Fat clearance and conventional fixation identified ypN0 rectal cancers following intermediate neoadjuvant radiotherapy have similar long-term outcomes

Table 1 Patient characteristics, pre-staging methods, and pathological stages of conventional fixation group versus fat clearance group, n (%)

Characteristic	Conventionalfixation (n = 101)	Fat clearance (n = 124)	P value
Sex
Male	64 (63.4)	69 (55.6)	0.241
Female	37 (36.6)	55 (44.4)
Age (yr)
Median	62	58	0.496
Range	28-83	32-84
cT stage
T0-2	4 (4.0)	9 (7.3)	0.170
T3	93 (92.1)	114 (91.9)
T4a	4 (4.0)	1 (0.8)
cN stage
N0	26 (25.7)	30 (24.2)	0.789
N+	75 (74.3)	94 (75.8)
Distance from anal verge (cm)
Median	5	5	0.299
Range	2-10	1-9
Pre-treatment staging
MRI + ERUS	27 (26.7)	22 (17.7)	0.428
MRI	15 (14.9)	23 (18.5)
CT + ERUS	15 (14.9)	19 (15.3)
ERUS	30 (29.7)	35 (28.2)
CT	14 (13.9)	25 (20.2)
Interval from RT to surgery
Median	2	2	0.702
Range	1-8	1-6
Type of resection
Non-APR	68 (67.3)	90 (72.6)	0.391
APR	33 (32.7)	34 (27.4)
ypT stage
ypCR	7 (6.9)	14 (11.3)	0.550
T1	8 (7.9)	11 (8.9)
T2	37 (36.6)	51 (41.1)
T3	47 (46.5)	47 (37.9)
T4a	2 (2.0)	1 (0.8)
CRM status
Positive	6 (5.9)	8 (6.5)	0.875
Negative	95 (94.1)	116 (93.5)

MRI: Magnetic resonance imaging; ERUS: Endorectal ultrasound; CT: Computed tomography; RT: Radiotherapy; CRM: circumferential resection margin.

Table 2 Lymph nodes retrieval, local recurrence-free survival, and cancer-specific survival of conventional fixation group versus fat clearance group

Characteristic	Fat clearance	Conventionalfixation	P value
LNs retrieved [median (range)]
All T stages	19.5 (4-57)	12 (0-44)	0.000
ypT0-2	19 (5-57)	9 (0-30)	0.000
ypT3-4	21.5 (4-55)	13 (1-44)	0.000
Lymph nodes ≥ 12
All T stages	82.3%	50.5%	0.000
ypT0-2	81.6%	34.6%	0.000
ypT3-4	83.3%	67.3%	0.068
5 yr-LRFS rate	95.7%	94.6%	0.819
5 yr-CSS rate	92.0%	87.2%	0.482

LN: Lymph node; LRFS: Local recurrence-free survival; CSS: Cancer-specific survival.