Development and validation of a prognostic nomogram model for Chinese patients with primary small cell carcinoma of the esophagus

Table 1 Patient demographics and clinical characteristics

Variable	Primary cohort		Validation cohort
	n	%	n	%
Gender
Female	63	35.2	26	33.8
Male	116	64.8	51	66.2
Age, yr
≤ 60	74	41.3	32	41.6
> 60	105	58.7	45	58.4
Smoking history
No	122	68.2	59	76.6
Yes	57	31.8	18	23.4
Drinking history
No	134	74.9	64	83.1
Yes	45	25.1	13	16.9
Tumor location
Upper	23	12.9	8	10.4
Middle	111	62.0	46	59.7
Lower	45	25.1	23	29.9
Histology
Pure PSCE	106	59.2	57	74.1
Mixed PSCE	73	40.8	20	25.9
T stage
T1a/T1b	34	19.0	19	24.7
T2	63	35.2	31	40.2
T3/T4	82	45.8	27	35.1
N stage
N0	87	48.6	35	45.4
N1	64	35.8	30	39.0
N2/N3	28	15.6	12	15.6
Metastasis
No	136	75.9	60	77.9
Yes	43	24.1	17	22.1
Treatment methods
Surgery	155	86.6	68	88.3
Others	24	13.4	9	11.7
CD56
Negative	45	25.1	15	19.5
Positive	124	74.9	62	80.5
Syn
Negative	40	22.4	17	22.1
Positive	139	77.6	60	77.9
CgA
Negative	112	62.6	47	61.1
Positive	67	37.4	30	38.9

PSCE: Primary small cell carcinoma of the esophagus; T: Tumor invasion depth; N: Lymph node invasion; CD56: Neuronal cell adhesion molecule 56; Syn: Synaptophysin; CgA: Chromogranin A.

Table 2 Concordance index of nomogram model and tumor node metastasis stage for overall survival prediction in the primary and validation cohorts

Variable	Primary cohort		Validation cohort
	C-index (95%CI)	P value	C-index (95%CI)	P value
Nomogram model	0.659 (0.607-0.712)	0.033	0.700 (0.622-0.778)	0.041
7th TNM staging	0.591 (0.517-0.666)		0.605 (0.490-0.721)

C-index: Concordance index; CI: Confidence interval; TNM: Tumor node metastasis.

Table 3 Cox regression analysis for groups based on the model in the primary cohort

Groups	OS mean	1-yr (%)	3-yr (%)	5-yr (%)	Sig	HR (95%CI)
Low risk	71.7	83.4	57.5	33.4	-	-
Medium risk	19.8	66.4	31.7	21.4	0.004	1.93 (1.23-3.03)
High risk	10.03	34.8	4.4	-	0.000	5.47 (3.08-9.73)

OS: Overall survival; CI: Confidence interval; HR: Hazard ratio.