Clinical implications of dose to functional lung volumes in the trimodality treatment of esophageal cancer

Figures & data

Figure 1. Definition of functional lung volumes.

A + B: Functional lung mapping (A + B) giving shape to the functional lung volume (FLV);

C + D: Projection of the treatment plan isodoses in relation to the FLV.

Table 1. Comparison of patient baseline characteristics between patients with and without pulmonary complications.

		Postoperative pulmonary complications
		No (n = 39)		Yes (n = 12)
Patient Characteristics		N	%	N	%	p
Sex	Male	34	87%	10	83%	.735
	Female	5	13%	2	17%
ECOG	0	21	54%	5	42%	.401
	1	16	41%	5	42%
	2	2	5%	2	17%
Charlson Comorbidity Index	≤ 1	28	72%	8	67%	.733
	> 1	11	28%	4	33%
Smoking	Never	2	5%	2	17%	.592
	Active	12	31%	4	33%
	Stopped < 1 year	5	13%	1	8%
	Stopped > 1 year	20	51%	5	42%
		Mean (SD)		Mean (SD)
Age diagnosis		64 (10)		68 (8)		.203
BMI (kg/m2)		26 (3)		28 (5)		.205
Tumor Characteristics		N	%	N	%	p
Tumor Location	Mid 1/3	5	13%	3	25%	.388
	Distal 1/3	25	64%	8	67%
	GEJ	9	23%	1	8%
Histology	SCC	12	31%	4	33%	.849
	AC	26	67%	8	67%
	Other	1	3%	0	0%
cT	1	1	3%	0	0%	.732
	2	2	5%	1	8%
	3	35	90%	10	83%
	4	1	3%	1	8%
cN	0	7	18%	1	8%	.602
	1	21	54%	9	75%
	2	10	26%	2	17%
	3	1	3%	0	0%
Tumor Characteristics		N	%	N	%
Surgery Type	Open	18	46%	7	58%	.460
	MIE	21	54%	5	42%
		Mean (SD)		Mean (SD)
PTV (cc)		683 (258)		648 (239)		.684

cT and cN as staged according to TNM8; PTV: planning target volume for irradiation expressed in cc.

SCC: squamous cell carcinoma; AC: adenocarcinoma.

p-value for significance <0.05.

Table 2. Comparison of dose-volume parameters of anatomical and functional lung volumes Expressed in cc between patients with and without pulmonary complications.

	Postoperative pulmonary complications
	No (n = 39)		Yes (n = 12)
	Mean	SD	Mean	SD	p-value
ALV Mean Dose (Gy)	10.0	2.9	10.4	3.2	.335
FLV Mean Dose (Gy)	11.2	3.1	10.9	3.0	.404
ALV (cc)	3601	635	3141	858	.025
FLV (cc)	661	340	862	428	.125
ALV40Gy (cc)	45	26	57	48	.594
FLV40Gy (cc)	11	7	16	16	.484
ALV30Gy (cc)	159	102	153	154	.464
FLV30Gy (cc)	11	7	16	16	.484
ALV20Gy (cc)	580	256	593	316	.444
FLV20Gy (cc)	118	63	166	106	.030
ALV10Gy (cc)	1352	534	1274	627	.336
FLV10Gy (cc)	264	139	360	216	.038
ALV5Gy (cc)	2057	809	1851	915	.229
FLV5Gy (cc)	404	229	514	274	.149

ALV: anatomical lung volume; FLV: functional lung volume; SD: standard deviation; cc quantifies the absolute volume that is exposed to x Gy.

p-value for significance <0.05.

Table 3. Comparison of pulmonary function tests between patients with and without pulmonary complications.

	Postoperative pulmonary complications
	No (n = 39)			Yes (n = 12)
	Mean	SD	Missing	Mean	SD	Missing	p-value
TLC (% pred)	109.6	12.8	11	93.1	17.3	2	0.001
FEV1 (% pred) baseline	101.8	20.0	0	89.8	17.5	0	0.033
FEV1 (% pred) post	99.9	20.8	0	90.6	21.0	1	0.101
ΔFEV1 (% pred)	−1.9	8.3	0	.5	8.9	1	0.206
DLCO (% pred) baseline	87.4	18.0	6	82.3	9.3	0	0.180
DLCO (% pred) post	69.4	13.2	15	65.1	18.5	4	0.238
ΔDLCO (% pred)	−17.7	12.9	19	−15.3	13.0	4	0.327
Tiff (% pred) baseline	93.4	9.1	3	92.9	9.4	1	0.725
Tiff (% pred) post	91.6	7.5	3	91.6	12.1	1	0.489
ΔTiff (% pred)	−1.7	5.4	4	−1.3	4.1	1	0.403

FEV1: forced expiratory volume in 1 s; TLC: total lung capacity; DLCO: diffusing capacity for carbon monoxide; Tiff: tiffeneau index as calculated by FEV1 divided by vital capacity. Δ quantifies the differences before versus after neoadjuvant chemoradiotherapy.

% pred quantifies the pulmonary function test in comparison with predicted normal values, based on a patient’s sex, height, age and race.

SD: standard deviation; p-value for significance <0.05.

Table 4. Comparison of pulmonary function test results before versus after neoadjuvant Chemoradiotherapy.

	Mean baseline	SD	Mean post-nCRT	SD	p-value
FEV1 (% pred)	99.2	20.0	97.8	21.0	0.122
DLCO (% pred)	85.0	17.2	68.0	15.0	<0.001
Tiff (% pred)	93.1	9.0	91.5	8.7	0.019

FEV1: forced expiratory volume in 1 s; DLCO: diffusing capacity for carbon monoxide; Tiff: tiffeneau index as calculated by FEV1 divided by vital capacity.

% pred quantifies the pulmonary function test in comparison with predicted normal values, based on a patient’s sex, height, age and race.

SD: standard deviation; p-value for significance <0.05.

Data availability statement

Raw data were generated at UZ Leuven. Derived data supporting the findings of this study are available from the corresponding author on request.