Dose distribution and tumor control probability in out-of-field lymph node stations in intensity modulated radiotherapy (IMRT) vs 3D-conformal radiotherapy (3D-CRT) of non-small-cell lung cancer: an in silico analysis

Table 4 IMRT vs. 3D-CRT: PTV based dosimetric parameters stratified by treatment volume concept for all 41 patients. IMRT dose was also normalized to a prescription dose equaling 3D-CRT dose in each patient, indicated as IMRT_norm

	IMRT	IMRT_norm	3D-CRT	p
Mean dose (Gy)
LN_all	36.7 ± 11.0	32.5 ± 7.5	37.1 ± 9.9	<0.0001*
LN_adj	46.6 ± 9.7	37.9 ± 9.3	47.6 ± 8.6	<0.0001*
EUD (Gy)
LN_all	32.2 ± 8.7	30.5 ± 8.3	33.5 ± 9.7	<0.01*/<0.00001
LN_adj	42.7 ± 9.3	40.4 ± 8.7	44.2 ± 9.0	<0.001*/<0.00001
TCP (%)
LN_all	13.8 ± 11.2	12.6 ± 9.9	14.8 ± 13.2	<0.01*
LN_adj	25.7 ± 21.4	23.6 ± 19.4	27.3 ± 21.7	<0.001*

Data are presented as means ± standard deviation
IMRT intensity modulated radiotherapy, 3D-CRT 3D-conformal radiotherapy, PTV planning target volume, LN _all all hilar and mediastinal lymph node stations without evidence of disease as staged with FDG-PET, LN _adj hilar and mediastinal lymph node stations without evidence of disease as staged with FDG-PET, but directly adjacent to involved lymph node stations, TCP tumor control probability, ns not significant
*Test for statistical significance performed for IMRT_norm vs. 3D-CRT (values only indicated if significant)
**Test for statistical significance performed for IMRT vs. 3D-CRT (values only indicated if significant)

ISSN: 1748-717X