2.

Survival analysis in the study population (estimated by the Kaplan-Meier method)

Characteristics	n	Mean survival (Mean±SD, month)	Log-rank test (P value)
Histology
Squamous cell carcinoma	7	21.4±2.8	0.11
Adenocarcinoma	5	43.2±15.3
Other	2	5.0±5.4
Age group (yr)
34-49	6	43.7±12.5	0.68
50-61	8	27.8±10.0
Tumor stage
Ⅰ-Ⅱ	7	47.4±12.2	0.001
ⅢA	3	11.0±6.4
ⅢB-Ⅳ	4	2.8±1.0
N (lymph node) status
N-	4	53.3±0	0.02
N+	10	12.6±2.5