Colon and rectal cancer:An emergent public health problem

Colorectal cancer ranks third globally,with a high mortality rate.In the United States,and different countries in Europe,organized population screenings exist and include people between 50 and 74 years of age.These screenings have allowed an early diagnosis and consequently an improvement in health indicators.Colon and rectal cancer(CRC)is a disease of particular interest due to the high global burden associated with it and the role attributed to prevention and early diagnosis in reducing morbidity and mortality.This study is a review of CRC pathology and includes the most recent scientific evidence regarding this pathology,as well as a diagnosis of the epidemiological situation of CRC.Finally,the recommendation from a public health perspective will be discussed in detail taking into account the context and the most current recommendations.

Rectal Endometriosis Revealed by a Colonic Tumor Obstruction: A Case Report

Endometriosis is defined as the presence of endometrial tissue that is located outside the uterine cavity, associated with fibrosis and inflammatory reaction. The most common atypical locations are the gastrointestinal tract, urinary tract, lung, as well as abdominal surgical scars. Its diagnosis is still very difficult, especially when it manifests itself as an acute large bowel obstruction. We report the rare case of a 41-year-old patient diagnosed with acute colonic obstruction following a rectal tumor. She had undergone colonostomy even though colonoscopy biopsies were nonspecific, and a computed tomography (CT) scan was requested. It showed an adnexal heterogenous mass, therefore the patient had a laparotomy and a subtotal hysterectomy with bilateral salpingo-oophorectomy and a biopsy of the recto-colonic hinge. Histologic examination revealed a diagnosis of rectal endometriosis. The purpose of this work is to report a rare case of colonic endometriosis responsible for an acute large bowel obstruction.

Comparative analysis of the short and medium-term efficacy of the Da Vinci robot versus laparoscopic total mesangectomy for rectal cancer

BACKGROUND The Da Vinci robot-assisted surgery technique has been widely used in laparo-scopic mesangectomy for rectal cancer.However,the short-term efficacy of these procedures compared to traditional laparoscopic surgery remains controversial.The purpose of this study was to compare and analyze the short-and medium-term efficacy of Da Vinci robot and laparoscopic surgery in total mesangectomy(TME)for rectal cancer,so as to provide guidance and reference for clinical practice.AIM To investigate the safety and long-term efficacy of robotic and laparoscopic total mesorectal resection for the treatment of rectal cancer.METHODS The clinicopathologic data of 240 patients who underwent TME for rectal cancer in the Anorectal Department of People’s Hospital of Xinjiang Uygur Autonomous Region from August 2018 to March 2023 were retrospectively analyzed.Among them,112 patients underwent laparoscopic TME(L-TME)group,and 128 patients underwent robotic TME(R-TME)group.The intraoperative,postoperative,and follow-up conditions of the two groups were compared.RESULTS The conversion rate of the L-TME group was greater than that of the R-TME group(5.4%vs 0.8%,χ^(2)=4.417,P=0.036).The complication rate of the L-TME group was greater than that of the R-TME group(32.1%vs 17.2%,χ^(2)=7.290,P=0.007).The percentage of positive annular margins in the L-TME group was greater than that in the R-TME group(7.1%vs 1.6%,χ^(2)=4.658,P=0.031).The 3-year disease-free survival(DFS)rate and overall survival(OS)rate of the L-TME group were lower than those of the R-TME group(74.1%vs 85.2%,χ^(2)=4.962,P=0.026;81.3%vs 91.4%,χ^(2)=5.494,P=0.019);in patients with American Joint Committee on Cancer stage Ⅲ DFS rate and OS rate in the L-TME group were significantly lower than those in the R-TME group(52.5%vs 76.1%,χ^(2)=5.799,P=0.016;65.0%vs 84.8%,χ^(2)=4.787,P=0.029).CONCLUSION Compared with the L-TME group,the R-TME group had a better tumor prognosis and was more favorable for patients with rectal cancer,especially for patients with stage Ⅲ rectal cancer.

Endoscopic treatment and management of rectal neuroendocrine tumors less than 10 mm in diameter

Rectal neuroendocrine tumors(rNETs)measuring less than 10 mm in diameter are defined as small rNETs.Due to the low risk of distant invasion and metastasis,endoscopic treatments,including modified endoscopic mucosal resection,endoscopic submucosal dissection,and other transanal surgical procedures,are effective.This review article proposes a follow-up plan according to the size and histopathology of the tumor after operation.

Is lymphatic invasion of microrectal neuroendocrine tumors an incidental event?:A case report

BACKGROUND A rectal neuroendocrine tumor(rNET)is a malignant tumor originating from neuroendocrine cells.Currently,tumor size is the primary basis for assessing tumor risk.CASE SUMMARY This article reports the case of a 46-year-old male patient who underwent a colonoscopy that found a 3 mm rectal polypoid bulge.The pathological examination of a sample collected with biopsy forceps revealed a neuroendocrine tumor.Further endoscopic submucosal dissection rescue therapy was used.The presence of lymphatic vessels indicated that the tumor had infiltrated the negative resection margin.The lesion was located in the distal rectum near the anal canal.Therefore,to ensure the patient’s quality of life,follow-up observation was conducted after full communication with the patient.No tumor recurrence or distant metastasis has been found during the 13-mo follow-up after surgery.CONCLUSION Despite the presence of lymphatic invasion and extremely small diameter rNETs in our case,this phenomenon may not imply a higher risk of distant lymph node and organ metastasis.

Endoscopic mucosal resection with double band ligation versus endoscopic submucosal dissection for small rectal neuroendocrine tumors

BACKGROUND Endoscopic resection remains an effective method for the treatment of small rectal neuroendocrine tumors(NETs)(≤10 mm).Moreover,endoscopic mucosal resection(EMR)with double band ligation(EMR-dB),a simplified modification of EMR with band ligation,is an alternative strategy to remove small rectal NETs.AIM To evaluate the feasibility and safety of EMR-dB for the treatment of small rectal NETs(≤10 mm).METHODS A total of 50 patients with small rectal NETs,without regional lymph node enlargement or distant metastasis confirmed by endoscopic ultrasound,computerized tomography scan,or magnetic resonance imaging,were enrolled in the study from March 2021 to June 2022.These patients were randomly assigned into the EMR-dB(n=25)group or endoscopic submucosal dissection(ESD)group(n=25).The characteristics of the patients and tumors,procedure time,devices cost,complete resection rate,complications,and recurrence outcomes were analyzed.RESULTS There were 25 patients(13 males,12 females;age range 28-68 years old)in the EMR-dB group,and the ESD group contained 25 patients(15 males,10 females;age range 25-70 years old).Both groups had similar lesion sizes(EMR-dB 4.53±1.02 mm,ESD 5.140±1.74 mm;P=0.141)and resected lesion sizes(1.32±0.52 cm vs 1.58±0.84 cm;P=0.269).Furthermore,the histological complete resection and en bloc resection rates were achieved in all patients(100%for each).In addition,there was no significant difference in the complication rate between the two groups.However,the procedure time was significantly shorter and the devices cost was significantly lower in the EMRdB group.Besides,there was no recurrence in both groups during the follow-up period.CONCLUSION The procedure time of EMR-dB was shorter compared with ESD,and both approaches showed a similar curative effect.Taken together,EMR-dB was a feasible and safe option for the treatment of small rectal NETs.

Rectal neuroendocrine tumors:Current advances in management,treatment,and surveillance

Rectal neuroendocrine neoplasms(r-NENs)are considered among the most frequent digestive NENs,together with small bowel NENs.Their incidence has increased over the past few years,and this is probably due to the widespread use of endoscopic screening for colorectal cancer and the advanced endoscopic procedures available nowadays.According to the current European Neuroendocrine Tumor Society(ENETS)guidelines,well-differentiated r-NENs smaller than 10 mm should be endoscopically removed in view of their low risk of local and distant invasion.R-NENs larger than 20 mm are candidates for surgical resection because of their high risk of distant spreading and the involvement of the muscularis propria.There is an area of uncertainty regarding tumors between 10 and 20 mm,in which the metastatic risk is intermediate and the endoscopic treatment can be challenging.Once removed,the indications for surveillance are scarce and poorly codified by international guidelines,therefore in this paper,a possible algorithm is proposed.

Characteristics and long-term prognosis of patients with rectal neuroendocrine tumors

AIM: To analyze the clinicopathologic characteristics and prognostic factors of rectal neuroendocrine tumors.

Rectal neuroendocrine tumor with uncommon metastatic spread:A case report and review of literature

Neuroendocrine tumors of the gastrointestinal tract are rare neoplasms. Rectal neuroendocrine tumors consist approximately the 5%-14% of all neuroendocrine neoplasms in Europe. These tumors are diagnosed in relatively young patients,with a mean age at diagnosis of 56 years. Distant metastases from rectal neuroendocrine tumors are not very common. Herein we describe a case of a rectal neuroendocrine tumor which metastasized to the lung,mediastinum and orbit. This case underscores the importance of early identification and optimal management to improve patient's prognosis. Therefore,the clinical significance of this case is the necessity of physicians' awareness and education regarding neuroendocrine tumors' diagnosis and management.

Full-thickness excision using transanal endoscopic microsurgery for treatment of rectal neuroendocrine tumors

AIM:To assess the efficacy of full-thickness excision using transanal endoscopic microsurgery(TEM) in the treatment of rectal neuroendocrine tumors.METHODS:We analyzed the data of all rectal neuroendocrine tumor patients who underwent local full-thickness excision using TEM between December 2006 and December 2014 at our department. Data collected included patient demographics,tumor characteristics,operative details,postoperative outcomes,pathologic findings,and follow-ups. RESULTS:Full-thickness excision using TEM was performed as a primary excision(n = 38) or as complete surgery after incomplete resection by endoscopic polypectomy(n = 21). The mean size of a primary tumor was 0.96 ± 0.21 cm,and the mean distance of the tumor from the anal verge was 8.4 ± 1.4 cm. The mean duration of the operation was 57.6 ± 13.7 min,and the mean blood loss was 13.5 ± 6.6 m L. No minor morbidities,transient fecal incontinence,or wound dehiscence was found. Histopathologically,all tumors showed typical histology without lymphatic or vessel infiltration,and both deep and lateral surgical margins were completely free of tumors. Among 21 cases of complete surgery after endoscopic polypectomy,9 were histologically shown to have a residual tumor in the specimens obtained by TEM. No additional radical surgery was performed. Norecurrence was noted during the median of 3 years' follow-up.CONCLUSION:Full-thickness excision using TEM could be a first surgical option for complete removal of upper small rectal neuroendocrine tumors.

Clinical impact of atypical endoscopic features in rectal neuroendocrine tumors

AIM: To validate the association between atypical endoscopic features and lymph node metastasis(LNM).METHODS: A total of 247 patients with rectal neuroendocrine tumors(NETs) were analyzed. Endoscopic images were reviewed independently by two endoscopists, each of whom classified tumors by sized and endoscopic features, such as shape, color, and surface change(kappa coefficient 0.76 for inter-observer agreement). All of patients underwent computed tomography scans of abdomen and pelvis for evaluation of LNM. Univariate and multivariate analyses were performed to identify the factors associated with LNM. Additionally, the association between endoscopic atypical features and immunohistochemical staining of tumors was analyzed.RESULTS: Of 247 patients, 156(63.2%) were male and 15(6.1%) were showed positive for LNM. On univariate analysis, tumor size(P < 0.001), shape(P < 0.001), color(P < 0.001) and surface changes(P < 0.001) were significantly associated with LNM. On multivariate analysis, tumor size(OR = 11.53, 95%CI: 2.51-52.93, P = 0.002) and atypical surface(OR = 27.44, 95%CI: 5.96-126.34, P < 0.001) changes were independent risk factors for LNM. The likelihood of atypical endoscopic features increased as tumor size increased. Atypical endoscopic features were associated with LNM in rectal NETs < 10 mm(P = 0.005) and 10-19 mm(P = 0.041) in diameter. Immunohistochemical staining showed that the rate of atypical endoscopic features was higher in non L-cell tumors.CONCLUSION: Atypical endoscopic features as well as tumor size are predictive factors of LNM in patients with rectal NETs.

Neurofibromatosis type 1-associated multiple rectal neuroendocrine tumors: A case report and review of the literature

Neurofibromatosis type 1(NF-1) is commonly associated with benign or malignant tumors in both the central and peripheral nervous systems. However, rare cases of NF-1-associated multiplerectal neuroendocrine tumors have been reported. This report describes a case of a 39 year old female with NF-1 and intermittent hematochezia as a primary symptom. Physical examination showed multiple subcutaneous nodules and café au lait spots with obvious scoliosis of the back. Imaging examinations and colonoscopy found malformation of the left external iliac vein and multiple gray-yellow nodules with varying sizes and shapes in the rectal submucosal layer. Histological and immunohistochemical results suggested multiple rectal neuroendocrine tumors, a rare disease with few appreciable symptoms and a particularly poor prognosis. The patient with NF-1 presented here had not only multiple rectal neuroendocrine neoplasms but also vascular malformations, scoliosis and other multiple system lesions. This case therefore contributes to improving clinical understanding, diagnosis and treatment of related complications for patients with NF-1 who present with associated medical conditions.

Is endoscopic ultrasonography essential for endoscopic resection of small rectal neuroendocrine tumors?

AIM To evaluate the importance of endoscopic ultrasonography(EUS) for small(≤ 10 mm) rectal neuroendocrine tumor(NET) treatment.METHODS Patients in whom rectal NETs were diagnosed by endoscopic resection(ER) at the Pusan National University Yangsan Hospital between 2008 and 2014 were included in this study. A total of 120 small rectal NETs in 118 patients were included in this study. Histologic features and clinical outcomes were analyzed, and the findings of endoscopy, EUS and histology were compared. RESULTS The size measured by endoscopy was not significantly different from that measured by EUS and histology(r = 0.914 and r = 0.727 respectively). Accuracy for the depth of invasion was 92.5% with EUS. No patients showed invasion of the muscularis propria or metastasis to the regional lymph nodes. All rectal NETswere classified as grade 1 and demonstrated an L-cell phenotype. Mean follow-up duration was 407.54 ± 374.16 d. No patients had local or distant metastasis during the follow-up periods. CONCLUSION EUS is not essential for ER in the patient with small rectal NETs because of the prominent morphology and benign behavior.

Prognostic value of preoperative carcinoembryonic antigen/tumor size in rectal cancer

BACKGROUND Carcinoembryonic antigen(CEA)is a commonly used biomarker in colorectal cancer.However,controversy exists regarding the insufficient prognostic value of preoperative serum CEA alone in rectal cancer.Here,we combined preoperative serum CEA and the maximum tumor diameter to correct the CEA level,which may better reflect the malignancy of rectal cancer.AIM To assess the prognostic impact of preoperative CEA/tumor size in rectal cancer.METHODS We retrospectively reviewed 696 stage I to III rectal cancer patients who underwent curative tumor resection from 2007 to 2012.These patients were randomly divided into two cohorts for cross-validation:training cohort and validation cohort.The training cohort was used to generate an optimal cutoff point and the validation cohort was used to further validate the model.Maximally selected rank statistics were used to identify the optimum cutoff for CEA/tumor size.The Kaplan-Meier method and log-rank test were used to plot the survival curve and to compare the survival data.Univariate and multivariate Cox regression analyses were used to determine the prognostic value of CEA/tumor size.The primary and secondary outcomes were overall survival(OS)and disease-free survival(DFS),respectively.RESULTS In all,556 patients who satisfied both the inclusion and exclusion criteria were included and randomly divided into the training cohort(2/3 of 556,n=371)and the validation cohort(1/3 of 556,n=185).The cutoff was 2.429 ng/mL per cm.Comparison of the baseline data showed that high CEA/tumor size was correlated with older age,high TNM stage,the presence of perineural invasion,high CEA,and high carbohydrate antigen 19-9(CA 19-9).Kaplan-Meier curves showed a manifest reduction in 5-year OS(training cohort:56.7%vs 81.1%,P<0.001;validation cohort:58.8%vs 85.6%,P<0.001)and DFS(training cohort:52.5%vs 71.9%,P=0.02;validation cohort:50.3%vs 79.3%,P=0.002)in the high CEA/tumor size group compared with the low CEA/tumor size group.Univariate and multivariate analyses identified CEA/tumor size as an independent prognostic factor for OS(training cohort:hazard ratio(HR)=2.18,95%confidence interval(CI):1.28-3.73,P=0.004;validation cohort:HR=4.83,95%CI:2.21-10.52,P<0.001)as well as DFS(training cohort:HR=1.47,95%CI:0.93-2.33,P=0.096;validation cohort:HR=2.61,95%CI:1.38-4.95,P=0.003).CONCLUSION Preoperative CEA/tumor size is an independent prognostic factor for patients with stage I-III rectal cancer.Higher CEA/tumor size is associated with worse OS and DFS.

Risk factors of lymph node metastasis in rectal neuroendocrine tumors

Objective The aim of this study was to investigate the risk factors of lymph node metastasis in rectal neuroendocrine neoplasms(RNENs).Methods We enrolled 168 patients with RNENs as the research object,and their clinicopathological and survival data were collected.The risk factors affecting lymph node metastasis were analyzed retrospectively,and independent risk factors affecting prognosis were evaluated.Results Analysis showed that age,tumor diameter,tumor function,grade,and T stage were correlated with lymph node metastasis(P<0.05).Multiple logistic regression analysis showed that tumor size,grade,and T stage were independent risk factors for lymph node metastasis in patients with RNENs.Kaplan-Meier analysis showed that the 5-year overall survival(OS)of patients with lymph node metastasis was 40.0%(10/25),and that of patients without lymph node metastasis was 93.0%(133/143).The prognosis of RNENs patients with lymph node metastasis along with patients with large tumor diameter and high grade was poor.Cox multivariate analysis showed that tumor diameter(HR=1.985,P=0.008),grade(HR=3.416,P=0.004),T stage(HR=2.413,P=0.014),and lymph node metastasis(HR=3.119,P=0.000)were independent risk factors affecting the prognosis of patients with RNENs.Conclusion Tumor size,grade,and T stage are the main risk factors for lymph node metastasis and prognosis in patients with RNENs.These risk factors should be fully evaluated before surgery.

Effect of Tumor Infiltrating Lymphocyte on Local Control of Rectal Cancer after Preoperative Radiotherapy

Objective： To study the effect of tumor infiltrating lymphocytes at cancer nest on local control of rectal cancer after preoperative radiotherapy. Methods： From Jan. 1999 to Oct. 2007, a total of 107 patients with rectal cancer were reviewed. They were treated by preoperative radiotherapy, 30 Gy/10 fractions/12 days. Two weeks later, the patient underwent a surgical operation. Their pathological samples were kept in our hospital before and after radiotherapy. Lymphocyte infiltration （LI） degree, pathologic degradation and fibrosis degree after radiotherapy in paraffin section were evaluated under microscope. Results： After followed-up of 21 months （2-86 months）, a total of 107 patients were reviewed. Univariate analysis showed that lymphocyte infiltration （LI）, fibrosis and pathologic changes after radiotherapy were significant factors on local control. Logistic regression analysis showed that LI after radiotherapy was a significant effect factor on local control. Conclusion： LI, fibrosis and pathologic degradation after radiotherapy are significant for local control of rectal cancer after preoperative radiotherapy. LI after radiotherapy was a significantly prognostic index for local control of rectal cancer after preoperative radiotherapy.

Radical Operation and Everolimus Therapy for Rectal Neuroendocrine Tumor with Liver Metastases: A Case Report with Review of the Literature

Neuroendocrine tumors (NETs) are often misdiagnosed because they can involve any part of the body and have non-specific symptoms. Here, we report a case of a 39-year-old man with rectal neuroendocrine tumor (RNET) and hepatic metastases treated with a combination of radical surgery and Everolimus therapy. The patient complained of abdominal distension, pain, and constipation of one month duration. Enhanced CT scan of the abdomen, colonoscopy and Biopsy findings confirmed the diagnosis of rectal neuroendocrine tumor. As the anatomical structures were clear and the masses seemed to be resectable, we decided to initiate treatment with radical operation and Everolimus therapy. The patient has responded well to the treatment with no evidence of recurrence after 4 years of follow-up. This case is interesting because of the rarity of this neoplasm and its initial misdiagnosis as a giant hepatic carcinoma (hepatoma). It also demonstrates that a combination of curative surgical resection and Everolimus is a good option in a patient with large colorectal neuroendocrine tumors and massive hepatic metastases.

Mismatch repair protein expression and intratumoral budding in rectal cancer are associated with an increased pathological complete response to preoperative chemoradiotherapy: A case-control study

AIM To determine whether the association of rectal adenocarcinoma with a defective-mismatch repair system(dMMR) was associated with a pathological complete response(pCR) to preoperative chemoradiotherapy.METHODS A case-control study was designed with the aim of determining if patients with rectal adenocarcinoma with dM MR had an associated high pCR rate in response to neoadjuvant chemoradiotherapy(nCRT).RESULTS Seventy-two cases with pCR were compared against 144 controls without pCR. Across 216 cases, the mean age was 56.8 years, 140(64.8%) were men, and 63(29.2%) demonstrated the dMMR system. The pCR was associated with G1 tumors, dMMR, the absence of vascular invasion, and low tumor budding in the pretreatment biopsy. In a multivariant analysis, the factors associated with pCR were dMMR(OR: 2.61; 95%CI: 1.355-5.040, P = 0.004) and a low degree of tumor budding(OR: 2.52; 95%CI: 1.366-4.894, P = 0.025).CONCLUSION We found an independent association between dMMR and a low rate of tumor budding, with a higher rate of pCR, in the basal biopsies of patients with rectal carcinoma subjected to nCRT.

内镜切割吻合器在经肛门局部切除中低位直肠肿瘤中的应用

目的:回顾性分析中低位直肠肿瘤经肛门局部切除治疗中采用内镜切割吻合器的应用价值。方法:纳入我院经检查诊断的24例中低位直肠肿瘤患者,使用内镜切割吻合器对直肠肿瘤进行经肛门局部切除,总结分析患者临床病理资料特征及影像学诊断特点,评价该手术方式的安全性及可行性。结果:24例患者便潜血阳性者14例,症状以便血为主,肿瘤位置以前壁为主。随着肿瘤直径的增大,增强CT、MRI、EUS诊断的准确率升高,准确率方面EUS>MRI>增强CT,三者联合评估准确率提高。术后病理结果显示4例为上皮下来源肿瘤(SM层3例,MP层1例)。20例为上皮来源肿瘤,其中上皮来源良性肿瘤9例,为低级别管状腺瘤或低级混合状腺瘤;高级别上皮内瘤变2例;直肠癌9例,其中M层1例,SM层3例,MP层4例,S层1例。24例患者病灶完全切除率为100%,手术完成率为100%,无中转腹腔镜或开腹手术,手术平均时间、手术平均出血量、术后首次排气平均时间、术后住院平均天数分别为(29.25±6.42)min、(15.04±4.12)mL、(35.38±5.94)h、(3.17±0.92)d;术后7例患者出现WBC反应性升高,术后2~4天后均恢复正常,所有患者RBC及HGB计数较术前均降低,但均处于正常值范围,所有患者均无术后并发症。结论:内镜切割吻合器经肛门切除中低位直肠肿瘤具有操作时间短、副损伤小、术后应激反应低、恢复快的优势,该手术方式具有广泛的临床应用前景。

3.0T MRI对原发性直肠癌患者术前肿瘤局部浸润程度的评估价值

目的分析3.0T磁共振成像(MRI)对原发性直肠癌患者术前肿瘤局部浸润程度的评估价值。方法回顾性分析127例原发性直肠癌患者临床资料,患者术前均进行3.0T MRI扫描对直肠癌局部浸润征象做出分期诊断,并与术后病理组织学肿瘤T分期进行对照,以组织病理学结果作为金标准,计算3.0T MRI在评价肿瘤局部浸润程度的总的准确性及各分期的准确性、敏感度、特异度、阳性预测值、阴性预测值。结果127例原发性直肠癌患者中,经病理组织学确诊T2分期患者29例,T3分期患者55例,T4分期患者43例,3.0T MRI诊断T2分期患者31例,T3分期患者47例,T4分期患者49例,3.0T MRI诊断T分期与病理组织学诊断对照,kappa一致性为0.663,准确率为77.95%(99/127)。3.0T MRI对原发性直肠癌患者术前肿瘤局部浸润程度的诊断效能各有差异,T4分期的诊断效能较高,T2分期的诊断效能次之,T3分期的诊断效能较差,与病理组织学诊断对照,T2、T3、T4分期的kappa一致性分别为0.695、0.543、0.762,敏感度分别为79.31%、67.27%、90.70%,特异度分别为91.84%、86.11%、88.10%,准确率分别为88.98%、77.95%、88.98%,阳性预测值分别为74.19%、78.72%、79.59%,阴性预测值分别为93.75%、77.50%、94.87%。结论3.0T MRI对原发性直肠癌患者术前肿瘤局部浸润程度有较好的评估价值,尤其是T4分期的诊断效能较高。