计数死亡率和发病率的生理学和手术严重性评分系统及其改进公式版在预测胰十二指肠切除术治疗壶腹周围肿瘤手术风险中的价值

Value of PUSSOM and P-POSSUM for the prediction of surgical operative risk in patients undergoing pancreaticoduodenectomy for periampullary tumors

目的：探讨计数死亡率和发病率的生理学和手术严重性评分（ POSSUM）系统及其改进公式版（ P-POSSUM）在预测胰十二指肠切除术治疗壶腹周围肿瘤手术风险中的价值。方法分别采用POSSUM和 P-POSSUM系统对1985年1月至2010年12月在中国医学科学院肿瘤医院腹部外科接受胰十二指肠切除术的432例壶腹周围肿瘤患者的临床资料进行评分，根据公式计算患者预期术后并发症和死亡的发生情况。采用受试者工作特征曲线（ ROC）以及不同危险因素群的实际并发症发生率或死亡率（O）与预测并发症发生率或死亡率（E）的比值来判断两种评分系统的预测效能，以Hosmer-Lemeshow检验判断两种评分系统的拟合优度。结果432例患者的生理学评分为（16．1±3．5）分，手术侵袭度评分为（19．6±2．7）分。 POSSUM和P-POSSUM系统预测死亡的ROC曲线下面积分别为0．893和0．888，差异无统计学意义（P＞0．05）。 POSSUM系统预测并发症的曲线下面积为0．575。POSSUM系统在预测并发症发生率为20％～40％时最为准确，O／E值为0．81。与POSSUM系统比较， P-POSSUM系统在预测术后死亡率上更具优势，在死亡率预测值＞15％时，预测较为准确，O／E值为1．00。结论 POSSUM和P-POSSUM系统对壶腹周围肿瘤行胰十二指肠切除术患者死亡的预测效能较好，而POSSUM系统对并发症的预测效能较差。可通过修改评分的常数和权重，建立适合胰十二指肠切除术的评分系统，以利于更好地预测手术风险，降低术后并发症和死亡率。

Objective To investigate the value of Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity（POSSUM）and a modification of the POSSUM system（P-P0SSUM） scoring system in predicting the surgical operative risk of pancreaticoduodenectomy for periampullary tumors. Methods POSSUM and P-POSSUM scoring systems were used to retrospectively evaluate the clinical data of 432 patients with periampullar tumors who underwent pancreaticoduodenectomy in the Department of Abdominal Surgery, Cancer Hospital,ChineseAcademy of Medical Sciences from January 1985 to December 2010. The predictive occurrence of postoperative complications and mortality rate were calculated according to the formula. ROC curve analysis and different group of risk factors were used to determine the discrimination ability of the two score systems, and to determine their predictive efficacy by comparing the actual and predictive complications and mortality rates, using Hosmer-Lemeshow test to determine the goodness of fit of the two scoring systems. Results The average physiological score of the 432 patients was 16.1±3.5, and the average surgical severity scorewas 19.6±2.7. ROC curve analysis showed that the area under ROC curve for mortality predicted by POSSUM and P-POSSUM were 0.893 and 0.888, showing a non-significant difference （ P〉0. 05 ） between them. The area under ROC curve for operative complicationspredicted by POSSUM scoring system was 0. 575. The POSSUM score system was most accurate for the prediction of complication rates of 20%-40%, showing the O/E value of 0.81. Compared with the POSSUM score system, P-POSSUM had better ability in the prediction of postoperative mortality, when the predicted value of mortality was greater than 15%, the predictive result was more accurate, and the O/E value was 1.00. Conclusions POSSUM and P-POSSUM scoring system have good value in predicting the mortality of patients with periampullary tumors undergoing pancreaticoduodenectomy, but a poorer value of POSSUM score system in prediction of complications. We can establish a more suitable scoring system for pancreaticoduodenectomy by modifying the score constant and weight, to better predict surgical risk and reduce the operative complications and mortality.