Diagnosis and prognostic significance of extramural venous invasion in neuroendocrine tumors of the small intestine

The Usefulness of Elastin Staining to Detect Vascular Invasion in Cancer

Tumor prognosis hinges on accurate cancer staging, a pivotal process influenced by the identification of lymphovascular invasion (LVI), i.e., blood vessel and lymphatic vessel invasion. Protocols by the College of American Pathologists (CAP) and the World Health Organization (WHO) have been established to assess LVI in various tumor types, including, but not limited to, breast cancer, colorectal cancer (CRC), pancreatic exocrine tumors, and thyroid carcinomas. The CAP refers to blood vessel invasion as "angioinvasion" (vascular invasion) to differentiate it from lymphatic vessel invasion (lymphatic invasion). For clarity, the latter terms will be used throughout this review. The presence of lymphatic and/or vascular invasion has emerged as a pivotal prognostic factor; therefore, its accurate identification is crucial not only for staging but also for providing the patient with an honest understanding of his/her prognosis. Given the prognostic importance of the correct identification of LVI, specific staining techniques are employed to distinguish lymphatic vessel invasion from angioinvasion and to differentiate true LVI from artifact. These encompass hematoxylin and eosin (H&E) staining, elastic staining, Factor VIII staining, Ulex europaeus I agglutinin staining, CD31, CD34, D2-40, ERG, and D2-40 (podoplanin) immunohistochemical (IHC) stains among others. Based on a review of numerous publications regarding the efficacy of various methods for LVI detection, elastin staining demonstrated superior accuracy and prognostic value, allowing for more targeted treatment strategies. The clinical significance of accurately detecting LVI cannot be overstated, as it is strongly linked to higher cancer-related mortality and an increased risk of tumor recurrence. This review aims to examine the existing literature on the use of elastin stains in the detection of vascular invasion among different types of tumors and its prognostic value.

Prognostic differences in grading and metastatic lymph node pattern in patients with small bowel neuroendocrine tumors

PURPOSE

Neuroendocrine tumors of the small intestine (si-NET) describe a heterogenous group of neoplasms. Based on the Ki67 proliferation index si-NET are divided into G1 (Ki67 < 2%), G2 (Ki67 3-20%) and rarely G3 (Ki67 > 20%) tumors. However, few studies evaluate the impact of tumor grading on prognosis in si-NET. Moreover, si-NET can form distinct lymphatic spread patterns to the mesenteric root, aortocaval lymph nodes, and distant organs. This study aims to identify prognostic factors within the lymphatic spread patterns and grading.

METHODS

Demographic, pathological, and surgical data of 208 (90 male, 118 female) individuals with si-NETs treated at Charité University Medicine Berlin between 2010 and 2020 were analyzed retrospectively.

RESULTS

A total of 113 (54.5%) specimens were defined as G1 and 93 (44.7%) as G2 tumors. Interestingly, splitting the G2 group in two subgroups: G2 low (Ki67 3-9%) and G2 high (Ki67 10-20%), displayed significant differences in overall survival (OS) (p = 0.008) and progression free survival (PFS) (p = 0.004) between these subgroups. Remission after surgery was less often achieved in patients with higher Ki67 index (> 10%). Lymph node metastases (N +) were present in 174 (83.6%) patients. Patients with isolated locoregional disease showed better PFS and OS in comparison to patients with additional aortocaval and distant lymph node metastases.

CONCLUSION

Lymphatic spread pattern influences patient outcome. In G2 tumors, low and high grading shows heterogenous outcome in OS and PFS. Differentiation within this group might impact follow-up, adjuvant treatment, and surgical strategy.

Molecular factors, diagnosis and management of gastrointestinal tract neuroendocrine tumors: An update

The prevalence of gastrointestinal neuroendocrine tumors (GI-NETs) is increasing, and despite recent advances in their therapy, it remains inadequate in patients with advanced well-differentiated neuroendocrine tumors. These tumors present many challenges concerning the molecular basis and genomic profile, pathophysiology, clinicopathological features, histopathologic classification, diagnosis and treatment. There has been an ongoing debate on diagnostic criteria and clinical behavior, and various changes have been made over the last few years. Neuroendocrine carcinoma of the gastrointestinal system is a rare but highly malignant neoplasm that is genetically distinct from gastrointestinal system neuroendocrine tumors (NETs). The diagnosis and management have changed over the past decade. Emerging novel biomarkers and metabolic players in cancer cells are useful and promising new diagnostic tools. Progress in positron emission tomography-computerized tomography and scintigraphy with new radioactive agents (⁶⁴Cu-DOTATATE or ⁶⁸Ga-DOTATATE) replacing enough octreoscan, has improved further the current diagnostic imaging. Promising results provide targeted therapies with biological agents, new drugs, chemotherapy and immunotherapy. However, the role of surgery is important, since it is the cornerstone of management. Simultaneous resection of small bowel NETs with synchronous liver metastases is a surgical challenge. Endoscopy offers novel options not only for diagnosis but also for interventional management. The therapeutic option should be individualized based on current multidisciplinary information.

Evaluation of Pathologic Prognostic Factors in Neuroendocrine Tumors of the Small Intestine

The precise contributions of histopathologic features in the determination of stage and prognosis in small intestinal neuroendocrine tumors (NETs) are still under debate, particularly as they pertain to primary tumor size, mesenteric tumor deposits (TDs), and number of regional lymph nodes with metastatic disease. This single-institution series reviewed 162 patients with small bowel NETs (84 females, mean age: 60.3±12.0 y). All cases examined (100%) were immunoreactive for both chromogranin A and synaptophysin. Primary tumor size >1 cm (P=0.048; odds ratio [OR]=3.06, 95% confidence interval [CI]: 1.01-9.24) and lymphovascular invasion (P=0.007; OR=4.85, 95% CI: 1.53-15.40) were associated with the presence of lymph node metastasis. Conversely, TDs (P=0.041; OR=2.73, 95% CI: 1.04-7.17) and higher pT stage (P=0.006; OR=4.33, 95% CI: 1.53-12.28) were associated with the presence of distant metastasis (pM). A cutoff of ≥7 positive lymph nodes was associated with pM (P=0.041), and a thusly defined modified pN stage (pNmod) significantly predicted pM (P=0.024), compared with the prototypical pN (cutoff of ≥12 positive lymph nodes), which did not. Over a median follow-up of 35.7 months, higher pNmod (P=0.014; OR=2.15, 95% CI: 1.16-3.96) and pM (P<0.001; OR=11.00, 95% CI: 4.14-29.20) were associated with disease progression. Proportional hazards regression showed that higher pNmod (P=0.020; hazard ratio=1.51, 95% CI: 1.07-2.15) and pM (P<0.001; hazard ratio=5.48, 95% CI: 2.90-10.37) were associated with worse progression-free survival. Finally, Kaplan-Meier survival analysis demonstrated that higher pNmod (P=0.003), pM (P<0.001), and overall stage group (P<0.001) were associated with worse progression-free survival, while higher pM also predicted worse disease-specific survival (P=0.025). These data support requiring either chromogranin or synaptophysin, but not both, for small bowel NET diagnosis, the current inclusion of a 1 cm cutoff in primary tumor size and the presence of TDs in staging guidelines, and would further suggest lowering the cutoff number of positive lymph nodes qualifying for pN2 to 7 (from 12).

Epidemiologic Trends of and Factors Associated With Overall Survival for Patients With Gastroenteropancreatic Neuroendocrine Tumors in the United States

IMPORTANCE

Although the incidence and prevalence of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) have been thought to have increased during the past decades, updated epidemiologic and survival data are lacking.

OBJECTIVES

To conduct an epidemiologic and survival analysis of the largest cohort of patients with GEP-NETs using the latest data and to establish a novel nomogram to predict the survival probability of individual patients with GEP-NETs.

DESIGN, SETTING, AND PARTICIPANTS

In this cohort study, 43 751 patients with GEP-NETs diagnosed from January 1, 1975, to December 31, 2015, were identified from the Surveillance, Epidemiology, and End Results Program. Associated data were used for epidemiologic and survival analysis, as well as the establishment and validation of a nomogram to predict the survival probability of individual patients with GEP-NETs. The study cutoff date was December 31, 2018. Statistical analysis was performed from February 1 to April 30, 2020.

MAIN OUTCOMES AND MEASURES

Incidence, factors associated with overall survival, and a nomogram model for patients with GEP-NETs.

RESULTS

A total of 43 751 patients received a diagnosis of GEP-NETs from 1975 to 2015 (22 398 women [51.2%], 31 976 White patients [73.1%], 7097 Black patients [16.2%], 3207 Asian and Pacific Islander patients [7.3%], 270 American Indian and Alaska Native patients [0.6%], and 4546 patients of unknown race [10.4%]; mean [SD] age at diagnosis, 58 [15] years). The age-adjusted incidence rate of GEP-NETs increased 6.4-fold from 1975 to 2015 (annual percentage change [APC], 4.98; 95% CI, 4.75-5.20; P < .001). Furthermore, among site groups, the incidence of GEP-NETs in the rectum increased most significantly (APC, 6.43; 95% CI, 5.65-7.23; P < .001). As for stage and grade, the incidence increased the most in localized GEP-NETs (APC, 6.53; 95% CI, 6.08-6.97; P < .001) and G1 GEP-NETs (APC, 18.93; 95% CI, 17.44-20.43; P < .001). During the study period, the mean age at diagnosis for localized disease increased by 9.0 years (95% CI, 3.3-14.7 years; P = .002), which remained unchanged for regional and distant cases. On multivariable analyses, age, sex, marital status, and tumor size, grade, stage, and site were significantly associated with overall survival for patients with GEP-NETs (eg, patients with distant vs localized disease: hazard ratio, 10.32; 95% CI, 8.56-12.43; G4 vs G1 GEP-NET: hazard ratio, 6.37; 95% CI, 5.39-7.53). Furthermore, a nomogram comprising age, size, grade, stage, and site was established to predict the 3-year and 5-year survival probability, with the concordance indexes of 0.893 (95% CI, 0.883-0.903) for the internal validations and 0.880 (95% CI, 0.866-0.894) for the external validations. The receiver operating characteristic curve demonstrated that the nomogram exhibited better discrimination power than TNM classification (area under the curve for 3-year overall survival, 0.908 vs 0.795; for 5-year overall survival, 0.893 vs 0.791).

CONCLUSIONS AND RELEVANCE

In this study, the incidence and prevalence of GEP-NETs have continued to increase over 40 years, especially among patients with rectal GEP-NETs. In addition, this study suggests that a nomogram with 5 prognostic parameters may accurately quantify the risk of death among patients with GEP-NETs, indicating that it has satisfactory clinical practicality.