Longitudinal changes in the gut microbiota of Vietnamese patients with colorectal cancer undergoing surgery and chemotherapy

Table 1 Clinical characteristics of patients with colorectal cancer, n (%)

Characteristic	Categories	Number of patients
Age at diagnosis (years): 64.3 ± 8 years	50-60	10 (32.3)
	60-70	10 (32.3)
	70-80	11 (35.5)
BMI	Normal weight	25 (80.6)
	Overweight	4 (12.9)
	Underweight	2 (6.5)
Sex	Female	11 (35.5)
	Male	20 (64.5)
Comorbidity	Type 2 diabetes	6 (19.4)
	Hypertension	7 (22.6)
Family history of CRC		3 (9.7)
Tumor size (cm)	2-5	17 (54.8)
	5-10	14 (45.2)
TNM stage	Stage II	9 (29)
	Stage III	18 (58.1)
	Stage IV	4 (12.9)
Tumor location	Left colon	14 (45.2)
	Right colon	9 (29)
	Transverse colon	2 (6.5)
	Rectum	6 (19.4)
Metastasis	Yes	6 (19.4)
	No	25 (80.6)
Treatment regimen	Single agent (5-FU)	13 (41.9)
	Capecitabine	8 (25.8)
	Ufur	4 (12.9)
	TS1	1 (3.2)
	Combination therapy (≥ 2 agents including 5-FU and oxaliplatin)	18 (58.1)
	mFOLFOX6	11 (35.5)
	XELOX	5 (16.1)
	B-mFOLFOX6	2 (6.5)
Therapy response	Complete response	25 (80.6)
	Partial response	3 (9.7)
	Disease progression	3 (9.7)

BMI: Body mass index; CRC: Colorectal cancer; 5-FU: 5-fluorouracil; TNM: Tumor, node and metastasis.

Table 2 Alpha diversity of gut microbiota in function of the clinical variables at the three timepoints

	Pielou’s evenness	Observed ASVs	Faith’s phylogenetic	Shannon’s entropy
Baseline (diagnosis; T0)
Age groups (year): 50-59 (n = 10), 60-69 (n = 10) vs 70-79 (n = 11)	0.729	0.428	0.260	0.668
BMI categories: Normal weight (n = 25) vs overweight (n = 4)	0.562	0.591	0.482	0.521
Sex: Male (n = 11) vs female (n = 20)	0.113	0.901	0.919	0.261
Type 2 diabetes: Yes (n = 6) vs no (n = 25)	0.827	0.671	0.643	0.827
Blood pressure: Hypertension (n = 7) vs normal (n = 24)	0.982	0.508	0.563	0.800
Tumor size (cm): 2-5 (n = 17) vs 5-10 (n = 14)	0.922	0.843	0.984	0.891
TNM stage: Stage II (n = 9), stage III (n = 18) vs stage IV (n = 4)	0.908	0.982	0.814	0.892
Tumor location: Left colon (n = 14), right colon (n = 9) vs rectum (n = 6)	0.464	0.562	0.599	0.671
Metastasis: Yes (n = 6) vs no (n = 25)	0.291	0.635	0.679	0.339
CEA: Normal (n = 27) vs elevated (n = 4)	0.589	0.227	0.376	0.476
After surgery (T1)
Age groups (year): 50-59 (n = 10), 60-69 (n = 10) vs 70-79 (n = 11)	0.608	0.902	0.705	0.851
BMI categories: Normal weight (n = 24) vs underweight (n = 5)	0.889	0.030a	0.044a	0.716
Sex: Male (n = 11) vs female (n = 20)	0.451	0.265	0.640	0.317
Type 2 diabetes: Yes (n = 6) vs no (n = 25)	0.053	0.635	0.643	0.105
Blood pressure: Hypertension (n = 7) vs normal (n = 24)	0.908	0.943	0.695	1.000
Tumor size (cm): 2-5 (n = 17) vs 5-10 (n = 14)	0.653	0.512	0.279	0.421
TNM stage: Stage II (n = 9), stage III (n = 18) vs stage IV (n = 4)	0.624	0.441	0.972	0.422
Tumor location: Left colon (n = 14), right colon (n = 9) vs rectum (n = 6)	0.050	0.008a	0.050	0.019a
After chemotherapy (T2)
Age groups (year): 50-59 (n = 10), 60-69 (n = 10) vs 70-79 (n = 11)	0.118	0.083	0.316	0.108
BMI categories: Normal weight (n = 25) vs overweight (n = 4)	0.482	0.635	0.604	0.482
Sex: Male (n = 11) vs female (n = 20)	0.528	0.591	0.823	0.670
Type 2 diabetes: Yes (n = 6) vs no (n = 25)	0.643	0.960	0.751	0.715
Blood pressure: Hypertension (n = 7) vs normal (n = 24)	0.104	0.015a	0.234	0.054
Tumor size (cm): 2-5 (n = 17) vs 5-10 (n = 14)	0.356	0.439	0.570	0.316
TNM stage: Stage II (n = 9), stage III (n = 18) vs stage IV (n = 4)	0.373	0.138	0.439	0.314
Tumor location: Left colon (n = 14), right colon (n = 9) vs rectum (n = 6)	0.992	0.555	0.519	0.993
CEA: Normal (n = 24) vs elevated (n = 7)	0.094	0.026a	0.139	0.061
Treatment regimen: Single agent (n = 13) vs combination therapy (n = 18)	0.106	0.149	0.332	0.115
Therapy response: Responder (n = 28) vs non-responder (n = 3)	0.635	0.124	0.681	0.503

^aP < 0.05.

P values were calculated with the Mann-Whitney U test (2 groups) and Kruskal-Wallis test (> 2 groups). Body mass index categories: Underweight (T0, T2) and overweight (T1) groups with ≤ 2 samples excluded due to insufficient sample size for statistical analysis. Tumor location: Transverse colon with 2 samples excluded. Carcinoembryonic antigen (CEA): Post-surgery (T1) CEA was not analyzed because concentration was elevated in only two patients. ASV: Amplicon sequence variant; BMI: Body mass index; TNM: Tumor, node and metastasis; CEA: Carcinoembryonic antigen.