Adjuvant therapy sparing in rectal cancer achieving complete response after chemoradiation

Table 1 Descriptive baseline statistics by type of response achieved

Variable	Complete1	Intermediate2	Poor3	P value
	(n = 26)	(n = 47)	(n = 97)
Age, yr	65.5 (39.9-84.9)	65.7 (42.9-84.0)	65.5 (41.3-83.5)	0.8407
Female	11 (42)	14 (30)	29 (30)	0.4551
CEA4				0.0122
< 3.6 μg/L	21 (81)	26 (55)	47 (49)
3.6-20.9 μg/L	5 (19)	20 (43)	41 (42)
> 20.9 μg/L	0	0	9 (9)
Presurgical hemoglobin, g/dL	13.1 (9.2-16.0)	14.0 (7.9-18.2)	13.4 (7.6-18.4)	0.0580
Clinical stage				0.1325
cT2N0	0	25 (4)	0 (0)
cT2N1	0	3 (6)	3 (3)
cT3N0	11 (42)	21 (45)	38 (39)
cT3N1	14 (54)	14 (30)	38 (39)
cT4N0	1 (4)	0 (0)	2 (2)
cT4N1	0	0	3 (3)
Severe stenosis precluding staging	0	7 (15)	13 (13)
Distance from tumor to anal margin, cm	7.0 (2.0-12.0)	5.0 (1.0-15.0)	8.0 (1.0-15.0)	0.0697
Previous abdominal surgery	14 (54)	16 (34)	39 (40)	0.2546
Type of surgery				0.5368
APR or miles intervention	4 (15)	8 (17)	23 (24)
Low-anterior resection	21 (81)	33 (70)	65 (67)
Other	1 (4)	6 (13)	9 (9)
Laparoscopic vs open surgery				0.1748
Fully laparoscopic	25 (96)	42 (89)	77 (79)
Intraoperative conversion to open	1 (4)	4 (9)	12 (12)
Open from the beginning	0	1 (2)	8 (8)
Hospital stay, d	5.0 (3.0-16.0)	6.5 (4-55)	7 (2-145)	0.0164
Number of lymph nodes resected	11 (1-27)	10 (1-33)	12 (1-29)	0.3768
Patients with ≥ 12 lymph nodes resected	12 (46)	20 (43)	49 (51)	0.6600
Involvement of radial margin				< 0.0001
No	26 (100)	44 (94)	62 (64)
Yes	0	0	15 (16)
Not assessed	0	3 (6)	20 (21)

Values are presented as n (%) or median (range), unless otherwise indicated.

¹ypT0N0;

²ypT1-2N0;

³ypT3-4N1-2;

⁴This variable has one missing value;

⁵Although cT2N0 staging was considered an exclusion criterion, these tumors were located in the low rectum and we considered the risk of local relapse without neoadjuvant chemoradiotherapy too high. APR: Abdominoperineal resection; CEA: Carcinoembryonic antigen.

Table 2 Multivariate analysis of disease-free survival

Variable	Main cohort		External reference cohort
	HR (95%CI)	P value	HR (95%CI)	P value
Type of response after CRT
ypT0N0	0.07 (0.01-0.54)	0.0100	0.51 (0.15-1.7)	0.2700
ypT1-2N0	0.16 (0.06-0.46)	0.0007	0.41 (0.18-0.94)	0.0360
ypT3-4/N1-2	Reference		Reference
CEA	1.02 (1.01-1.03)	0.0010	1.02 (1.01-1.03)	0.0072
Pre-surgery clinical stage
T2-3N0	Reference		Reference
T4 and/or N1	1.19 (0.82-1.73)	0.3500	1.66 (0.85-3.26)	0.1400
Admission stay after surgery1, d	1.02 (1.01-1.02)	0.0020

¹This variable was not available in the external reference cohort. CEA: Carcinoembryonic antigen; CRT: Chemoradiotherapy.

Table 3 Multivariate analysis of overall survival

Variable	Main cohort		External reference cohort
	HR (95%CI)	P value	HR (95%CI)	P value
Chemotherapy1	1.09 (0.55-2.16)	0.810
Type of response after CRT
ypT0N0	NE		0.61 (0.19-2.02)	0.420
ypT1-2N0	0.30 (0.11-0.78)	0.014	0.32 (0.13-0.83)	0.019
ypT3-4/N1-2	Reference		Reference
CEA	1.00 (0.97-1.03)	0.780
Presurgical clinical stage
T2-3N0			Reference
T4 and/or N1			1.89 (0.95-3.76)	0.069

¹This factor was not evaluated in the external reference cohort because all patients were scheduled to receive chemotherapy. CEA: Carcinoembryonic antigen; CRT: Chemoradiotherapy; NE: Not estimable (no deaths).