Anatomical laterality of primary intestinal diffuse large B-cell lymphoma independently stratifies survival: New prognostic nomogram incorporating tumor location

Table 1 Baseline characteristics of primary intestinal diffuse large B-cell lymphoma patients in the SEER training cohort before and after propensity score matching, n (%)

Characteristics	Before propensity score matching			After propensity score matching
	Right side (n = 3358)	Left side (n = 474)	SMD	Right side (n = 1063)	Left side (n = 474)	SMD
Age			0.071			0.004
< 50	493 (14.7)	64 (13.5)		155 (14.6)	64 (13.5)
50-69	1269 (37.8)	168 (35.4)		396 (37.3)	168 (35.4)
70-89	1486 (44.2)	225 (47.5)		477 (44.9)	225 (47.5)
≥ 90	110 (3.3)	17 (3.6)		35 (3.3)	17 (3.6)
Gender			0.010			0.006
Female	1263 (37.6)	176 (37.1)		396 (37.3)	176 (37.1)
Male	2095 (62.4)	298 (62.9)		667 (62.7)	298 (62.9)
Race			0.060			0.039
White	2787 (83.0)	403 (85.0)		889 (83.6)	403 (85.0)
Black	177 (5.3)	24 (5.1)		55 (5.2)	24 (5.1)
Other	394 (11.7)	47 (9.9)		119 (11.2)	47 (9.9)
Stage			0.056			< 0.001
Stage I/II	2464 (73.4)	336 (70.9)		749 (70.5)	336 (70.9)
Stage III/IV	894 (26.6)	138 (29.1)		314 (29.5)	138 (29.1)
Radiation			0.284			0.002
Yes	192 (5.7)	67 (14.1)		128 (12.0)	67 (14.1)
No/unknown	3166 (94.3)	407 (85.9)		935 (88.0)	407 (85.9)
Surgery			0.581			0.001
Yes	2225 (66.3)	182 (38.4)		477 (44.9)	182 (38.4)
No	1133 (33.7)	292 (61.6)		586 (55.1)	292 (61.6)
Chemotherapy			0.099			0.002
Yes	2481 (73.9)	329 (69.4)		760 (71.5)	329 (69.4)
No/unknown	877 (26.1)	145 (30.6)		303 (28.5)	145 (30.6)

SMD: Standardized mean difference.

Table 2 Univariable and multivariable Cox analyses of overall survival in the SEER cohort before and after propensity score matching

Analysis	Characteristics	Before propensity score matching		After propensity score matching
		HR (95%CI)	P value	HR (95%CI)	P value
Univariate analysis	Age
	< 50	Reference		Reference
	50-69	1.77 (1.47-2.13)	< 0.001	1.37 (1.03-1.80)	0.028
	70-89	4.41 (3.69-5.27)	< 0.001	3.87 (2.98-5.02)	< 0.001
	≥ 90	10.20 (7.93-13.1)	< 0.001	8.47 (5.81-12.4)	< 0.001
	Gender
	Female	Reference		Reference
	Male	0.95 (0.87-1.04)	0.292	0.89 (0.77-1.02)	0.103
	Race
	White	Reference		Reference
	Black	0.96 (0.78-1.17)	0.670	1.02 (0.74-1.39)	0.922
	Other	0.88 (0.76-1.02)	0.100	0.69 (0.54-0.89)	0.004
	Stage
	Stage I/II	Reference		Reference
	Stage III/IV	1.48 (1.34-1.63)	< 0.001	1.59 (1.38-1.84)	< 0.001
	Laterality
	Right side	Reference		Reference
	Left side	1.31 (1.15-1.48)	< 0.001	1.22 (1.05-1.41)	0.008
	Radiation
	Yes	Reference		Reference
	No/unknown	0.88 (0.74-1.04)	0.124	0.98 (0.80-1.20)	0.857
	Surgery
	Yes	Reference		Reference
	No	1.19 (1.09-1.30)	< 0.001	1.14 (0.99-1.31)	0.057
	Chemotherapy
	Yes	Reference		Reference
	No/unknown	1.97 (1.80-2.17)	< 0.001	2.14 (1.86-2.46)	< 0.001
Multivariate analysis	Age
	< 50	Reference		Reference
	50-69	1.76 (1.46-2.12)	< 0.001	1.31 (0.99-1.72)	0.061
	70-89	4.14 (3.46-4.95)	< 0.001	3.29 (2.53-4.38)	< 0.001
	≥ 90	7.97 (6.15-10.31)	< 0.001	6.17 (4.18-9.12)	< 0.001
	Stage
	Stage I/II	Reference		Reference
	Stage III/IV	1.66 (1.50-1.83)	< 0.001	1.67 (1.44-1.93)	< 0.001
	Laterality
	Right side	Reference		Reference
	Left side	1.15 (1.01-1.31)	0.035	1.16 (1.01-1.35)	0.040
	Surgery
	Yes	Reference		Reference
	No	1.26 (1.15-1.39)	< 0.001	1.23 (1.06-1.42)	0.006
	Chemotherapy
	Yes	Reference		Reference
	No/unknown	1.80 (1.63-1.99)	< 0.001	1.86 (1.60-2.17)	< 0.001

HR: Hazard ratio; CI: Confidence interval.