Real-time in vivo distal margin selection using confocal laser endomicroscopy in transanal total mesorectal excision for rectal cancer

Table 1 Patient demographics and tumor characteristics

Variable	n = 43
Age: Median (IQR), yr	57 (47-65)
Sex: Male/female, n	29/14
BMI: Median (IQR), kg/m2	22.40 (19.50-23.95)
ASA class, n (%)
1	8 (18.6)
2	30 (69.8)
3	5 (11.6)
4	0
Tumor size: Median (IQR), cm	2.5 (2.0-3.8)
Tumor height1: Median (IQR), cm	4.0 (3.6-4.6)
Histological subtype, n (%)
Adenocarcinoma	39 (90.7)
Mucinous adenocarcinoma/signet ring cell carcinoma	4 (9.3)
Differentiation grade, n (%)
Well	7 (16.3)
Moderate	32 (74.4)
Poor	4 (9.3)
Neoadjuvant chemoradiotherapy, n (%)	21 (48.8)
TRG2, n (%)
Grade 0	3 (7.0)
Grade 1	10 (23.3)
Grade 2	7 (14.0)
Grade 3	1 (2.3)
T stage, n (%)
T0	5 (11.6)
T1	4 (9.3)
T2	17 (39.5)
T3	13 (30.2)
T4	4 (9.3)
N stage, n (%)
N0	30 (69.8)
N1	10 (23.3)
N2	3 (7.0)
M stage, n (%)
M0	43 (100)
M1	0

¹Height of the distal edge of the tumor from the anal verge.

²Tumor regression grade.

BMI: Body mass index; ASA: American Society of Anesthesiologists; TRG: Tumor Regression Grade; IQR: Interquartile range.

Table 2 Probe-based confocal laser endomicroscopy diagnostic accuracy considering pathology as the standard reference

	Observer A (real-time interpretation)		Observer B (blinded interpretation)
	%	95%CI	%	95%CI
Sensitivity	90.00	76.34-97.21	87.50	73.20-95.81
Specificity	86.96	73.74-95.06	84.78	71.13-93.66
Accuracy	88.37	79.65-94.28	86.05	76.89-92.58
PPV	85.71	71.46-94.57	83.33	68.64-93.03
NPV	90.91	78.33-97.47	88.64	75.44-96.21
Interobserver agreement	κ = 0.767, standard error = 0.069

CI: Confidence interval; PPV: Positive predictive value; NPV: Negative predictive value.

Table 3 Comparison of real-time probe-based confocal laser endomicroscopy diagnostic accuracy between the neoadjuvant group and the nonneoadjuvant group

	Neoadjuvant group (n = 42)		Nonneoadjuvant group (n = 44)		P value
	%	95%CI	%	95%CI
Sensitivity	83.33	58.58-96.42	95.45	77.16-99.88	0.458
Specificity	77.27	54.63-92.18	95.83	78.88-99.89	0.153
Accuracy	80.00	64.35-90.95	95.65	85.16-99.47	0.055
PPV	75.00	50.90-91.34	95.45	77.16-99.88	0.147
NPV	85.00	62.11-96.79	95.83	78.88-99.89	0.473

CI: Confidence interval; PPV: Positive predictive value; NPV: Negative predictive value.

Table 4 Surgical and functional outcomes

Variable
Operative duration: Median (IQR), min	240 (202-265)
pCLE examination duration: Median (IQR), min	17 (15-18)
Estimated blood loss: Median (IQR), mL	27 (20-50)
DRM distance: Median (IQR), mm	7.0 (5.0-10.0)
Anastomotic leakage, n (%)	2 (4.7)
Positive DRM, n (%)	0 (0)
Wexner score1, median (IQR)	5 (3-6)
Anastomotic stenosis, n (%)	1 (2.3)
Recurrence, n (%)	1 (2.3)
Metastasis, n (%)	2 (4.7)

¹An incontinence score designed by Wexner, determined at 6 mo after stoma closure.

pCLE: Probe-based confocal laser endomicroscopy; DRM: Distal resection margin; IQR: Interquartile range.