Clinicopathological Characteristics,Surgical Management And Prognostic Factors Of Rectal Neuroendocrine Neoplasms In A Single Center

Background and ObjectiveNeuroendocrine tumors are a class of rare tumors that originate from neuroendocrine organs or cells and are highly heterogeneous.The most common sites are the gastrointestinal tract,which occurs in the rectum in China.Due to increased detection on screening endoscopy and the improvement of diagnostic techniques in recent years,the incidence of rectal neuroendocrine neoplasms appears to be increasing.However,due to the lack of uniform standards for the naming and classification of neuroendocrine tumors for a long time,clinicians have insufficient understanding of such diseases,and there are relatively few domestic and foreign research materials available for reference.The purpose of this study is to summarize the clinical features of rectal neuroendocrine tumors,the management strategies of surgical treatment and to explore the factors affecting the prognosis of the disease,so as to improve the clinician's understanding of rectal neuroendocrine tumors,and to conduct more standardized treatment in clinical practice.Materials and MethodsA retrospective analysis was conducted using the clinical data from 408 patienst treated for rectal neuroendocrine neoplasms in Changhai hospital of the Navy Military Medical University,from January 1999 to August 2018.The clinicopathological factors that may influence lymph node metastasis,distant metastasis and the prognosis were analyzed by univariate and multivariate analysis,while the selection strategies of various surgical treatments were compared.RESULTsA total of 408 patients with rectal neuroendocrine neoplasms were enrolled in the study,including 260 males(63.7%)and 148 females(36.3%).The male to female ratio was 1.76:1,and the median age was 51(18-78 years old).86.9% of the patients were located at a distance of ?7 cm from the anal verge,and 58.1% of the patients were asymptomatic at the time of diagnosis.The median tumor size was 8mm(2?90mm),including 292 cases(71.6%)with tumor diameter ?10mm,83 cases(20.3%)with tumor diameter 11?19mm,and 33 cases with tumor diameter ?20mm.Pathological grade G1/ G2/G3 accounted for 89.2%,8.1%,and 2.7%,respectively.During the follow-up period,a total of 43 patients found regional lymph nodes or distant metastases,the metastatic incidence of tumor size ?10mm was 2.4%,11?19mm was 15.6%,and ?20mm was 69.7%.Tumor size ? 2 cm(P = 0.043)and depth of invasion > T1(P = 0.016)were independent risk factors for lymph node metastasis.26 cases were distantly metastasized,liver metastasis accounted for 76.9%(multiple liver metastasis accounted for 75%),age >60 years old(P=0.017),tumor diameter?2cm(P<0.001),pathological grade(P<0.001)was independent risk factors for distant metastasis.Age >60 years old(P=0.017),tumor diameter ?2cm(P=0.013),pathological grade(P<0.001),lymph node metastasis(P=0.038),distant metastasis(P<0.001)was independent risk factors of poor prognosis.The five-year survival rate was 91.4%,the 10-year survival rate was 76.2%,and the 5-year survival rate with distant metastasis was 27.2%.The complete resection rate was significantly higher in the ESD group than in the EMR group(P=0.043),and there was no significant difference between the two groups(P=0.988).ConclusionMost patients with rectal neuroendocrine tumors are asymptomatic at diagnosis,with no specific clinical manifestations,and men are more likely to develop.The lesion is limited,less than 1cm and mostly G1 grade.The rectal NENs showed less metastasis,and the prognosis decreased significantly after metastasis.The most common distant metastasis site was the liver,which was more common with simultaneous and multiple liver metastases.Tumor size ? 2cm,depth of invasion,pathological grading is a reliable factor for predicting lymph node metastasis.Age > 60 years old,tumor size ? 2cm,pathological grading is an independent risk factor for distant metastasis.Age >60 years old,tumor size ? 2cm,pathological grade greater than G1,lymph node metastasis and distant metastasis are closely related to poor prognosis.For the selection strategy of surgical treatment of rectal neuroendocrine tumors,it is necessary to comprehensively consider various factors.Most patients have a good prognosis after local excision,endoscopic resection is safe and feasible.ESD is recommended as an endoscopic treatment for rectal neuroendocrine tumors.For patients with high risk of metastasis,radical resection is recommended.