Stratification of outcomes for mucinous appendiceal adenocarcinoma with peritoneal metastasis by histological grade

Table 1 Baseline clinical and pathological characteristics of the 265 patients with mucinous appendiceal adenocarcinoma treated with cytoreduction and hyperthermic intraperitoneal chemotherapy stratified by histological grade n (%)

Characteristics of the entire cohort (n = 265)	Well-differentiated (n = 201)	Moderately-differentiated (n = 45)	Poorly-differentiated (n = 19)	Total	P value
Age	53.1 (45-59)	54.9 (46-59)	49.6 (45-60)	53.4 (45-59)	P = 0.963
Sex					P = 0.622
Male	78 (39)	21 (47)	8 (42)	107 (40.4)
Female	123 (61)	24 (53)	11 (58)	158 (59.6)
Signet ring cell					P < 0.00112
> 50%	0	3 (7)	11 (58)	14 (5.3)
1%-50%	6 (3)	4 (9)	0	10 (3.8)
None	195 (97)	38 (84)	8 (42)	241 (90.9)
LVI					P < 0.00112
Yes	3 (1)	8 (18)	9 (47)	20 (7.5)
No	198 (98)	35 (78)	3 (16)	241 (90.9)
LN involvement					P < 0.00112
Yes	11 (5)	4 (9)	8 (42)	23 (8.7)
No	160 (80)	38 (84)	4 (21)	208 (78.5)
Neoadjuvant chemo					P < 0.00112
Yes	29 (14)	21 (47)	15 (79)	65 (24.5)
No	172 (86)	24 (53)	4 (21)	200 (75.5)
Adjuvant chemo					P < 0.00112
Yes	12 (6)	3 (7)	8 (42)	23 (8.7)
No	189 (94)	42 (93)	11 (58)	242 (91.3)
PSS					P = 0.0522
0	77 (38)	20 (44)	7 (37)	104 (39.2)
1	59 (29)	13 (29)	3 (16)	75 (28.3)
2	44 (22)	6 (13)	9 (47)	59 (22.3)
3	21 (10)	6 (13)	0	27 (10.2)
Albumin	4.2 (4.0-4.4)	4.3 (4.1-4.5)	4.2 (4.0-4.9)	4.2 (4.1-4.5)	P = 0.773
CEA	2.8 (1.3-10.7)	4.5 (2.4-15.7)	2.2 (1.4-4.9)	3.4 (1.5-10.5)	P = 0.923
PCI	17.5 (11-26)	14 (8-24)	15.5 (12-25)	16.5 (10-25)	P = 0.453
Completeness of cytoreduction					P = 0.322
CC 0-1	176 (88)	40 (89)	15 (79)	231 (87.2)
CC 2-3	19 (9)	5 (11)	4 (21)	28 (10.6)
Unknown				6 (2.3)
OR time	9.2 (7.7-11.4)	8.7 (6.9-10.0)	7.9 (6.9-10.5)	8.9 (7.5-11.1)	P = 0.823
Blood loss	600 (350-997)	375 (250-588)	350 (250-550)	500 (300-900)	P = 0.00713
LOS	19 (13-27)	13 (10-22)	16 (10-23)	17 (12-26)	P = 0.00813
30 d morbidity any grade	108 (54)	28 (68)	11 (58)	149 (55)	P = 0.492
90 d grade III/IV	35 (17)	14 (31)	2 (10)	51 (19.2)	P = 0.352
90 d mortality	2 (1)	0	0	2 (0.8)	P = 0.732

Descriptive statistics are reported as median and interquartile range or number and frequency.

¹Significant P-values;

²χ² test;

³Kruskal-Wallis test. LVI: Lymphovascular invasion; PSS: Previous surgical score; CEA: Carcinoembryonic antigen; PCI: Peritoneal carcinomatosis index; LOS: Length of stay.

Table 2 Univariate and Multivariate models using Cox regression analysis for disease-free and overall survival

Disease-free survival				Overall survival
Univariate	P value	Multivariate (HR, 95%CI)	P value	Univariate	P value	Multivariate (HR, 95%CI)	P value
Age	0.45			Age	0.35
Sex	0.051		0.59	Sex	< 0.0011		0.13
Albumin	0.27			Albumin	0.28
ECOG status	0.38			ECOG status	0.0061		0.15
Pre-op CEA	0.39			Pre-op CEA	0.07		0.51
Grade	< 0.0011	1.8 (1.2-2.8)	0.0081	Grade	< 0.0011	2.80 (1.26-6.21)	0.011
Signet ring cell	< 0.0011		0.828	Signet ring cell	< 0.0011		0.22
Lympho-vascular invasion	< 0.0011		0.15	Lympho-vascular invasion	< 0.0011		0.82
Lymph node metastasis	< 0.0011	0.42 (0.20-0.88)	0.021	Lymph node metastasis	< 0.0011		0.47
PSS	0.09	1.3 (1.1-1.6)	0.031	PSS	0.14
PCI	0.031	1.05 (1.02-1.08)	0.0021	PCI	< 0.001	1.10 (1.03-1.16)	0.0021
				CC0 resection	< 0.0011	0.32 (0.11-0.92)	0.03

¹Significant variables. ECOG: Eastern Cooperative Oncology Group; CEA: Carcinoembryonic antigen; PSS: Previous surgical score; PCI: Peritoneal carcinomatosis index.

Table 3 Illustrates the incidence of lymph node metastasis as stratified by histological grade, and the presence or absence of signet ring cells

	Incidence of lymph node metastasis
Histological grade		P < 0.001
Well-differentiated	5.50%
Moderately-differentiated	10.80%
Poorly-differentiated	42.10%
Signet ring cell		P = 0.08
Absent	7.50%
Present	20.80%
Moderately-differentiated and LVI-	6%	P = 0.008
Moderately-differentiated and LVI+	40%

The incidences of lymph node metastasis for the moderately-differentiated tumors are further stratified by lymphovascular invasion (LVI).