Primary tumor location and survival in colorectal cancer: A retrospective cohort study

Table 2 Patient characteristics after propensity score matching

	Total (n = 792)	Cetuximab (n = 228)	Bevacizumab (n = 564)	P value
Age at index date1, years				0.923
Median	64.0	64.0	63.0
Sex, n (%)				0.914
Female	334 (42.2)	92 (40.4)	242 (42.9)
Male	458 (57.8)	136 (59.6)	322 (57.1)
Race, n (%)				0.905
Black or African American	71 (9.0)	22 (9.6)	49 (8.7)
White	549 (69.3)	158 (69.3)	391 (69.3)
Other race	111 (14.0)	32 (14.0)	79 (14.0)
Missing	61 (7.7)	16 (7.0)	45 (8.0)
Region, n (%)				0.620
Northeast	185 (23.4)	54 (23.7)	131 (23.2)
Midwest	113 (14.3)	26 (11.4)	87 (15.4)
South	253 (31.9)	75 (32.9)	178 (31.6)
West	158 (19.9)	48 (21.1)	110 (19.5)
Unknown	83 (10.5)	25 (11.0)	58 (10.3)
Practice type, n (%)				<0.001
Academic	35 (4.4)	0	35 (6.2)
Community	757 (95.6)	228 (100)	529 (93.8)
Site of disease, n (%)				1.000
Colon	630 (79.5)	180 (78.9)	450 (79.8)
Rectum	162 (20.5)	48 (21.1)	114 (20.2)
Group stage at initial diagnosis, n (%)				0.763
Stage I	9 (1.1)	3 (1.3)	6 (1.1)
Stage II	68 (8.6)	18 (7.9)	50 (8.9)
Stage III	245 (30.9)	79 (34.6)	166 (29.4)
Stage IV	458 (57.8)	124 (54.4)	334 (59.2)
Unknown	12 (1.5)	4 (1.8)	8 (1.4)
ECOG PS at index date1, 2, n (%)				0.379
0	197 (24.9)	61 (26.8)	136 (24.1)
1	130 (16.4)	30 (13.2)	100 (17.7)
2+	35 (4.4)	6 (2.6)	29 (5.1)
Missing	430 (54.3)	131 (57.5)	299 (53.0)
Modified CCI at index date1, 3, n (%)				0.861
0	650 (82.1)	185 (81.1)	465 (82.4)
1	104 (13.1)	32 (14.0)	72 (12.8)
2	34 (4.3)	10 (4.4)	24 (4.3)
3+	4 (0.5)	1 (0.4)	3 (0.5)
NRAS tested, n (%)	274 (34.6)	70 (30.7)	204 (36.2)	0.410
NRAS status among those tested4, n (%)				0.908
Mutation negative	268 (97.8)	68 (97.1)	200 (98.0)
Mutation positive	0	0	0
Results pending	1 (0.4)	0	1 (0.5)
Unknown	1 (0.4)	1 (1.4)	0
Unsuccessful/indeterminate	4 (1.5)	1 (1.4)	3 (1.5)
BRAF tested, n (%)	290 (36.6)	76 (33.3)	214 (37.9)	0.955
BRAF status among those tested4, n (%)				0.881
Mutation negative	248 (85.5)	64 (84.2)	184 (86.0)
Mutation positive	39 (13.4)	10 (13.2)	29 (13.6)
Results pending	1 (0.3)	0	1 (0.5)
Unknown	1 (0.3)	1 (1.3)	0
Unsuccessful/indeterminate	1 (0.3)	1 (1.3)	0
First-line chemotherapy backbone, n (%)				0.485
FOLFIRI	387 (48.9)	149 (65.4)	238 (42.2)
FOLFOX	405 (51.1)	79 (34.6)	326 (57.8)
History of adjuvant chemotherapy5, n (%)				0.789
No/not documented	519 (65.5)	140 (61.4)	379 (67.2)
Yes	273 (34.5)	88 (38.6)	185 (32.8)
First-line therapy duration6, days				0.424
Median	179.0	162.0	190.0
Length of follow-up7, days				0.533
Median	434.0	428.5	434.5
Side of colon, n (%)				0.868
Left side	283 (35.7)	78 (34.2)	205 (36.3)
Rectosigmoid	62 (7.8)	17 (7.5)	45 (8.0)
Rectum	154 (19.4)	47 (20.6)	107 (19.0)
Splenic flexure	19 (2.4)	5 (2.2)	14 (2.5)
Right side	231 (29.2)	68 (29.8)	163 (28.9)
Transverse colon	43 (5.4)	13 (5.7)	30 (5.3)

¹Index date defined as the start date (first administration or non-cancelled order) of a first-line regimen containing cetuximab or bevacizumab.

²ECOG PS may have been recorded up to 30 d prior, or up to 7 d after, the index date, whichever was closest to the index date.

³Charlson Comorbidity Index calculations exclude cancer diagnoses and include only comorbidities that were documented by the treating physician at any time prior to metastatic diagnosis date.

⁴Biomarker testing could occur at any point on, or up to, 28 d after the index date. For instances where multiple biomarker tests were available, the result from the successful test closest to the index date was used.

⁵Adjuvant therapy was only measured in non–stage IV patients.

⁶To account for potential censoring of patients on first-line therapy, the duration of first-line regimen was calculated using the following survival analysis methods: (1) The first administration or non-cancelled order for first-line therapy was the start date; (2) The last administration or non-cancelled order for first-line therapy was the end date; and (3) Patients were classified as having discontinued first-line therapy (i.e. an event) if any of the following occurred: (a) A patient started a subsequent line of therapy; (b) A patient died; or (c) A gap of more than 90 d occurred between a patient’s last administration or non-cancelled order for first-line therapy and the last activity date.

⁷Median follow-up time was calculated using observed time for all individuals, regardless of their outcome (i.e. not using survival analysis). Median was assessed using Kruskall-Wallis test. CCI: Charlson Comorbidity Index; ECOG PS: Eastern Cooperative Oncology Group performance status; FOLFIRI: 5-fluorouracil/leucovorin/irinotecan; FOLFOX: 5-fluorouracil/leucovorin/oxaliplatin.