Microscopic spread of low rectal cancer in regions of mesorectum: Pathologic assessment with whole-mount sections

Table 1 Clinicopathologic characteristics of the 62 patients

Parameters	Results
Age (yr, range, mean)	20-78, 58
Sex (No. of patients)
Male	30
Female	32
Dukes stage (No. of patients)
A	2
B	10
C	42
D	8
Differentiation grade (No. of patients)
High	4
Medium	34
Low	24
Distance of the primary tumor from anal verge (No. of patients)
≤ 5 cm	32
> 5 cm	30
Diameter of the primary tumor (No. of patients)
< 5 cm	24
≥ 5 cm	38

Table 2 Mesorectal regions with involvement of discrete tumor nodules (%)

	Involved mesorectal regions
	MR	ORM	MRM	IRM	DMR	CRM
Tumor nodules	58.1 (36/62)	45.2 (28/62)	35.5 (22/62)	41.9 (26/62)	6.5 (4/62)	6.5 (4/62)
Microscopic tumor nodules	38.7 (24/62)	25.8 (16/62)	25.8 (16/62)	29.0 (18/62)	6.5 (4/62)	6.5 (4/62)

MR: mesorectum; ORM: outer region of mesorectum; MRM: middle region of mesorectum; IRM: inner region of mesorectum; DMR: distal mesorectum; CRM: circumferential resection margin.

Table 3 Mesorectal regional discrete microscopic tumor nod-ules involving lymph nodes or lymphatic vessels

	Involvement of MR	Involvement of ORM
L type (No. of patients)	16	14
NL type (No. of patients)	18	13

MR: mesorectum; ORM: outer region of mesorectum; L type: involving lymph nodes or lymphatic vessel; NL type: with-out involving lymph nodes or lymphatic vessels.

Table 4 Correlation between mesorectal microscopic spread and primary tumors

Primary tumor	Spread in MR (No. of patients)	Spread in ORM (No. of patients)
Diameter: < 5 cm/ ≥ 5 cm	10/14	8/8
Differentiation grade: high/medium/low	0/10/14	0/8/8
Dukes stage: A/B/C/D	0/2/20/2	0/2/12/2
From anal verge: ≤ 5 cm/ > 5 cm	12/12	8/8

MR: mesorectum; ORM: outer region of mesorectum.