The Clinicopathologic Characteristics And Prognostic Factors Of Pancreatic Neuroendocrine Tumors

Part ? Prognostic factors of long-term outcome in surgically resectable pancreatic neuroendocrine tumorsIntroduction:Pancreatic neuroendocrine tumors(PNETs)is a rare type of pancreatic tumors,accounting for about 1-3%of pancreatic tumors.The annual incidence of PNETs is about 1/10 million.With the development of computed tomography and magnetic resonance imaging technology,especially the application of fine needle aspiration biopsy under endoscopic ultrasound,the detection rate and diagnosis rate of PNETs are increasing.Meanwhile,the treatment for PNET is getting more and more attention.The treatment of PNETs includes operation,chemotherapy,biological therapy and molecular targeted therapy.Due to toxicity and lack of the large multicenter phase ?research in a particular part of gastroenteropancreatic neuroendocrine tumor,so chemotherapy can only be used for PNETs without other treatment.For the biological treatment,the anti-tumor effect of octreotide remains controversial.The role of molecular targeted drugs remains to be further studied.So surgery is still the main treatment for PNETs,and it is the only way to cure this kind of disease.The retrospective study of 728 PNETs by Hill showed 310 underwent radical surgery for early and advanced PNETs,while 425 cases had surgical indications.Compared with non-surgical treatment,surgery can bring significant survival benefit(the average survival time was 114 months and 35 months).McEntee et al also found that PNETs,even with metastasis,should also be treated with radical resection or palliative surgery,which can be benefit for the subsequent treatment.Unlike pancreatic cancer,PNETs with local progression or metastases are often recommended to receive tumor reduction surgery for the quality of life and survival time.In view of the importance of operation for PNETs,we chose PNETs who received operation in our hospital to analyze the prognosis.The operation mode of PNETs is mainly divided into tumor enucleation and radical resection(middle pancreatectomy,distal pancreatectomy,total pancreatectomy,or pancreatoduodenectomy),depending on a variety of factors,including tumor type,size,location and the relationship of main pancreatic duct.The advantages of enucleation is retaining more normal tissues,but may cause tumor residue and increasing incidence of pancreatic fistula.Meanwhile,radical rsection may have a better effect on tumor resection,but may cause the loss of normal pancreatic tissue.The research by Falconi suggested that there was no significantly different recurrence rate between the 24 PNETs underwent enucleation and 26 PNETs underwent middle pancreatectomy,but the the incidence of complications after middle pancreatectomy was higher.The average follow-up was 68 months,8%patients had local recurrence.So we will analyze the prognosis of PNETs patients with different surgical methods in the study.Furthermore,there are different opinions in the prognostic factors of PNET.Some scholars believed that tumor grade,symptoms,gender,age,tumor size,Ki-67 index,lymph node metastasis and distant metastasis were closely related with the prognosis of PNET,while other scholars does not agree with it.A retrospective study of 230 NF-PNET underwent surgical resection from 2008 to 1990 revealed that tumor size,stage and lymph node metastasis were closely related with survival time.In contrast,Bahra et al found that lymph node metastasis did not appear to be a prognostic factor for NF-PNET(P=0.81).Furthermore,a study of 1072 PNET by Rindi showed that gender was an important prognostic factor for PNET,but the study by Shin did not support that.In addition,whether the smaller PNETs should receive operation is still controversial.Some scholars believed that tumor resection should be performed for PNETs<2cm,if there was no surgical contraindications,while other scholars advocated the conservative treatment and regular follow-up.Lee et al analyzed 77 cases of NF-PNET<1cm.There was no increase of tumor size and disease progression during the follow-up of 45 months,while 56 cases of NF-PNET underwent surgery showed pancreatic leakage and other complications.Considering the risk of surgery,tumor location and concomitant diseases,PNETs<1.0cm without symptoms can be follow-up.As there are different opinions for the prognostic factors of PNETs and operation methods,this study retrospectively analyzed the PNETs at our institution to investigate the clinicopathologic features,surgical procedures and prognosis.Methods:The patients underwent surgical resection for PNETs were retrospectively reviewed from September 2002 to September 2013 at the First Affiliated Hospital,Zhejiang University School of Medicine.The diagnosis of PNET was made based on standard histologic criteria.The following characteristics were collected for each patient:Age,gender,presenting symptoms,location of primary tumor,type of surgery,operation time,blood loss,complications,pathologic features including tumor size,mitotic count and Ki-67 index,TNM stage,adjuvant therapy,the patient's disease status at last visit,and the most recent follow-up information.Surgical procedure,depending on tumor size and location,can be divided into local enucleation(EN),distal pancreatectomy(DP)with or without spleen reserved,pancreaticoduodenectomy(PD).To determine disease stage,we classified PNETs into the localized,regional,and distant groups.A localized PNET was defined as an invasive tumor confined entirely to the organ of origin.A regional PNET was defined as a tumor that extended beyond the limit of the organ of origin,directly into surrounding organs or tissue,involved regional lymph nodes,or fulfilled both of the aforementioned criteria.Finally,a distant PNET was defined as a tumor that spread to parts of the body remote from the primary tumor.Results were presented as median(range)and all statistical analyses were performed using the software SPSS 19.0(SPSS,Chicago,IL)for Windows.Overall survival(OS)was defined as the time span from initial diagnosis until death from any cause or last known contact.Disease-free survival(DFS)was defined as time from surgery to PNETs recurrence.OS and DFS analyses were performed by Kaplan-Meier methodology with log rank testing.Cox proportional hazard models were used to estimate hazard ratios for OS and DFS,and to determine independent risk factors.All tests were two-sided,with a P value of<0.05 considered statistically significant.Results:1.A total of 104 patients was selected,49(47.1%)were men and 55(52.9%)were women.The median age at presentation was 52(range,19-76)years.Of 104 PNETs,30(28.8%)were found incidentally during a health examination.The most common presentation of the symptomatic PNETs was abdominal pain in 31(29.8%)patients,followed by hypoglycemia in 28(27%),abdominal discomfort in 9(8.7%),jaundice in 4(3.8%)and diarrhea in 2(1.9%).2.All patients underwent surgical treatment,including 55 cases of DP(52.9%),32 cases of PD(30.8%)and 17 cases of EN(16.3%).The average age was 51.9 years.There was no significant relationship between the operation type and the age.The average amount of bleeding was 302.2ml,the intraoperative bleeding in PD group was significantly greater than the other 2 groups(P<0.001,P<0.001).the bleeding in EN group was lower than the other groups(P<0.001,P<0.001).The average operation time was 4.9 hours,the operation time of PD group was significantly longer than the other groups(P<0.001.,P<0.001);the average hospitalization time was 16.1 days,the postoperative hospitalization time in PD group was significantly longer than that in DP and EN group(P<0.001,P<0.001).No patients died during perioperative period.After operation,70 patients recovered well and no complications were found during the period of hospitalization.The other 34 cases had some complications,such as pancreatic fistula,postoperative infection,delayed gastric emptying,abdominal bleeding and so on.The incidence rate of pancreatic fistula in PD group was highest(31.25%),but there was no significant difference compared with the DP and EN group(P=0.33,P=0.3).The incidence rate of delayed gastric emptying in PD group was the highest(12.5%),significantly higher than that of DP group(P<0.05).3.The PNETs were located in the head of the pancreas(n=49,47.1%),followed by the tail(n=38,36.6%)and body(n=17,16.3%).The median size of PNETs was 3(range,0.8-19.0)cm.Most tumors were of low or moderate grade(93.3%,grade 1 or 2)and local or regional stage(92.3%).Eight(7.7%)patients were classified as having distant metastasis at initial diagnosis,while 17(17.3%)patients having distant metastasis during follow-up.The most frequent metastatic site was liver.The pathology showed lymph node metastasis in 20(19.2%)patients.4.The 1,3 and 5-year OS rate was 95%,85%and 73%,respectively.Meanwhile,the 1,3 and 5-year DFS rate was 86%,72%and 68%,respectively.OS and DFS were significantly different according to grade(grade 1,2 and 3)(P<0.001)and stage(local,regional,and distant disease)(P<0.001).Furthermore,patients with low Ki-67 index had superior OS and DFS compared to patients with high Ki-67 index(P<0.001).And,the presence of lymph nodes metastasis was predictive of inferior OS and DFS compared to those without lymph nodes metastasis(P<0.001).OS for PNETs was significantly influenced by resection margin status(P<0.001),while the surgical approach was not significantly associated with OS and DFS.5.In multivariable analysis,the significant factors associated with OS were stage,grade,lymph nodes status,Ki-67 index and resection margin status(all P<0.05).Meanwhile,stage,grade,lymph nodes status and Ki-67 index were prognostic factors for DFS(all P<0.05).Conclusion:1.Radical resection of pancreatic neuroendocrine tumor can achieve good long-term survival.However,surgical procedures were not associated with prognosis.2.Grade,stage,Ki-67 index and lymph nodes involvement are significant prognostic factors for OS and DFS in surgically resectable PNETs.Furthermore,accurate and detailed pathological assessment is important for guiding clinical treatment and prognosis.Part ? Expression and prognostic relevance of MMP-9 and DJ-1 in pancreatic neuroendocrine tumorsIntroduction:As the further research,we found that PNET has a series of malignant behaviors,which it can develop from inert slow growth or low malignancy to high metastasis in the long-term follow-up.With the development of imaging technology,the detection rate and diagnosis rate of PNETs are increasing.However,the symptoms of PNET are complex and diverse.It is often misdiagnosed and missed diagnosis,causing serious damage to the health of patients.At present,the diagnosis of PNETs is mainly based on imaging and detection of serum neuroendocrine markers,but they are not easy to judge the severity and prognosis.Therefore,there is an urgent need to discover more sensitive and specific biomarkers to assess the severity and prognosis of PNETs.Matrix metalloproteinase-9(MMP-9),as a member of the MMPs family,is playing a pivotal role in the degradation of basement membranes and extracellular matrix(ECM).It was found that there was no expression of MMPs in normal tissues,or only weakly expression in normal tissues.Compared with benign tumor and normal tissues,the expression of MMPs in malignant tumor cells significantly increased.Maatta et al reported that the mRNA expression of MMP-2 and MMP-9 in HCC tissue increased,and closely related with the degree of malignancy and prognosis.Chen et al found that the expression of MMP-9 decreased because of the knockdown of HMGB1 gene by lentivirus,leading apoptosis in ovarian cancer cells and inhibition of cancer cell proliferation,migration and invasion,which suggested that HMGB1 and MMP-9 were associated with tumor cell invasion.DJ-1,a multifunctional protein,is expressed in various tissues,especially in the tissues of testis,pancreas,kidney,heart and skeletal muscle,and associated with tumorigenesis.AMOUK et al found that the expression of DJ-1 protein was high in cervical cancer,and DJ-1 protein may be used as a marker for the detection of cervical cancer.Yuen et al analyzed the expression of DJ-1 in 81 cases of esophageal squamous cell carcinoma tumor tissue,31 cases of non cancerous esophageal epithelial tissue and 18 cases of lymph node metastasis.The expression of DJ-1 in cytoplasm of esophageal squamous cell carcinoma and lymph node metastasis was higher than that in non epithelial cancer.Compared with benign prostatic hyperplasia,the expression of DJ-1 in prostate cancer increased.So the expression of DJ-1 may be a candidate biomarker for the identification of benign and malignant prostate tumors.Though a number of studies have found that MMP-9 and DJ-1 were highly expressed in various tumor tissues,and closely related to the tumorigenesis,metastasis and prognosis.However,there are few studies about the expression of MMP-9 and DJ-1 in PNETs.The aim of this study is to investigate the expression of MMP-9 and DJ-1 in PNETs and their effect on the progression and prognosis.Methods:The patients underwent surgical resection for PNETs were retrospectively reviewed from January 2012 to January 2014 at the First Affiliated Hospital,Zhejiang University School of Medicine.The diagnosis of PNET was made based on standard histologic criteria.The expression of MMP-9 and DJ-1 in surgically resected specimens was detected by immunohistochemistry.The following characteristics were collected for each patient:Age,gender,presenting symptoms,location of primary tumor,type of surgery,pathologic features including tumor size,mitotic count and Ki-67 index,WHO grade,adjuvant therapy,the patient's disease status at last visit,and the most recent follow-up information.Surgical procedure,depending on tumor size and location,can be divided into local enucleation(EN),distal pancreatectomy(DP)with or without spleen reserved and pancreaticoduodenectomy(PD).Results were presented as median(range)and all statistical analyses were performed using the software SPSS 19.0(SPSS,Chicago,IL)for Windows.Overall survival(OS)and disease-free survival(DFS)were defined as the first part.Relationship between expression of MMP-9 and DJ-1 and the clinicopathologic characteristics was analyzed with chi square test.OS and DFS analyses were performed by Kaplan-Meier methodology with log rank testing.Cox proportional hazard models were used to estimate hazard ratios for DFS,and to determine independent risk factors.All tests were two-sided,with a P value of<0.05 considered statistically significant.Results:1.A total of 40 patients was selected,16 were men and 24 were women.The median age at presentation was 53(range,29-77)years.17(42.5%)were found incidentally during a health examination.The most common presentation of the symptomatic PNETs was abdominal pain in 11(27.5%)patients,followed by hypoglycemia in 7(17.5%),abdominal discomfort in 4(10%)and jaundice in 1(2.5%).All patients underwent radical surgical treatment,including 27 cases of DP,7 cases of PD and 6 cases of EN.The PNETs were located in the head of the pancreas(n=10),followed by the body(n=8)and tail(n=22).The median size of PNETs was 4(range,0.8-8.0)cm.Most tumors were of low or moderate grade(92.5%,grade 1 or 2).The pathology showed lymph node metastasis in 7 patients.Four(10%)patients were classified as having distant metastasis at initial diagnosis,while 12(30%)patients having distant metastasis during follow-up.2.Of 40 cases,19 cases of MMP-9 were positive(47.5%),While 21 cases of DJ-1 protein were positive(52.5%).Compared to those without lymph nodes metastasis,expression of MMP-9 and DJ-1 increased significantly in the patients with lymph nodes metastasis(P=0.026,P=0.006).Compared to those without distant metastasis,expression of MMP-9 and DJ-1 was also significantly increased in patients with distant metastasis(P=0.027,P=0.006).Expression of MMP-9 and DJ-1 in G2/G3 was significantly higher than that in G1(both P=0.027).In addition,there was no significant correlation between the expression level of MMP-9 and DJ-1 and the clinical pathological parameters such as gender,age,tumor location,tumor size or surgical procedure(P>0.05).3.The 1 and 3-year OS rate was 98%and 94%.Meanwhile,The 1 and 3-year DFS rate was 84%and 71%.Univariate analyses showed that lymph node,distant metastasis,WHO classification,expression of MMP-9 and expression of DJ-1 were significantly correlated with the DFS(all P<0.05).4.Further multivariate COX regression analysis showed that lymph node(HR=10.6,95%CI 2.24-50.16),distant metastasis(HR=9.76,95%CI 1.21-78.46)and WHO(HR=5.77,95%CI 1.22-27.21)classification were the independent risk factors of DFS(all P<0.05).Conclusion:MMP-9 and DJ-1 were highly expressed in PNETs,and played an important role in the malignant behavior.Higher expression of MMP-9 and DJ-1 was related with higher tumor malignancy and easier to invade the surrounding.