Evaluating the predictive value of endoscopic findings for residual colorectal cancer following neoadjuvant combination immunotherapy

Table 1 Patient characteristics, n (%)

Characteristics	pMMR (n = 57)	dMMR (n = 17)
Age (years)	59 (51-66.5)	43 (37-63.5)
Sex (male)	37 (64.9)	10 (58.8)
BMI (kg/m2)	23.4 (21.0-25.7)	23.5 (21.8-28.5)
Primary tumor location
Ascending colon	5 (8.8)	7 (41.2)
Sigmoid colon	10 (17.5)	3 (17.6)
Rectum	42 (73.7)	7 (41.2)
Clinical TNM stage
II	10 (17.5)	1 (5.9)
III	36 (63.2)	14 (82.4)
IV	11 (19.3)	2 (11.8)
Clinical T-stage
T3	35 (61.4)	9 (52.9)
T4	22 (38.6)	8 (47.1)
Clinical N-stage
Negative	12 (21.1)	1 (5.9)
Positive	45 (78.9)	16 (94.1)
CEA elevation (≥ 5 μg/L)	26 (45.6)	3 (17.6)
Histological appearance
Well differentiated	2 (3.5)	0
Moderately differentiated	9 (15.8)	2 (11.8)
Poorly differentiated	46 (80.7)	15 (88.2)
Neoadjuvant immunotherapy
PD-1 inhibitor	39 (68.4)	12 (70.6)
PD-L1 inhibitor	6 (10.5)	1 (5.9)
PD-1 + CTLA-4 inhibitors	12 (21.1)	4 (23.5)
Previous treatment
NAC	39 (68.4)	9 (52.9)
Target therapy	15 (26.3)	2 (11.8)
NRT	26 (65.6)	2 (11.8)
Days from diagnosis to initiation of any therapy	28 (17-41.5)	31 (14-52)
Days from initiation of any therapy to completion of all therapy	97 (76-122)	90 (42.5-150)
Days from completion of all therapy to surgery	50 (31.5-63)	42 (35-68)
pCR rate	17 (29.8)	14 (82.4)
TRG
1	7 (12.3)	1 (5.9)
2	23 (40.4)	0
3	10 (17.5)	3 (17.6)
4	17 (29.8)	13 (76.5)
Pathological T stage
ypT0	18 (31.6)	13 (76.5)
ypT1	4 (7.0)	1 (5.9)
ypT2	11(19.3)	2(11.8)
ypT3	16 (28.3)	0
ypT4	8 (14.0)	1 (5.9)
Pathological N stage
ypN0	42 (73.7)	16 (94.1)
ypN1	9 (15.8)	1 (5.9)
ypN2	6 (10.5)	0
Vascular invasion	6 (10.5)	1 (5.9)
Perineural invasion	13 (22.8)	1 (5.9)

pMMR: Proficient mismatch repair; dMMR: Deficient mismatch repair; BMI: Body mass index; TNM: Tumor node metastasis; CEA: Carcinoembryonic antigen; PD-1: Programmed cell death protein-1; PD-L1: Programmed cell death ligand-1; CTLA-4: Cytotoxic T-lymphocyte-associated protein 4; NAC: Neoadjuvant chemotherapy; NRT: Neoadjuvant radiotherapy; pCR: Pathological complete response; TRG: Tumor regression grade.

Table 2 Presence of endoscopic findings before surgery in 57 mismatch repair proficient patients, n (%)

	Total (n = 57)	Residual disease (n = 40)	Complete response (n = 17)	P value
CR	12 (21.1)	1 (2.5)	11 (64.7)	< 0.01
NCR	17 (29.8)	12 (30.0)	5 (29.4)	0.96
PR	23 (40.4)	22 (55.0)	1 (5.9)	< 0.01
SD	5 (8.8)	5 (12.5)	0 (0)	0.31

CR: Complete response; NCR: Near-complete response; PR: Partial response; SD: Stable disease.

Table 3 Presence of endoscopic findings before surgery in 17 mismatch repair deficient patients, n (%)

	Total (n = 17)	Residual disease (n = 3)	Complete response (n = 14)	P value
CR	2 (11.8)	0 (0)	2 (14.3)	0.67
NCR	4 (23.5)	1 (33.3)	3 (21.4)	0.58
PR	11 (64.7)	2 (66.7)	9 (64.3)	0.73

CR: Complete response; NCR: Near-complete response; PR: Partial response.

Table 4 Diagnostic of complete response in endoscopic compared to pathological complete response

	pMMR (n = 57)	dMMR (n = 17)
Sensitivity	64.7	100
Specificity	97.5	0
PPV	91.7	82.4
NPV	86.7	0
Accuracy	87.7	82.4

pMMR: Proficient mismatch repair; dMMR: Deficient mismatch repair; PPV: Positive predictive value; NPV: Negative predictive value.

Table 5 Endoscopic features of 74 patients before surgery, n (%)

	pMMR, present	pMMR, absent	dMMR, present	dMMR, absent
Ulceration	38 (66.7)	19 (33.3)	13 (76.4)	4 (23.6)
Easy bleeding	42 (73.7)	15 (26.3)	13 (76.5)	4 (23.5)
Focal retraction	55 (96.5)	2 (3.5)	17 (100)	0 (0)
Residual mass	49 (86.0)	8 (14.0)	15 (88.2)	2 (11.8)
Eccentric stenosis	22 (38.6)	35 (61.4)	11 (64.7)	6 (35.3)

pMMR: Proficient mismatch repair; dMMR: Deficient mismatch repair.