Liao Timothy, Velanovich Vic
Division of General Surgery, Henry Ford Hospital, Detroit, MI 48202, USA.
Pancreas. 2007 Oct;35(3):243-8. doi: 10.1097/MPA.0b013e318068fc94.
Pancreatic cysts are being found with increasing frequency. Although symptomatic cysts should be resected, what to do about asymptomatic cysts is less clear. The purpose of this study was to determine threshold values to choose resection over observation for a patient with an asymptomatic pancreatic cyst.
Decision analysis assesses the consequences of a decision based on occurrence probabilities. This decision analysis assessed 1 decision, to resect or observe a patient with an asymptomatic pancreatic cyst. The consequences for resection are operative mortality/no operative mortality, short-term morbidity of patients surviving the operation, benign/malignant cyst, and life expectancy after resection of malignant lesions. The probabilities are based on the extant literature. The age-specific life expectancy for benign cysts was considered the same as for the general age-specific population from the 2002 United States Life Table. Because the operative mortality, distribution of benign versus malignant cysts, and life expectancy after resection or observation for malignant cysts vary, sensitivity analysis was done to assess the threshold values of these factors when resection becomes favored over observation.
The baseline decision analysis is based on the following assumptions: 30% of lesions are malignant, operative mortality rate is 3%, and the 5-year survival rate of resected malignant cysts is 50%. Varying on age, the risk of the cystic lesion being malignant to favor resection is greater than 11.6% to 15.5%, the operative mortality rate has to be less than 7.4% to 13.8%, and the life expectancy gain by resecting, rather than observing a malignant lesion, has to be greater than 3.49 to 5.38 years.
The decision to resect must be based on the surgeon's operative mortality rate, the predicted operative mortality for the individual patient, the probability that the lesion is malignant, and the survival difference between resecting and observing malignant cystic lesions. Overall, for resection to be recommended, the physician must believe that the risk that the lesion is malignant is approximately 15% or greater, that the life expectancy gained from resection be approximately 5 years or greater, and that the surgeons' operative mortality rate be approximately 8% or less.
胰腺囊肿的发现频率日益增加。虽然有症状的囊肿应予以切除，但对于无症状囊肿该如何处理尚不太明确。本研究的目的是确定对于无症状胰腺囊肿患者，选择切除而非观察的阈值。
决策分析基于发生概率评估决策的后果。该决策分析评估了一个决策，即对无症状胰腺囊肿患者进行切除或观察。切除的后果包括手术死亡率/无手术死亡率、手术存活患者的短期发病率、囊肿为良性/恶性以及恶性病变切除后的预期寿命。概率基于现有文献。良性囊肿的年龄特异性预期寿命被认为与2002年美国生命表中一般年龄特异性人群的相同。由于手术死亡率、良性与恶性囊肿的分布以及恶性囊肿切除或观察后的预期寿命各不相同，因此进行了敏感性分析，以评估当切除优于观察时这些因素的阈值。
基线决策分析基于以下假设：30%的病变为恶性，手术死亡率为3%，切除的恶性囊肿的5年生存率为50%。根据年龄不同，囊肿性病变为恶性而倾向于切除的风险必须大于11.6%至15.5%，手术死亡率必须小于7.4%至13.8%，并且切除而非观察恶性病变所带来的预期寿命增加必须大于3.49至5.38年。
切除的决策必须基于外科医生的手术死亡率、个体患者的预测手术死亡率、病变为恶性的概率以及切除与观察恶性囊肿性病变之间的生存差异。总体而言，若要推荐切除，医生必须认为病变为恶性的风险约为15%或更高，切除带来的预期寿命增加约为5年或更长，并且外科医生的手术死亡率约为8%或更低。
