Objective To explore the prognosis after radical resection for stage Ⅰ gastric cancer and the application value of adjuvant chemotherapy.
Methods The retrospective cohort study was conducted. The clinicopathological data of 3 353 patients with stage Ⅰ gastric cancer who were admitted to Fudan University Shanghai Cancer Center from January 2000 to December 2022 were collected. There were 2 369 males and 984 females, aged 60(range, 21-91) years. All patients underwent radical R0 resection. Observation indicators: (1) clinicopathological characteristics of patients; (2) influencing factors for postoperative prognosis of patients; (3) prognostic analysis of patients; (4) construction and validation of a predictive model for the efficacy of postoperative adjuvant chemotherapy. Comparison of count data between groups was conducted using the chi-square test. Univariate and multivariate analyses were performed using the Cox proportional hazards regression model. The Kaplan‑Meier method was used to calculate survival rates and draw survival curves, and the Log‑rank test was used for survival analysis. Based on the multivariate analysis result, a nomogram prediction model was constructed to predict survival benefit.
Results (1) Clinicopatho-logical characteristics of patients. The highly, moderately, and poorly differentiated tumors were observed in 16, 234, 396 cases of 646 patients aged <50 years and 279, 1 617, 811 cases of 2 707 pati-ents aged ≥50 years, respectively, showing a significant difference in degree of tumor differentiation between them (P<0.05). For 297 patients in stage T1N1M0, cases aged <50 years and ≥50 years were 71 and 226, cases of males and females were 184 and 113, cases with negative and positive vascular invasion were 37 and 260, cases with negative and positive nerve invasion were 275 and 22, cases without and with postoperative adjuvant chemotherapy were 222 and 75, respectively. The above indicators for 678 patients in stage T2N0M0 105, 573, 533, 145, 517, 161, 526, 152, 563, 115, respectively. There were significant differences in the above indicators between the two groups (P<0.05). (2) Influencing factors for postoperative prognosis of patients. Results of multivariate analysis showed that age ≥50 years, stage T2, moderately differentiated tumor, the number of lymph nodes dissected <16, positive vascular invasion, carcinoembryonic antigen (CEA) ≥5 μg/L, and CA19‑9 ≥37 U/mL were independent risk factors for disease‑free survival (DFS) after surgery for stage Ⅰ gastric cancer (hazard ratio=4.600, 1.555, 1.835, 1.362, 1.451, 1.571, 2.134, 95% confidence interval as 2.806-7.541, 1.205-2.006, 1.016-3.314, 1.059-1.753, 1.057-1.993, 1.100-2.243, 1.257-3.625, P<0.05). Age ≥50 years, stage T2, the number of lymph nodes dissected <16, positive vascular invasion, CEA ≥5 μg/L, and CA19‑9 ≥37 U/mL were independent risk factors for overall survival (OS) after surgery for stage Ⅰ gastric cancer (hazard ratio=5.208, 1.597, 1.373, 1.520, 1.464, 2.356, 95% confidence interval as 3.028-8.955, 1.231-2.072, 1.060-1.777, 1.099-2.104, 1.004-2.134, 1.385-4.009, P<0.05). Postoperative adjuvant chemotherapy was an independent protective factor for both DFS and OS after surgery for stage I gastric cancer (hazard ratio=0.361 0.297, 95% confidence interval as 0.177-0.736, 0.131-0.674, P<0.05). (3) Prognostic analysis of patients. According to the results of multi-variate analysis, among 3 353 patients, there were significant differences in 5‑year DFS rate and 10‑year OS rate between patients aged <50 years and ≥50 years (P<0.05). There were significant differences in 5‑year DFS rate and 10‑year OS rate among patients in TNM stage ⅠA and ⅠB (P<0.05). There were significant differences in 5‑year DFS rate and 10‑year OS rate among patients in stage T1N0M0, T1N1M0, T2N0M0 (P<0.05). There were significant differences in 5‑year DFS rate and 10‑year OS rate among patients with the highly, moderately, and poorly differentiated tumors (P<0.05). There were significant differences in 5‑year DFS rate and 10‑year OS rate among patients with the number of lymph lodes dissected <16 and ≥16 (P<0.05). There were significant differences in 5‑year DFS rate and 10‑year OS rate between patients with negative and positive vascular invasion (P<0.05). There were significant differences in 5‑year DFS rate and 10‑year OS rate between patients with and without postoperative adjuvant chemotherapy (P<0.05), among patients in stage T1N0M0, T1N1M0, T2N0M0 who received no postoperative adjuvant chemotherapy (P<0.05). For patients in stage T1N1M0, there was no significant difference in 5-year DFS rate and 10-year OS rate between patients with and without postoperative adjuvant chemotherapy (P>0.05).Results of stratified analysis showed that for patients aged ≥ 50 years, there were significant differences in 5‑year DFS rate and 10‑year OS rate between patients with and without postoperative adjuvant chemotherapy (P<0.05). For patients in stage T2N0M0, there were significant differences in 5‑year DFS rate and 10‑year OS rate between patients with and without postoperative adjuvant chemotherapy (P<0.05). For patients with positive vascular invasion, there were significant differences in 5‑year DFS rate and 10‑year OS rate between patients with and without postoperative adjuvant chemotherapy (P<0.05). (4) Construction and validation of a predictive model for the efficacy of adjuvant chemotherapy. A nomogram predictive model was constructed based on the multivariate analysis results of OS and used for calculating net benefits and distribution. Among the 3 096 patients without postoperative adjuvant chemotherapy, 1 009 cases had a predicted net benefit of >5%-10%, and 250 patients had a predicted net benefit >10%. The predicted survival analysis further verified that the predicted benefit of adjuvant chemotherapy was consistent with the prognosis of patients.
Conclusions Patients with age ≥50 years, stage T2 tumors, moderately differentiated tumor, the number of lymph nodes dissected <16, positive vascular invasion have worse survival prognosis postoperative. Postoperative adjuvant chemotherapy provides better prognosis in high‑risk patients. Patients in stage T1N1M0 have lower recurrence and survival risks, of whom with 1 metastatic lymph node is more suitable for follow-up rather than postoperative adjuvant chemotherapy.
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