The clinicopathological characteristics of the GC patients are compared in . There was no statistically significant difference between the YG and OG regarding family history of GC (5.9 vs. 6.3%, P=0.851). The proportion of tumor lesions located in the middle third or involving the whole stomach was significantly higher in the YG than in the OG (41.4 vs. 28.7%, P=0.0004; 13.6 vs. 9.0%, P=0.044, respectively), while the occurrence of tumor lesions in the lower third of the stomach was significantly higher in the OG than that in the YG (23.7 vs. 36.8%, P=0.0005). There was no statistically significant difference among the proportion of esophageal or duodenal invasion or of the occurrence of gastric stump (P=0.556, P=0.312 and P=0.071, respectively). Regarding macroscopic lesion types, Borrmann type 4 (diffuse infiltrative) lesions were more common in the YG compared with the OG (23.7 vs. 9.5%, P<0.0001), while Borrmann type 0 (superficial), type 1 (mass), type 2 (ulcerative) lesions were more common in the OG compared with the YG (36.7 vs. 46.2%, P=0.016; 0 vs. 2.4%, P=0.042; 6.5 vs. 11.8%, P=0.035, respectively). With regard to histological type, significantly more patients in the YG had poorly differentiated adenocarcinoma and signet ring cell carcinoma (39.1 vs. 25.4%, P=0.0002; 44.4 vs. 16.4%, P<0.0001, respectively), while more patients in the OG had papillary adenocarcinoma and tubular adenocarcinoma (0 vs. 4.5%, P=0.008; 14.2 vs. 51.1%, P<0.0001, respectively). Depth of invasion, peritoneal metastasis and stage of disease status had a significantly greater incidence in the YG than in the OG (P=0.010, P=0.0014 and P=0.019, respectively). Both groups had similar distributions with respect to lymph node metastasis, the mean number of metastatic lymph nodes, hepatic metastasis and distant metastasis.
Clinicopathological features of the gastric cancer patients.
Surgical characteristics are summarized in . In the YG, 152 patients (89.9%) had surgical resection while 3,411 (93.5%) of the OG patients had surgical resection (P=0.072); 112 (73.7%) YG patients and 2,728 (80.0%) OG patients had curative resection. The curative resection rate in the YG tended to be lower than that in the OG (P=0.059). The proportion of ‘open and closure’ in the YG was higher than that in the OG, due to the unresectable situation (P=0.037). The incidence of total gastrectomy and distal gastrectomy were similar in the YG and OG (P=0.138 and P=0.879, respectively). Proximal gastrectomy or partial resection (segmental or wedge gastrectomy), so-called reduction surgery, was frequently performed in the OG due to the comorbidities or general conditions present in this group (P=0.041 and P=0.005, respectively). There was a higher proportion of D2 and D3 lymphadenectomy in the YG compared with the OG (P=0.0015). Regarding the combined resection, pancreas tail, spleen, transverse colon and ovary were highly resected in the YG compared with the OG (P=0.0001, P=0.010, P<0.0001 and P<0.0001, respectively).
Surgical characteristics of the gastric cancer patients.
The overall median follow-up was 65.1 months (range 0–256 months). The 5-year overall survival rate in the YG and OG was 57.8 and 64.3%, respectively (). The OG survival rate was significantly higher than that of the YG (P=0.049). However, patients in the YG with curative resection had a similar 5-year survival rate to those in the OG with curative resection (88.0 vs. 85.8%, P=0.547) (). When the 5-year survival rate was compared with gender, there was no significant difference in survival for all patients or those in the OG (male 63.6% vs. female 64.9%, P=0.648; male 63.2% vs. female 66.6%, P=0.141) (). However, female patients in the YG showed a significantly lower survival rate than males in the YG (female 44.3% vs. male 73.1%, P=0.0002) (). When survival was determined according to the stage of the disease, there was no statistically significant difference in survival rate for all stages between the 2 groups (). However, stage IV patients in the YG had a slightly worse outcome than the pacients in the OG. The 1-year survival rate in the YG and OG was 15.6 and 24.2%, respectively and the 2-year survival rate was 4.4 and 10.4%, respectively. We also compared survival in the YG determined according to the stage (II–IV) between patients treated with chemotherapy (CG) and those not treated with chemotherapy (NCG). The 5-year survival rate of CG and NCG patients were as follows: stage II (70.3 vs. 75.0%, P=0.646); stage III (38.5 vs. 42.2%, P=0.568). The 2-year survival rate of CG and NCG patients at stage IV was 6.7 vs. 0% (P=0.612). There was no significant difference in survival rate for all stages between the 2 groups ().
Survival curves according to age for the younger group (YG) and the older group (OG). (A) All patients and (B) patients with curative resection.
Survival curves according to gender. (A) All patients, (B) older group (OG) and (C) younger group (YG).
Figure 4 Survival curves according to stage for the younger group (YG, solid line) and the older group (OG, dashed line). The 5-year survival rate of the YG and OG at stage I (100 vs. 97.3%, P=0.181), stage II (68.6 vs. 76.7%, P=0.286) and stage III (36.6 vs. (more ...)
Figure 5 Survival curves for the younger group (YG) according to stage on patients treated with chemotherapy (CG, solid line) and patients not treated with chemotherapy (NCG, dashed line). The 5-year survival rate of the CG and NCG at stage II was 70.3 vs. 75.0% (more ...)
Analyses of the prognostic factors for the YG in GC are presented in . Macroscopic type, depth of invasion, peritoneal metastasis, distant metastasis and curative resection emerged as independent prognostic factors (P=0.014, P=0.041, P=0.001, P=0.018 and P=0.021, respectively).
Analyses for prognostic factors for gastric cancer; in young patients.