[Analysis of age cut-off and prognosis of early-onset gastric cancer in young patients].

To explore the optimal age cutoff for diagnosis and the prognosis of early-onset gastric cancer in young patients. Clinicopathological data of patients with gastric adenocarcinoma aged ≤45 years who had undergone radical gastrectomy in the Department of Gastric Surgery, Fudan University Shanghai Cancer Center from January 2013 to December 2018 were retrospectively collected. Patients with distant metastases, other malignant tumors, combined organ resection, gastric stump cancer, positive margin, and incomplete clinical or follow-up data were excluded. X-tile software analysis of the actual overall survival of the collected cases yielded an optimal cut-off of 32 years. Accordingly, the enrolled cases were divided into an early-onset young group (age ≤32 years) and young adult group (age >32 years). Clinicopathological characteristics, long-term survival, and postoperative recurrence were compared between the two groups. Univariate and multivariate analyses were performed using the Cox proportional hazards model to identify the factors affecting the prognosis of young patients with gastric cancer. The study cohort comprised 462 patients, including 256 (55.4%) women, 419 (90.7%) with middle and lower gastric cancers, and 343 (74.2%) with poorly differentiated tumors. There were 101 patients in the early-onset young group and 361 in the young adult group. These groups did not differ significantly in terms of sex, body mass index, tumor location, tumor size, surgical procedure, neurovascular invasion, or tumor stage (all >0.05). The proportion of patients with poorly differentiated tumors in the early-onset young group was significantly higher than that in the young adult group (89.1%[90/101] vs. 70.1%[253/361], χ=15.26, <0.001). All study patients completed 5 years of follow-up, the median duration of which was 101 months (61-133 months). Death or tumor recurrence occurred in 151 patients (32.7%), in 118 of whom the sites of recurrence and metastasis could be identified, 38 in the early-onset young group and 80 in the young adult group. Fifty-five (46.6%) patients developed peritoneal metastases and 40 (33.9%) hematogenous metastases. In the early-onset young group, 20 patients developed peritoneal metastases, 11 hematogenous metastases, five distant lymph node metastases, and two local recurrence. In the young adult group, 35 patients developed peritoneal metastases, 29 hematogenous metastases, six local recurrences, and 10 distant lymph node metastases. The 5-year overall survival and disease-free survival rates were significantly higher in the young adult group than in the early-onset young group (73.7% vs. 57.4%, =0.002 and 70.6% vs. 55.4%, =0.004, respectively). Cox multivariate analysis showed that age >32 years (HR=0.63, 95%CI: 0.43-0.90, =0.012) was an independent protective factor for overall survival, whereas later N stage (HR=1.67, 95%CI:1.09-2.57, =0.018) was an independent risk factor for overall survival after surgery (<0.05). Age >32 years (HR=0.60, 95%CI: 0.41-0.86, =0.006) was also an independent protective factor for disease-free survival, whereas later N stage was an independent risk factor (HR=1.69, 95%CI: 1.08-2.64, =0.021). Young patients with early-onset gastric cancer aged ≤32 years have worse tumor differentiation and prognosis.