Excluding external iliac node irradiation during neoadjuvant radiotherapy decreases lower intestinal toxicity without compromising efficacy in T4b rectal cancer patients with tumours involving the anterior structures

Table 1 Baseline clinical characteristics and treatment details of the rectal cancer patients

	EIN (n = 29)	NEIN (n = 103)	P value
Age (years) median (range)	56 (28–74)	55 (24–81)	0.963
Gender
Male	11 (37.9%)	39 (37.9%)
Female	18 (62.1%)	64 (62.1%)	1.000
Clinical stage
II	2 (6.9%)	5 (4.9%)
III	27 (93.1%)	98 (95.1%)	0.648
cN stage
cN0	2 (6.9%)	5 (4.9%)
cN1	2 (6.9%)	12 (11.7%)
cN2	7 (24.1%)	43 (41.7%)
cN1–2^a	18 (62.1%)	43 (41.7%)	0.192
Distance from anal verge
< 5 cm	11 (37.9%)	43 (41.7%)
5–10 cm	15 (51.7%)	51 (49.5%)
> 10 cm	3 (10.3%)	9 (8.7%)	0.862
Pretreatment CEA
≤ 5 ng/ml	15 (51.7%)	48 (46.6%)
> 5 ng/ml	14 (48.3%)	55 (53.4%)	0.626
Type of radiation
3D-CRT	5 (17.2%)	16 (15.5%)
IMRT	24 (82.8%)	87 (84.5%)	0.780
Concurrent chemotherapy
No	0 (0.0%)	4 (3.9%)
XELOX	6 (20.7%)	36 (35.0%)
Capecitabine	22 (75.9%)	60 (58.3%)
Other	1 (3.4%)	3 (2.9%)	0.293
Interval from RT to surgery (days), median (range)	63 (43–96)	68 (24–211)	0.106
Type of surgery
Abdominoperineal resection	3 (10.3%)	11 (10.7%)
Anterior resection	17 (58.6%)	68 (66.0%)
Multivisceral resection	8 (27.6%)	21 (20.4%)
Other	1 (3.4%)	3 (2.9%)	0.811
Pathological complete response
Yes	2 (6.9%)	15 (14.6%)
No	27 (93.1%)	88 (85.4%)	0.361

EIN, group with external iliac nodes radiation; NEIN, group without external iliac nodes radiation; 3D-CRT, 3-dimensional conformal radiotherapy; IMRT, intensity modulated radiotherapy; RT, radiotherapy
^aPatients had lymph node metastasis but N stage could not be determined