预后营养指数在老年胃癌患者治疗与预后中的意义

The value of preoperative prognostic nutritional index in elderly patients with gastric cancer

目的探讨预后营养指数（prognostic nutritional index，PNI）与老年胃癌患者临床病理特征、手术风险及预后的关系。方法回顾性分析2007年1月至2012年12月间天津医科大学第二医院收治的165例行根治手术治疗的老年（65岁及以上）胃癌患者的临床病理资料，计算PNI值。采用ROC曲线计算Youden指数，并得出PNI最佳cut—off值，根据最佳cut—off值将本组患者分为低PNI组与高PNI组，分析两组患者之间的临床病理特征、术后并发症及预后。结果165例胃癌患者的术前PNI平均值为46．1±5．3。当PNI值为46．4时，Youden指数最大，敏感度为78％，特异度为59％。两组在浸润深度（Х^2=6．732，P=0．009）、N分期（Х^2=13．191，P=0．004）及TNM分期（Х^2=12．137．P：0．000）上的差异具有统计学意义。两组术后并发症分别为19例和12例，差异无统计学意义（P〉0．05），在术后平均住院时间上的差异具有统计学意义（t=4．595，P=0．000）。单因素生存分析显示：PNI（P=0．000）、浸润深度（P=0．002）、N分期（P=0．000）、TNM分期（P=0．000）以及阳性软组织结节（P=0．031）与胃癌患者生存密切相关。多因素分析显示：PNI（P=0．016）和N分期（P=0．018）是胃癌患者术后的独立预后因素。结论PNI可以用来协助评估老年胃癌患者的营养状况及预后。

Objective To evaluate the impaet of preoperative prognostic nutritional index （PNI） on surgical outcomes and long-term survival of elderly patients with gastric cancer. Methods From Jan 2007 to Dee 2012, the clinieopathological data of 165 elderly patients （age 〉 65 years old） with gastric cancer undergoing radical gastrectomy in the Second Hospital of Tianjin Medical University were analyzed retrospectively. PNI value was calculated by serum albumin （g/L） ＋ 5 × lymphocyte count （ × 10^9/L）. The receiver operating characteristic （ ROC ） curve and Youden index was used to determine the cut-off value of PNI. Patients were then divided into low PNI group and high PNI group based on the cut-off value. The two groups were compared according to clinieopathologieal characteristics, postoperative complication and long- term survival. Results The mean PNI value was 46. 1 ± 5.3, When the PNI was 46.4, the Youden index was maximal, with a sensitivity of 78% and specificity of 59%. There were 79 patients in the low PNI group and 86 patients in high PNI group. No significant correlations between PNI and gender, age, BMI, pathological type, tumor diameter, extranodal metastasis and postoperative morbidity were observed. There were significant difference in the depth of invasion （Х^2= 6. 732, P = 0. 009）, N stage（Х^2 = 13. 191, P = 0. 004）, TNM stage（Х^2 = 12. 137, P =0. 000） and postoperative hospital stay （t =4. 595, P =0. 000）. By Kaplan-Meier method, PNI （ P = 0. 000）, depth of invasion （ P = 0. 002 ） , N stage （ P = 0. 000）, TNM stage（P = 0. 000） and extranodal metastasis（P = 0. 031 ） had significant impacts on overall survival. PNI （P= 0.016）and N stage （P = 0.018） were independent factors for predicting overall survival rate. Conclusions PNI helps in evaluating preoperative nutritional status and postoperative prognosis for elderly patients with gastric cancer.