Current Treatment Strategies and Future Directions for Extrapulmonary Neuroendocrine Carcinomas: A Review

Nasolabial flap with mucous membrane for repairing extensive lower lip tissue defect: A case report

The structural integrity of the lips is essential for both aesthetic appeal and oral functionality. Defects in this region, which may arise from a variety of causes, can significantly affect a patient's physical and psychological well-being. This case report introduces a novel surgical technique designed for the repair of substantial defects in the lower lip. The procedure utilizes a nasolabial flap in conjunction with the facial artery myomucous flap. This innovative approach addresses considerable lip-related defect challenges effectively. The report delineates the surgical steps implemented and highlights the successful reconstruction of the lower lip. Following the surgery, the patient demonstrated a positive recovery trajectory, marked by significant improvements in both lip symmetry and functionality, with no notable complications. The integration of the nasolabial flap with the mucous membrane has proven effective in the repair of extensive lip defects, particularly in the skin and mucous membrane areas adjacent to the corners of the mouth. This procedure not only facilitates the restoration of appearance and function but also reduces the risk of further surgical trauma. Additionally, the report underscores the necessity of thorough preoperative planning to mitigate complications at the donor site.

Molecular and Immunohistochemical Classification of Extrapulmonary Small Cell Neuroendocrine Carcinomas: A Study of 181 Cases

Extrapulmonary small cell neuroendocrine carcinoma (EP-SCNC) is a rare malignancy with a poor prognosis. Most patients with EP-SCNC have metastatic disease upon presentation, and their average overall survival (OS) is less than 12 months. Our study aimed to conduct a complex analysis of EP-SCNC. One hundred eighty-one EP-SCNC tissue samples were subjected to a complex analysis. One hundred fifty-five tumors were pure EP-SCNC, whereas 26 were combined tumors. Immunohistochemistry for ASCL1, NEUROD1, YAP1, POU2F3, Rb1, p53, cyclin D1, p16, PTEN, DLL3, PD-L1, CD56, synaptophysin, chromogranin A, and INSM1 was performed, and 128 samples were analyzed molecularly using next-generation sequencing, comprising DNA and RNA analyses. Detailed results on immunohistochemical and molecular analyses were provided for each primary origin of EP-SCNC separately. Median survival for the whole cohort of patients was 8.94 months. Patient age (≥70 years), tumor mutational burden <15, and TP53 and BRCA2 mutations were negative prognostic factors. High expression of ASCL-1 was associated with shorter OS, whereas high expression of YAP1 was associated with longer OS. Patients with genitourinary tumors had significantly better OS than those with gastrointestinal tract EP-SCNC tumors. Rb1 expression loss was detected more often in genitourinary tract SCNCs. In contrast, p16 overexpression was found more often in genitourinary tract SCNCs. POU2F3 expression was detected more often in combined tumors, whereas NEUROD1 was detected more often in pure EP-SCNC. Regarding "druggable markers," DLL3 was expressed in 66% of tumors and PD-L1 in 17.4%. Detailed analyses of different prognostic and predictive markers are needed to better understand EP-SCNC biology and create more personalized therapy to improve patient prognosis.

Single-cell RNA sequencing reveals tumor heterogeneity in small cell neuroendocrine cervical carcinoma

Small cell neuroendocrine cervical carcinoma (SCNECC) is an aggressive gynecological malignancy with poor prognosis. The precision therapeutic strategies for SCNECC are severely limited by the complex tumor microenvironment. Here, we mapped the single-cell landscape of a total of six samples from matched SCNECC cancerous foci and normal adjacent cervical tissues. Through analysis of 68,455 high-quality cells, malignant epithelial cells were identified with increased neuroendocrine differentiation and reduced keratinization. Within four epithelial cell clusters, the key transcription factors ASCL1, NEUROD1, POU2F3, and YAP1 defined molecular subtypes. Transitional trajectory among subtypes characterized two distinct carcinogenesis pathways in SCNECC. The P-type SCNECC showed potentially enhanced immune infiltration over other subtypes. Intercellular communication analysis identified several immune checkpoints and differentially expressed signaling pathways among subtypes. Through western blotting, the TC-YIK cell line was identified as an N-type SCNECC cell with high expression of SLFN11 and mTOR. Based on immunohistochemical staining of malignant subtyping markers, a cohort of 66 SCNECC patients from our hospital were divided into five subtypes. We further combined YAP1 expression with other clinicopathological factors (Cox p < 0.05) to establish a prognostic nomogram. Overall, these findings provide clues for tumorigenesis, precision treatments and prognostic prediction in SCNECC.

Correlation between p53 immunoexpression and TP53 mutation status in extrapulmonary small cell neuroendocrine carcinomas and its association with patient survival

Extrapulmonary small cell neuroendocrine carcinoma (EP-SCNC) is a rare malignancy with a poor prognosis. Despite its morphological similarity to lung small cell carcinomas, its oncogenesis remains uncertain. One hundred and seventy-one EP-SCNC were enrolled in a multicenter study, and all tissue samples underwent an immunohistochemical p53 analysis. One hundred twenty-five samples were molecularly analyzed using next-generation sequencing (NGS), comprising DNA and RNA analysis. p53 normal/wild type expression was detected in 68 cases (39.8%), whereas aberrant expression was detected in 103 cases (60.2%). Molecular TP53 alteration was detected in 92 out of 125 tumors (73.6%). The TP53 mutation was shown to be prognostic and associated with shorter overall survival (p = 0.041). The multivariate analysis of p53 and TP53 mutational status found that it impacted overall survival relative to distinct sites of tumor locations (p = 0.004 and p = 0.001, respectively). Age did not influenced survival in the multivariate analysis of p53 and TP53 (p = 0.002; p < 0.001 resp.). Among tumors with paired immunohistochemical and molecular results, 108 exhibited concordance between the immunohistochemical and molecular analysis, whereas 17 were discordant. Accordingly, p53 aberrant expression was tightly associated with a TP53 mutation (p < 0.001). In discordant cases, molecular analysis revealed no alteration in three tumors with p53 overexpression. In contrast, in 14 tumors with wild-type p53 expression, TP53 genetic alteration was detected. Possible causes of discordance are discussed in this manuscript. Furthermore, the incidence of aberrant p53 expression / TP53 molecular alteration was noticeably lower in EP-SCNC than in small-cell lung carcinomas. Therefore, in EP-SCNC, other driver mutations should be sought since personalized therapy can improve patient prognosis.

Unraveling molecular characteristics and tumor microenvironment dynamics of neuroendocrine prostate cancer

Prostate cancer (PCa) is the most prevalent malignancy and the second leading cause of cancer-related deaths among men. While adenocarcinoma of the prostate (adeno-PCa) is well-characterized, neuroendocrine prostate cancer (NEPC) remains poorly understood. Generally, NEPC is a rare but highly aggressive histological variant, however its limited patho-physiological understanding leads to insufficient treatment options associated with low survival rates for NEPC patients. Current treatments for NEPC, including platinum-based therapies, offer some efficacy, but there is a significant need for more targeted approaches. This review summarizes the molecular characteristics of NEPC in contrast to adeno-PCa, providing a comprehensive comparison. A significant portion of the discussion is dedicated to the tumor microenvironment (TME), which has recently been identified as a key factor in tumor progression. The TME includes various cells, signaling molecules, and the extracellular matrix surrounding the tumor, all of which play critical roles in cancer development and response to treatment. Understanding the TME's influence on NEPC could uncover new avenues for innovative treatment strategies, potentially improving outcomes for patients with this challenging variant of PCa.

Cancer plasticity in therapy resistance: Mechanisms and novel strategies

Therapy resistance poses a significant obstacle to effective cancer treatment. Recent insights into cell plasticity as a new paradigm for understanding resistance to treatment: as cancer progresses, cancer cells experience phenotypic and molecular alterations, corporately known as cell plasticity. These alterations are caused by microenvironment factors, stochastic genetic and epigenetic changes, and/or selective pressure engendered by treatment, resulting in tumor heterogeneity and therapy resistance. Increasing evidence suggests that cancer cells display remarkable intrinsic plasticity and reversibly adapt to dynamic microenvironment conditions. Dynamic interactions between cell states and with the surrounding microenvironment form a flexible tumor ecosystem, which is able to quickly adapt to external pressure, especially treatment. Here, this review delineates the formation of cancer cell plasticity (CCP) as well as its manipulation of cancer escape from treatment. Furthermore, the intrinsic and extrinsic mechanisms driving CCP that promote the development of therapy resistance is summarized. Novel treatment strategies, e.g., inhibiting or reversing CCP is also proposed. Moreover, the review discusses the multiple lines of ongoing clinical trials globally aimed at ameliorating therapy resistance. Such advances provide directions for the development of new treatment modalities and combination therapies against CCP in the context of therapy resistance.

A comparison of the outcomes of pulmonary versus extrapulmonary extensive-stage small cell carcinoma

BACKGROUND

Extrapulmonary small cell carcinomas (EPSCCs) are rare cancers, comprising 0.1-0.4% of all cancers. The scarcity of EPSCC studies has led current treatment strategies to be extrapolated from small cell lung cancer (SCLC), justified by analogous histological and clinical features.

AIMS

We conducted a retrospective cohort study comparing the outcomes of extensive-stage (ES) SCLC and EPSCC.

METHODS

Patients diagnosed with ES SCLC or EPSCC between 2010 and 2020 from four hospitals in Sydney were identified. Patients who received active treatment and best supportive care were included. The primary endpoint was overall survival (OS), and secondary endpoints were progression-free survival (PFS) and overall response rates (ORRs).

RESULTS

Three hundred and eighty-four patients were included (43 EPSCC vs. 340 SCLC). EPSCC were of genitourinary (n = 15), unknown primary (n = 13) and gastrointestinal (n = 12) origin. Treatment modalities for EPSCC compared to SCLC included palliative chemotherapy (56% vs 73%), palliative radiotherapy (47% vs 59%) and consolidation chest radiotherapy (10% of SCLC). Overall, median OS was 6.4 versus 7 months for EPSCC versus SCLC respectively, but highest in prostate EPSCC (25.6 months). Of those who received chemotherapy (22 EPSCC vs 233 SCLC), median OS was 10.4 versus 8.4 months (HR OS 0.81, 95% confidence interval (CI): 0.5-1.31, P = 0.38); PFS was 5.4 versus 5.5 months (HR PFS 0.93, 95% CI: 0.58-1.46, P = 0.74) and ORR were 73% versus 68%.

CONCLUSIONS

EPSCC and SCLC appeared to have comparable OS and treatment outcomes. However, the wide range of OS in EPSCC highlights the need for an improved understanding of its genomics to explore alternative therapeutics.

Small Cell Oesophageal Carcinoma: A Retrospective Case Series From a UK Tertiary Centre and a Review of the Literature

Background Small cell oesophageal carcinoma (SCEC), a rare neuroendocrine malignancy, presents various challenges in diagnosis and treatment. The condition is characterised by rapid dissemination, a marked responsiveness to chemotherapy, and a guarded prognosis. While the European Neuroendocrine Tumour Society has recommended platinum-based chemotherapy, ongoing debates on optimal strategies and the lack of clear guidelines underscore the need for further comprehensive research efforts. Methods This study retrospectively analysed 12 cases of localised pure SCEC treated at a UK tertiary care centre between 2006 and 2020. We systematically analysed and categorised the cases based on stage, performance status, and patient age. This comprehensive approach enabled a nuanced examination of overall survival (OS), thereby providing valuable insights into the differences between outcomes. Results The study revealed a median OS of 12.01 months for treated non-metastatic cases, highlighting the challenges of SCEC management. Conversely, treated metastatic cases exhibited a mean survival of 9.15 months, which contrasts starkly with the 2.55 months demonstrated by those receiving best supportive care (BSC). These figures underscore the urgency for refined strategies in handling advanced localised disease and the need to continue research endeavours to devise methods to enhance the precision and optimise outcomes beyond the presented data. Conclusion Based on our findings, the combination of chemoradiotherapy and surgery to manage SCEC holds promise; however, further research is needed to optimise the management approach. The lack of clear guidelines underscores the imperative for personalised treatment approaches.

Small cell neuroendocrine carcinoma of the cervix: From molecular basis to therapeutic advances

Small cell neuroendocrine carcinoma of the cervix (SCNECC) is an uncommon but aggressive uterine malignancy, the cause of which is generally associated with human papillomavirus (HPV) infection. A lack of clinical trials and evidence-based treatment guidelines poses therapeutic challenges to this rare tumor. At present, published data remain limited to case series and case reports. While clinical management has traditionally followed those of small cell neuroendocrine (SCNE) lung cancer relying on surgery, chemoradiation, and systemic chemotherapy, the prognosis remains dismal. Immune checkpoint inhibitors (ICIs), such as monoclonal antibodies that target programmed death-1 (PD-1) or programmed death-ligand 1 (PD-L1), atezolizumab and durvalumab have proven effective in extensive-stage SCNE lung cancer. Moreover, pembrolizumab has also proven beneficial effects when added onto chemotherapy in metastatic and recurrent HPV-associated non-SCNE cervical cancer. It holds promise to use ICIs in combination with chemoradiation to improve the clinical outcomes of patients with SCNECC. Future advances in our understanding of SCNECC biology - associated with the study of its genomic and molecular aberrations as well as knowledge from SCNE of lung and other extrapulmonary sites- would be helpful in discovering new molecular targets for drug development. Collaborative efforts and establishment of a SCNECC-specific biobank will be essential to achieve this goal.

Outcomes of extensive stage extrapulmonary small cell cancer

BACKGROUND

Extrapulmonary small cell cancer (EPSCC) is a rare malignancy with an incidence of approximately 0.1%-0.4% of all cancers. Treatment of this disease is often based on small cell lung cancer.

AIMS

We aimed to investigate real-world clinical outcomes of patients with extensive-stage (ES) ESPCC.

METHODS

Patients diagnosed with ES EPSCC between 2010 and 2020 from multiple centres in New South Wales were identified. Patient, disease and treatment characteristics were collected and presented using descriptive statistics. Survival was analysed using the Kaplan-Meier method. Univariate and multivariate Cox regression hazard models were used to identify potential prognostic factors.

RESULTS

Sixty eligible ES EPSCC patients were identified, including 65% male and 35% female. The mean age was 69 years (range 37-88). Forty-five per cent were never smokers, 42% ex-smokers and 13% current smokers, and 17% of patients had limited-stage disease prior to development of ES disease. The most common primary sites were genitourinary (42%; mainly prostate (n = 14) and bladder (n = 10)), gastrointestinal (28%; mainly oesophagus (n = 5) and colon (n = 4)) and unknown primary (22%). Treatments received included palliative chemotherapy (67%), palliative radiotherapy (53%), palliative surgery (13%) and best supportive care alone (13%). The median overall survival (OS) was 8.0 months. The median progression-free survival was 5.4 months, and response rate to first-line chemotherapy was 65%. Platinum-based chemotherapy was prognostic of longer OS (HR 0.27, CI 0.12-0.60, P = 0.001).

CONCLUSIONS

Patients with ES EPSCC had good response to palliative chemotherapy, but OS remained poor. Further research is required to improve the prognosis in this population.

Potent molecular-targeted therapies for gastro-entero-pancreatic neuroendocrine carcinoma

Neuroendocrine neoplasms (NENs), which are characterized by neuroendocrine differentiation, can arise in various organs. NENs have been divided into well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs) based on morphological differentiation, each of which has a distinct etiology, molecular profile, and clinicopathological features. While the majority of NECs originate in the pulmonary organs, extrapulmonary NECs occur most predominantly in the gastro-entero-pancreatic (GEP) system. Although platinum-based chemotherapy is the main therapeutic option for recurrent or metastatic GEP-NEC patients, the clinical benefits are limited and associated with a poor prognosis, indicating the clinically urgent need for effective therapeutic agents. The clinical development of molecular-targeted therapies has been hampered due to the rarity of GEP-NECs and the paucity of knowledge on their biology. In this review, we summarize the biology, current treatments, and molecular profiles of GEP-NECs based on the findings of pivotal comprehensive molecular analyses; we also highlight potent therapeutic targets for future precision medicine based on the most recent results of clinical trials.

Poorly differentiated orbital neuroendocrine carcinoma

A man in his 70s presented with painless bilateral eyelid oedema and vertical diplopia. Evaluation showed a restrictive pattern of extraocular motility testing with MRI demonstrating significant enlargement of the right superior rectus and left superior oblique muscles along with right orbital fat stranding. Subsequent right orbital biopsy revealed poorly differentiated high-grade neuroendocrine carcinoma without a systemic primary site on further diagnostic workup. The patient was treated with carboplatin and etoposide and passed away from an infection a month after diagnosis. This case along with a review of other published cases highlights the varied presentation of orbital neuroendocrine carcinomas that may mimic a broad differential of orbital processes, thus requiring careful diagnostic workup. Subsequently, additional considerations in metastatic evaluation should be based on tumour histological features.

An integrated cellular and molecular model of gastric neuroendocrine cancer evolution highlights therapeutic targets

Gastric neuroendocrine carcinomas (G-NEC) are aggressive malignancies with poorly understood biology and a lack of disease models. Here, we use genome sequencing to characterize the genomic landscapes of human G-NEC and its histologic variants. We identify global and subtype-specific alterations and expose hitherto unappreciated gains of MYC family members in a large part of cases. Genetic engineering and lineage tracing in mice delineate a model of G-NEC evolution, which defines MYC as a critical driver and positions the cancer cell of origin to the neuroendocrine compartment. MYC-driven tumors have pronounced metastatic competence and display defined signaling addictions, as revealed by large-scale genetic and pharmacologic screening of cell lines and organoid resources. We create global maps of G-NEC dependencies, highlight critical vulnerabilities, and validate therapeutic targets, including candidates for clinical drug repurposing. Our study gives comprehensive insights into G-NEC biology.

Combination therapy with topotecan, paclitaxel, and bevacizumab improves progression-free survival in patients with recurrent high-grade neuroendocrine cervical cancer: a Neuroendocrine Cervical Tumor Registry (NeCTuR) study

BACKGROUND

Recurrent high-grade neuroendocrine cervical cancer has a very poor prognosis and limited active treatment options.

OBJECTIVE

This study aimed to evaluate the efficacy of the 3-drug regimen of topotecan, paclitaxel, and bevacizumab in women with recurrent high-grade neuroendocrine cervical cancer.

STUDY DESIGN

This retrospective cohort study used data from the Neuroendocrine Cervical Tumor Registry (NeCTuR), which include data abstracted directly from medical records of women diagnosed with high-grade neuroendocrine carcinoma of the cervix from English- and Spanish-speaking countries. The study compared women with recurrent high-grade neuroendocrine cervical cancer who received the topotecan, paclitaxel, and bevacizumab regimen as first- or second-line therapy for recurrence and women with recurrent high-grade neuroendocrine cervical cancer who received chemotherapy but not the topotecan, paclitaxel, and bevacizumab regimen. Patients continued chemotherapy until disease progression or the development of unacceptable toxic effects. Progression-free survival from the start of therapy for recurrence to the next recurrence or death, overall survival from the first recurrence, and response rates were evaluated.

RESULTS

The study included 62 patients who received the topotecan, paclitaxel, and bevacizumab regimen as first- or second-line therapy for recurrence and 56 patients who received chemotherapy but not the topotecan, paclitaxel, and bevacizumab regimen for recurrence. The median progression-free survival rates were 8.7 months in the topotecan, paclitaxel, and bevacizumab regimen group and 3.7 months in the non-topotecan, paclitaxel, and bevacizumab regimen group, with a hazard ratio for disease progression of 0.27 (95% confidence interval, 0.17-0.48; P<.0001). In the topotecan, paclitaxel, and bevacizumab regimen group, 15% of patients had stable disease, 39% of patients had a partial response, and 18% of patients had a complete response. Compared with patients in the non-topotecan, paclitaxel, and bevacizumab regimen group, significantly more patients in the topotecan, paclitaxel, and bevacizumab regimen group remained on treatment at 6 months (31% vs 67%, respectively; P=.0004) and 1 year (9% vs 24%, respectively; P=.02). The median overall survival rates were 16.8 months in the topotecan, paclitaxel, and bevacizumab regimen group and 14.0 months in the non-topotecan, paclitaxel, and bevacizumab regimen group, with a hazard ratio for death of 0.87 (95% confidence interval, 0.55-1.37).

CONCLUSION

Combination therapy with topotecan, paclitaxel, and bevacizumab was an active regimen in women with recurrent high-grade neuroendocrine cervical cancer and improved progression-free survival while decreasing the hazard ratio for disease progression.

All Together Now: Standardization of Nomenclature for Neuroendocrine Neoplasms across Multiple Organs

Neuroendocrine neoplasms (NENs) span virtually all organ systems and exhibit a broad spectrum of behavior, from indolent to highly aggressive. Historically, nomenclature and grading practices have varied widely across, and even within, organ systems. However, certain core features are recapitulated across anatomic sites, including characteristic morphology and the crucial role of proliferative activity in prognostication. A recent emphasis on unifying themes has driven an increasingly standardized approach to NEN classification, as delineated in the World Health Organization's Classification of Tumours series. Here, we review recent developments in NEN classification, with a focus on NENs of the pancreas and lungs.

Neuroendocrine neoplasms of the lung and gastrointestinal system: convergent biology and a path to better therapies

Neuroendocrine neoplasms (NENs) can develop in almost any organ and span a spectrum from well-differentiated and indolent neuroendocrine tumours (NETs) to poorly differentiated and highly aggressive neuroendocrine carcinomas (NECs), including small-cell lung cancer (SCLC). These neoplasms are thought to primarily derive from neuroendocrine precursor cells located throughout the body and can also arise through neuroendocrine transdifferentiation of organ-specific epithelial cell types. Hence, NENs constitute a group of tumour types that share key genomic and phenotypic characteristics irrespective of their site of origin, albeit with some organ-specific differences. The establishment of representative preclinical models for several of these disease entities together with analyses of human tumour specimens has provided important insights into crucial aspects of their biology with therapeutic implications. In this Review, we provide a comprehensive overview of the current understanding of NENs of the gastrointestinal system and lung from clinical and biological perspectives. Research on NENs has typically been siloed by the tumour site of origin, and a cross-cutting view might enable advances in one area to accelerate research in others. Therefore, we aim to emphasize that a better understanding of the commonalities and differences of NENs arising in different organs might more effectively inform clinical research to define therapeutic targets and ultimately optimize patient care.

Bone marrow metastatic neuroendocrine carcinoma with unknown primary site: A case report and review of the literature

BACKGROUND

Metastatic neuroendocrine carcinoma (NEC) of bone marrow is uncommon. Here, we report a case of bone marrow metastatic NEC with an unknown primary site.

CASE SUMMARY

A 73-year-old Chinese woman was admitted to our hospital because marked chest distress and asthma lasting 1 d on March 18, 2018. She was initially diagnosed with pulmonary infection, cardiac insufficiency, thrombocytopenia and severe anemia. Following treatment with antibiotic therapy, diuresis and blood transfusion, the patient’s symptoms greatly improved. After bone marrow examinations, the patient was diagnosed with bone marrow metastatic NEC, bone marrow necrosis (BMN) and secondary myelofibrosis (MF). Further imaging workup did not show the primary tumor, we presumed that the primary site might regress spontaneously or merely be unexplored due to lack of positron emission tomography with gallium peptide. Everolimus (10 mg/d) was added to the treatment and the best supportive and symptomatic therapies were also administered. Unfortunately, the patient’s condition continued to deteriorate and she died on May 15, 2018.

CONCLUSION

Bone marrow invasion of NEC is rare and our patient who suffered from bone marrow metastatic NEC as well as secondary BMN and MF had an extremely poor prognosis. Bone marrow biopsy plays an important role in the diagnosis of solid tumors invading bone marrow.

Surgical Outcomes, Long-Term Survivals and Staging Systems of World Health Organization G3 Pancreatic Neuroendocrine Tumors

Background: In 2017, the World Health Organization (WHO) defined a new category of pancreatic neuroendocrine neoplasms named G3 pancreatic neuroendocrine tumors (p-NETs), whose surgical outcomes, long-term survivals and staging systems have not been well documented. Methods: Data from eligible patients with G3 p-NETs defined using the WHO 2017 grading classification at our institute were retrospectively analyzed. Results: Our study enrolled 80 patients with WHO G3 p-NETs, including 50 women and 30 men. The accumulative 5-year overall survival (OS) of G3 p-NETs was 29.7%. The current staging system by the American Joint Committee on Cancer (AJCC) failed to discriminate the survival difference between Stage II and Stage III (p = 0.172), while notable differences with regard to the OS were statistically offered between each stage using the modified tumor−node−metastasis (mTNM) staging system (all p < 0.05). The OS of patients receiving surgical resection was significantly better than those with palliative operation (p < 0.05). Both the current AJCC system and proposed mTNM system were independent predictors for the OS of G3 p-NETs (p = 0.017 and p = 0.032, respectively). The 95% confidence intervals of the proposed mTNM staging system were smaller than that of the current AJCC system (0.626−8.217 and 0.329−10.013, respectively), indicating a relatively more accurate predictive ability. Conclusion: Our demonstration revealed that surgical resection was an independent predictor for the favorable prognosis of patients with G3 p-NETs. Moreover, the new mTNM staging system was more suitable and practical than the current AJCC system for stratifying G3 p-NETs into prognostic groups.

Metastatic rectal neuroendocrine carcinoma presenting with treatment-refractory immune thrombocytopenia: A case report and literature review

RATIONALE

Colorectal neuroendocrine cancer (CRNEC) accounts for < 1% of all colorectal cancers. It presents in advanced stages and carries a risk of poor survival. CRNEC may be diagnosed incidentally on imaging or routine endoscopy. When symptomatic, it may mimic colorectal adenocarcinoma. Syncope and immune thrombocytopenic purpura (ITP) have not previously been reported as clinical presentations.

PATIENT CONCERNS

A 57-year-old man with human immunodeficiency virus infection on treatment, seizure and stroke without residue presented for the evaluation of fall and syncope.

DIAGNOSIS

Physical examination revealed tachycardia, swelling, and ecchymosis of his proximal left lower extremity. Laboratory tests showed a new isolated thrombocytopenia of 26,000/mm3. Computed tomography for a trauma survey showed an incidental left posterior rectal wall mass. After hospital admission, his platelet count dropped to 14,000/mm3. A peripheral blood smear revealed low platelet count, no schistocytes or immature cells. ITP at a high risk for bleeding was diagnosed and treated with standard medical therapy but remained refractory. Bone marrow biopsy showed metastatic neuroendocrine carcinoma, likely from the rectum.

INTERVENTIONS

Patient received courses of high-dose dexamethasone and intravenous immunoglobulin. He also receive eleven units of platelet transfusion. A course of rituximab was administered. The platelet count response was suboptimal or short lived with drop to a nadir of 4000/mm3. However, after initiation of Eltrombopag, the thrombocytopenia resolved. Patient was started on etoposide, carboplatin, Atezolizumab. His hospital stay was complicated by neutropenia and sepsis, which was successfully treated.

OUTCOMES

He was discharged to subacute rehab in stable condition. About 4 months later, he was readmitted for severe thrombocytopenia, septic shock, and acute respiratory failure. Despite appropriate treatment, the patient deteriorated and expired.

CONCLUSION

CRNEC is a rare aggressive disease with dismal outcome that lacks standardized treatment. Metastasis to the bone marrow is uncommon and concomitant ITP has not been reported. We report a rare case of rectal neuroendocrine carcinoma metastatic to bone marrow associated with refractory ITP and review the relevant literature.

Expanding Therapeutic Opportunities for Extrapulmonary Neuroendocrine Carcinoma

Poorly differentiated neuroendocrine carcinomas (PD-NEC) are rare cancers garnering interest as they become more commonly encountered in the clinic. This is due to improved diagnostic methods and the increasingly observed phenomenon of "NE lineage plasticity," whereby nonneuroendocrine (non-NE) epithelial cancers transition to aggressive NE phenotypes after targeted treatment. Effective treatment options for patients with PD-NEC are challenging for several reasons. This includes a lack of targetable, recurrent molecular drivers, a paucity of patient-relevant preclinical models to study biology and test novel therapeutics, and the absence of validated biomarkers to guide clinical management. Although advances have been made pertaining to molecular subtyping of small cell lung cancer (SCLC), a PD-NEC of lung origin, extrapulmonary (EP)-PD-NECs remain understudied. This review will address emerging SCLC-like, same-organ non-NE cancer-like and tumor-type-agnostic biological vulnerabilities of EP-PD-NECs, with the potential for therapeutic exploitation. The hypotheses surrounding the origin of these cancers and how "NE lineage plasticity" can be leveraged for therapeutic purposes are discussed. SCLC is herein proposed as a paradigm for supporting progress toward precision medicine in EP-PD-NECs. The aim of this review is to provide a thorough portrait of the current knowledge of EP-PD-NEC biology, with a view to informing new avenues for research and future therapeutic opportunities in these cancers of unmet need.

Review of Checkpoint Inhibitor Immunotherapy in Neuroendocrine Tumor of Prostate and Our Experience in 2 Cases

Neuroendocrine prostate cancer (NEPC) is a rare entity. De novo NEPC is extremely rare; other cases are usually adenocarcinoma previously treated with hormonal therapies transforming to NEPC. Most of the cases are metastatic at diagnosis and regardless of the histology types, the prognosis is poor. In this report, we reviewed the checkpoint inhibitor (CPI) immunotherapies used for neuroendocrine tumors of the prostate. Very limited data with only a few cases were published which showed a limited activity by immunotherapy; therefore, we present our experience of 2 cases: (1) adenocarcinoma with foci of NEPC and (2) adenocarcinoma transforming to NEPC after treatment with androgen deprivation therapy (ADT); both of which were initially managed with ADT, chemotherapy followed by immunotherapy with durvalumab, a programmed death ligand 1 inhibitor. In these 2 cases, CPI therapy showed limited efficacy, suggesting that neuroendocrine histology is not very responsive to CPI treatment, regardless if onset is early or late. Other therapies need to be explored for the treatment of NEPC.