Difference in failure patterns of pT3-4N0-3M0 esophageal cancer treated by surgery vs surgery plus radiotherapy

Table 1 Clinical and pathological characteristics of patients of the two arms, n (%)

Variable	S arm (n = 174)	S + R arm (n = 56)	P value
Sex			0.656
Male	159 (91.4)	49 (87.5)
Female	15 (8.6)	7 (12.5)
Age (yr)			0.056
<60	106 (60.9)	42 (75.0)
≥60	68 (39.1)	14 (25.0)
Pathological differentiation			0.586
Poor	66 (37.5)	1 (1.8)
Moderate	97 (55.7)	33 (58.9)
Well	10 (5.7)	22 (39.3)
Tumor location			0.031a
Upper	15 (8.6)	3 (5.4)
Middle	98 (56.3)	22 (39.3)
Lower	61 (35.1)	31 (55.4)
Lymph node dissection			0.448
2-field resection	139 (79.9)	49 (87.5)
3-field resection	28 (16.1)	7 (12.5)
No. of LNs involved			0.740
≤2	113 (64.9)	35 (62.5)
≥3	61 (35.1)	21 (37.5)
No. of LNs dissected			0.569
<12	2 (1.1)	1 (1.8)
≥12	172 (98.9)	55 (98.2)
T stage			0.075
T3	164 (94.3)	48 (85.7)
T4	10 (5.7)	8 (14.3)
Chemotherapy			0.978
Yes	106 (60.9)	34 (60.7)

^aP < 0.05. S arm: Surgery alone arm; S + R arm: Surgery + postoperative radiotherapy arm; LN: Lymph node.

Table 2 Comparison of failure patterns for the two arms, n (%)

Type of failure	S arm (n = 174)	S + R arm (n = 56)	P value
Failure patterns			< 0.001
Distant metastasis	14 (8.0)	36 (64.3)
Locoregional recurrence	141 (81.0)	14 (25.0)
Mixed failure	19 (11.0)	6 (10.7)
Distant metastasis			< 0.001
Distant metastasis	33 (19.0)	42 (75.0)
Others	141 (81.0)	14 (25.0)
Locoregional failure			< 0.001
Locoregional recurrence	160 (92.0)	20 (78.3)
Others	14 (8.0)	36 (21.7)

S arm: Surgery alone arm; S + R arm: Surgery + postoperative radiotherapy arm; LN: Lymph node.

Table 3 Univariate and multivariate analyses for factors affecting survival

	Univariate analysis	Multivariate analysis
	Median DFS (mo)	χ2 value	P value	HR (95%CI)	P value
Sex				0.841 (0.532-1.328)	0.457
Male	9.5	0.309	0.579
Female	8
Age (yr)				0.712 (0.530-0.957)	0.024
< 60	9	1.023	0.312
≥ 60	9.5
Pathological differentiation				1.128 (0.094-1.934)	0.071
Poor	8	6.377	0.095
Moderate	10.4
Well	9.5
Tumor location				1.423 (0.849-2.386)	0.363
Upper	6.6	3.277	0.194
Middle	9.9
Lower	8.8
Lymph node dissection				0.531 (0.222-1.186)	0.107
2-field resection	9	3.462	0.177
3-field resection	8
No. of LNs involved				1.843 (1.369-2.482)	<0.001a
≤ 2	11	13.483	< 0.001
≥ 3	8
No. of LN dissected				1.460 (0.459-4.644)	0.522
< 12	7	0.656	0.418
≥ 12	9.5
Chemotherapy				0.732 (0.552-0.971)	0.031
Yes	8	1.769	0.183
No	10
T stage				0.697 (0.441-1.124)	0.132
T3	9	0.087	0.767
T4	8
Radiotherapy	-	-	-	0.667 (0.487-0.915)	0.012a

^aP < 0.05 in both univariate and multivariate analysis. S arm: Surgery alone arm; S + R arm: Surgery + postoperative radiotherapy arm; LN: Lymph node.