Right- and left-sided stage III colon cancers present different prognostic outcomes of oxaliplatin-based adjuvant chemotherapy after curative resection

Figures & data

Table 1 Clinicopathological characteristics of patients with stage III colon cancer

Variables	Overall cases (%)	Right-sided colon (n, %)	Left-sided colon (n, %)	P-value
Total	274	110 (40.1)	164 (59.9)
Age (years)				0.974
≤60	189 (69.0)	76 (69.1)	113 (68.9)
>60	85 (31.0)	34 (20.9)	51 (31.1)
Gender				0.401
Male	156 (56.9)	66 (60.0)	90 (54.9)
Female	118 (43.1)	44 (40.0)	74 (45.1)
Baseline BMI (kg/m^2)				0.992
<18.5	28 (10.2)	11 (10.0)	17 (10.4)
18.5–25.0	187 (68.2)	75 (68.2)	111 (68.1)
>25	59 (21.5)	24 (21.8)	35 (21.5)
Baseline hemoglobin (g/L)				0.002
<90	42 (15.3)	26 (23.6)	16 (9.8)
≥90	232 (84.7)	84 (76.4)	148 (90.2)
Tumor size (cm)
≤4	140 (51.1)	43 (39.1)	97 (59.1)	0.001
>4	134 (48.9)	67 (60.9)	67 (40.9)
Differentiation
Well/moderate	207 (75.5)	77 (70.0)	130 (79.3)	0.080
Poor/undifferentiated	67 (24.5)	33 (30.0)	34 (20.7)
T stage
T1–T2	12 (4.4)	2 (1.8)	10 (6.1)	0.138
T3	121 (44.2)	54 (49.1)	67 (40.9)
T4	141 (51.5)	54 (49.1)	87 (53.0)
Number of resected lymph nodes				<0.001
<12	73 (26.6)	15 (13.6)	58 (35.4)
≥12	201 (73.4)	95 (86.4)	106 (64.6)
N stage
N1	189 (69.0)	77 (70.0)	112 (68.3)	0.765
N2	85 (31.0)	33 (30.0)	52 (31.7)
TNM stage
IIIA	10 (3.6)	2 (1.8)	8 (4.9)	0.409
IIIB	202 (73.7)	82 (74.5)	120 (73.2)
IIIC	62 (22.6)	26 (23.6)	36 (22.0)
Preoperative serum CEA (ng/mL)				0.771
≤5	159 (58.0)	65 (59.1)	94 (57.3)
>5	115 (42.0)	45 (40.9)	70 (42.7)
Cycles of adjuvant XELOX chemotherapy*				0.074
<6	54 (19.5)	27 (24.5)	26 (15.9)
6–8	223 (80.5)	83 (75.5)	138 (84.1)

Notes:

* XELOX adjuvant chemotherapy was administered as follows: oxaliplatin at a dose of 130 mg/m² was administered intravenously on day 1, and capecitabine was administered orally at a dosage of 1000 mg/m² twice daily on days 1–14 for a 3-week cycle.

Abbreviations: BMI, body mass index; TNM, tumor-node-metastasis; CEA, carcinoembryonic antigen.

Figure 1 Median cycle of XELOX adjuvant chemotherapy received by patients for each tumor location.

Notes: *XELOX adjuvant chemotherapy was administered as follows: oxaliplatin at a dose of 130 mg/m² was administered intravenously on day 1, and capecitabine was administered orally at a dosage of 1000 mg/m² twice daily on days 1–14 for a 3-week cycle.

Table 2 Treatment-related toxicities during adjuvant chemotherapy in patients with stage III colon cancer after curative resection

Toxicities	Right-sided colon cancer (n = 110, %)	Left-sided colon cancer (n = 164, %)	P-value
Leucopenia
Total	63 (57.3)	93 (56.7)	0.926
Grade 1–2	54 (49.1)	81 (49.4)	0.961
Grade 3–4	9 (8.2)	12 (7.3)	0.792
Thrombocytopenia
Total	44 (40.0)	68 (41.5)	0.809
Grade 1–2	32 (29.1)	54 (32.9)	0.502
Grade 3–4	12 (10.9)	14 (8.5)	0.511
Nausea/vomiting
Total	22 (20.0)	36 (22.0)	0.698
Grade 1	11 (10.0)	21 (12.8)	0.734
Grade 2–3	11 (10.0)	15 (9.1)	0.813
Diarrhea
Total	18 (16.4)	18 (11.0)	0.196
Grade 1	9 (8.2)	12 (7.3)	0.792
Grade 2–3	9 (8.2)	6 (3.7)	0.107
Hand-foot syndrome
Total	57 (51.8)	68 (41.5)	0.092
Grade 1	47 (42.7)	53 (32.3)	0.079
Grade 2–3	10 (9.1)	15 (9.1)	0.988
Hepatic disorder
Total	39 (35.5)	50 (30.5)	0.389
Grade 1	29 (26.4)	35 (21.3)	0.335
Grade 2–3	10 (9.1)	15 (9.1)	0.988
Neurotoxicity
Total	78 (70.9)	105 (64.0)	0.236
Grade 1	59 (53.6)	67 (40.9)	0.037
Grade 2–3	20 (18.2)	38 (23.2)	0.322

Table 3 Postoperative metastatic patterns of patients with stage III colon cancer after curative treatment

Metastatic parameters	Right-sided colon (n = 110, %)	Left-sided colon (n = 164, %)	P-value
Postoperative metastasis			0.396
Yes	24 (21.8)	29 (17.7)
No	86 (78.2)	135 (82.3)
Liver metastasis			0.260
Yes	6 (5.5)	15 (9.1)
No	104 (94.5)	149 (90.9)
Lung metastasis			0.372
Yes	5 (2.7)	9 (5.5)
No	107 (97.3)	155 (94.5)
Abdominopelvic metastasis			0.003
Yes	12 (10.9)	4 (2.4)
No	98 (89.1)	160 (97.6)

Table 4 Univariate and multivariate analyses of prognostic factors for overall survival in patients with stage III colon cancer who received curative treatment

Variables	Univariate		Multivariate
	HR (95% CI)	P-value	HR (95% CI)	P-value
Age, years (>60 vs. ≤60)	1.390 (0.661–2.925)	0.385
Gender (male vs. female)	1.902 (0.871–4.154)	0.107
Baseline BMI, kg/m^2 (<18.5 vs. ≥18.5)	1.892 (0.724–4.944)	0.193
Baseline hemoglobin, g/L (<90 vs. ≥90)	0.818 (0.285–2.346)	0.709
Tumor size, cm (>4 vs. ≤4)	1.046 (0.511–2.140)	0.902
Differentiation (poor vs. well/moderate)	1.181 (0.525–2.656)	0.687
T stage (T4 vs. T1–3)	1.709 (0.797–3.668)	0.169
Number of resected lymph nodes (<12 vs. ≥12)	1.080 (0.480–2.429)	0.853
N stage (N2 vs. N1)	1.487 (0.716–3.089)	0.287
Preoperative serum CEA, ng/mL (>5 vs. ≤5)	0.987 (0.479–2.034)	0.972
Adjuvant chemotherapy, cycle (6–8 vs. <6)	0.308 (0.148–0.640)	0.002	0.329 (0.158–0.685)	0.003
Tumor location (right-sided colon vs. left-sided colon)	2.243 (1.089–4.619)	0.020	2.213 (1.063–4.606)	0.002

Abbreviations: BMI, body mass index; HR, hazard ratio; CEA, carcinoembryonic antigen.

Figure 2 Kaplan–Meier curves of patients with stage III colon cancer grouped by right- and left-sided colon and stratified by stage.

Notes: (A) Disease-free survival (DFS) of all patients. (B) Overall survival (OS) of all patients. (C) DFS of patients with stage IIIA–B colon cancer. (D) OS of patients with stage IIIA–B colon cancer. (E) DFS of patients with stage IIIC colon cancer. (F) OS of patients with stage IIIC colon cancer.

Figure 3 Kaplan–Meier curves of patients with stage III colon cancer in right- and left-sided colon stratified by cycles of XELOX* adjuvant chemotherapy.

Notes: (A) Disease-free survival (DFS) in left-sided colon cancer. (B) Overall survival (OS) in left-sided colon cancer. (C) DFS in right-sided colon cancer. (D) OS in right-sided colon cancer. *XELOX adjuvant chemotherapy was administered as follows: oxaliplatin at a dose of 130 mg/m² was administered intravenously on day 1, and capecitabine was administered orally at a dosage of 1000 mg/m² twice daily on days 1–14 for a 3-week cycle.