Adaptive radiotherapy for locally advanced non-small cell lung cancer, can we predict when and for whom?

Figures & data

Table I. Baseline tumor characteristics.

	All	cCRT	sCRT
Pathology
adenocarcinoma	28	15	13
squamous	12	5	7
NOS	1	1	0
Location
peripheral	27	13	14
central	14	7	7
Stage
IIA	1	1	0
IIIA	24	12	12
IIIB	15	8	7
IV^a	1	0	1
T Stage
1	5	3	2
2	17	8	9
3	10	5	5
4	9	5	4
Tumor GTV_T_F1 (cm^3)
Median (range)	28.6	88.1	21.25
range	(1.9; 531.7)	(6.3; 531.7)	(1.9; 258.1)

^asolitary metastasis; curative approach.

cCRT, concurrent chemoradiotherapy; Central, planning target volume of the primary tumor lies adjacent to or invades the mediastinum; NOS, Not otherwise specified; Peripheral, all non-central tumors; sCRT, sequential chemoradiotherapy; T-stage, TNM classification 2009; Tumor GTV_T_F1 (cm³): Gross tumor volume (GTV) of the primary tumor (T) at fraction 1 (F1).

Table II. Mean percent changes in initial (F1) and final (F30) parameters with regards to location, histology and chemotherapy sequence.

		Tumor location			Histology^a			Chemotherapy mode
	Total group	Central	Peripheral	p-Value	Adeno carcinoma	Squamous cell carcinoma	p-Value	Sequential CRT	Concurrent CRT	p-Value
GTV
N	41	14	27		28	12		20	21
Mean volume decrease (%)	42.10	39.57	43.40	0.53	44.65	36.71	0.22	33.66	50.13	< 0.01
SD	18.19	17.17	18.88		19.19	15.71		17.57	15.14
Lung – GTV
N^b	40	14	26		28	11		20	20
Mean increase of V5 (%)	0.78	0.31	1.03	0.04	0.57	1.36	0.26	0.24	1.31	0.01
SD	1.33	0.47	1.57		0.81	2.14		0.31	1.71
Mean increase of V20 (%)	3.09	1.24	4.08	0.05	2.31	5.32	0.30	0.90	5.27	0.01
SD	5.54	1.52	6.62		3.38	9.00		1.02	7.20
Mean increase of V30 (%)	5.20	2.05	6.90	0.03	3.85	9.07	0.26	1.61	8.80	0.01
SD	8.92	2.19	10.64		5.73	14.08		1.94	11.51
Mean increase of MLD (%)	3.42	1.43	4.50	0.03	2.70	5.55	0.28	1.09	5.75	0.01
SD	5.42	1.72	6.39		3.97	8.03		1.42	6.84

^a1 patient was excluded due to lack of histology specification and ^b1 patient due to strong replacement of the tumor during treatment.

MLD, mean lung dose; SD, standard deviation; V5,20,30, percentage of lung receiving 5, 20 and 30 Gy, respectively.

Figure 1. Behavior of the GTV-T volume change during RT for cCRT and sCRT. cCRT, concurrent chemoradiotherapy; sCRT, sequential chemoradiotherapy.

Figure 2. Linear regression analysis. Graphic presentation demonstrating a linear relationship between the GTV-T-F1 and GTV-T-F30 for both groups (presented in a logarithmic scale).

Table III. The maximum possible gain of the dosimetric parameters.

		Maximum gain (%)
		Sequential CRT		Concurrent CRT
Groups	Reduction effect	0–50 cm^3	50–300 cm^3	0–100 cm^3	100–300 cm^3
V5
at fraction 5	0.86	0.02	−0.01^a	0.10	0.30
at fraction 10	0.71	0.03	0.04	0.11	0.42
at fraction 15	0.57	0.04	0.07	0.26	0.61
at fraction 20	0.43	0.05	0.10	0.21	0.61
at fraction 25	0.29	0.04	0.09	0.15	0.49
at fraction 30	0.14	0.02	0.09	0.08	0.27
V20
at fraction 5	0.86	0.07	−0.02^a	0.47	1.23
at fraction 10	0.71	0.13	0.14	0.52	1.62
at fraction 15	0.57	0.15	0.26	1.30	2.57
at fraction 20	0.43	0.18	0.36	1.07	2.41
at fraction 25	0.29	0.17	0.33	0.77	1.86
at fraction 30	0.14	0.10	0.30	0.41	1.01
V30
at fraction 5	0.86	0.13	−0.03^a	0.80	2.14
at fraction 10	0.71	0.22	0.29	0.88	2.83
at fraction 15	0.57	0.27	0.52	2.08	4.27
at fraction 20	0.43	0.32	0.69	1.69	4.08
at fraction 25	0.29	0.30	0.62	1.21	3.15
at fraction 30	0.14	0.17	0.57	0.64	1.72
MLD
at fraction 5	0.86	0.09	−0.02^a	0.48	1.40
at fraction 10	0.71	0.15	0.20	0.54	1.93
at fraction 15	0.57	0.18	0.37	1.22	2.74
at fraction 20	0.43	0.21	0.48	0.95	2.68
at fraction 25	0.29	0.20	0.44	0.69	2.12
at fraction 30	0.14	0.11	0.41	0.37	1.16
No. of cases from the original cohort		16	4	13	8

^aGTV might still in a growing phase.

bold = highest gain.

MLD, mean lung dose; V5,20,30: percentage of lung receiving 5, 20 and 30 Gy, respectively.