (B) The thicknesses of dorsal subcutaneous fat at the levels of the tracheal bifurcation was inversely correlated with T_min.

Table III.  Multivariate analyses by logistic regression to evaluate effects of clinical factors on the thermal parameters in patients with thoracic malignant tumour.

	Tmax: ≥ 43/<43		Tave: ≥42.5/<42.5		Tmin: ≥42/<42		%T ≥41°C: ≥70/<70
Patient characteristics	OR (95%CI)	p	OR (95%CI)	p	OR (95%CI)	P	OR (95%CI)	p
Age: ≥65/<65	1.1 (0.3–4.0)	0.85	1.2 (0.3–4.1)	0.82	1.5 (0.3–6.7)	0.61	1.2 (0.3–4.6)	0.76
Performance status: 0–1/2–3	4.8 (1.1–21.0)	0.04	3.8 (0.8–18.2)	0.1	–	–	6.2 (1.4–28.2)	0.02
Thickness of subcutaneous fat
Level of tracheal bifurcation
Ventral (mm): ≥10/<10	–	–	–	–	4.1 (0.4–50.0)	0.26	–	–
Dorsal (mm): ≥10/<10	–	–	1.2 (0.3–5.9)	0.81	NA	0.97	–	–
Level of nipple
Ventral (mm): ≥10/<10	–	–	–	–	2.4 (0.1–43.6)	0.55	–	–
Dorsal (mm): ≥10/<10	–	–	–	–	N.A.	0.97	–	–
Level of cardia of stomach
Ventral (mm): ≥10/<10	–	–	1.5 (0.2–4.0)	0.58	1.5 (0.1–16.8)	0.74	–	–
Dorsal (mm): ≥10/<10	–	–	–	–	1.1 (0.9–1.4)	0.33	–	–
Max. ventral subcutaneous fat	–	–	–	–	3.6 (0.2–52.6)	0.36	–	–
Median RF output (W): ≥1200/<1200	7.5 (2.1–26.8)	0.002	6.8 (1.6–28.5)	0.008	16.8 (2.1–136.3)	0.008	7.6 (2.0–28.1)	0.003

*At the session of the intra-oesophageal temperature measurements.

OR, odds ratio; CI, confidence interval; NA, not available.

Sobin LH, Witterkind CH. International Union Against Cancer. TNM Classification of Malignant Tumours, 5th edn. (Japanese edn.). Tokyo, Japan: Kinbara, 1997.

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