Long-term survival in paraneoplastic Lambert-Eaton myasthenic syndrome

Burden of disease in Lambert-Eaton myasthenic syndrome: taking the patient's perspective

BACKGROUND

Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune-mediated neuromuscular disorder leading to muscle weakness, autonomic dysregulation and hyporeflexia. Psychosocial well-being is affected. Previously, we assessed burden of disease for Myasthenia gravis (MG). Here, we aim to elucidate burden of disease by comparing health-related quality of life (HRQoL) of patients with LEMS to the general population (genP) as well as MG patients.

METHODS

A questionnaire-based survey included sociodemographic and clinical data along with standardized questionnaires, e.g. the Short Form Health (SF-36). HRQoL was evaluated through matched-pairs analyses. Participants from a general health survey served as control group.

RESULTS

46 LEMS patients matched by age and gender were compared to 92 controls from the genP and a matched cohort of 92 MG patients. LEMS participants showed lower levels of physical functioning (SF-36 mean 34.2 SD 28.6) compared to genP (mean 78.6 SD 21.1) and MG patients (mean 61.3 SD 31.8). LEMS patients showed lower mental health sub-scores compared to genP (SF-36 mean 62.7 SD 20.2, vs. 75.7 SD 15.1) and MG patients (SF-36 mean 62.7 SD 20.2, vs. 66.0 SD 18.). Depression, anxiety and fatigue were prevalent. Female gender, low income, lower activities of daily living, symptoms of depression, anxiety and fatigue were associated with a lower HRQoL in LEMS.

DISCUSSION

HRQoL is lower in patients with LEMS compared to genP and MG in a matched pair-analysis. The burden of LEMS includes economic and social aspects as well as emotional well-being. TRIAL REGISTRATION INFORMATION: drks.de: DRKS00024527, submitted: February 02, 2021, https://drks.de/search/en/trial/DRKS00024527 .

Molecular classification of small cell lung cancer subtypes: Characteristics, prognostic factors, and clinical translation

ABSTRACT

Small cell lung cancer (SCLC) is a highly malignant tumor with a very poor prognosis; therefore, more effective treatments are urgently needed for patients afflicted with the disease. In recent years, emerging molecular classifications based on key transcription factors of SCLC have provided more information on the tumor pathophysiology, metastasis, immune microenvironment, and acquired therapeutic resistance and reflected the intertumoral heterogeneity of the various SCLC phenotypes. Additionally, advances in genomics and single-cell sequencing analysis have further revealed the high intratumoral heterogeneity and plasticity of the disease. Herein, we review and summarize these recent lines of evidence and discuss the possible pathogenesis of SCLC.

Lambert-Eaton myasthenic syndrome

Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune disease characterized by proximal muscle weakness, loss of tendon reflexes, and autonomic dysfunction. Muscle weakness usually starts in the upper legs and can progress to oculobulbar and in severe cases respiratory muscles. P/Q-type voltage-gated calcium channels (VGCCs) localized in the presynaptic motor nerve terminal and in the autonomic nervous system are targeted by antibodies in LEMS patients. These antibodies can be detected in about 90% of patients, and the presence of decrement and increment upon repetitive nerve stimulation is also a highly sensitive diagnostic test. Rapid diagnosis is important because of the association with SCLC in 50%-60% of patients, which stresses the need for vigorous tumor screening after diagnosis. Clinical parameters can predict tumor probability and guide frequency of tumor screening. Treatment of the tumor as well as symptomatic treatment and immunosuppression can effectively control symptoms in the majority of patients.

Guideline for the management of myasthenic syndromes

Myasthenia gravis (MG), Lambert-Eaton myasthenic syndrome (LEMS), and congenital myasthenic syndromes (CMS) represent an etiologically heterogeneous group of (very) rare chronic diseases. MG and LEMS have an autoimmune-mediated etiology, while CMS are genetic disorders. A (strain dependent) muscle weakness due to neuromuscular transmission disorder is a common feature. Generalized MG requires increasingly differentiated therapeutic strategies that consider the enormous therapeutic developments of recent years. To include the newest therapy recommendations, a comprehensive update of the available German-language guideline 'Diagnostics and therapy of myasthenic syndromes' has been published by the German Neurological society with the aid of an interdisciplinary expert panel. This paper is an adapted translation of the updated and partly newly developed treatment guideline. It defines the rapid achievement of complete disease control in myasthenic patients as a central treatment goal. The use of standard therapies, as well as modern immunotherapeutics, is subject to a staged regimen that takes into account autoantibody status and disease activity. With the advent of modern, fast-acting immunomodulators, disease activity assessment has become pivotal and requires evaluation of the clinical course, including severity and required therapies. Applying MG-specific scores and classifications such as Myasthenia Gravis Activities of Daily Living, Quantitative Myasthenia Gravis, and Myasthenia Gravis Foundation of America allows differentiation between mild/moderate and (highly) active (including refractory) disease. Therapy decisions must consider age, thymic pathology, antibody status, and disease activity. Glucocorticosteroids and the classical immunosuppressants (primarily azathioprine) are the basic immunotherapeutics to treat mild/moderate to (highly) active generalized MG/young MG and ocular MG. Thymectomy is indicated as a treatment for thymoma-associated MG and generalized MG with acetylcholine receptor antibody (AChR-Ab)-positive status. In (highly) active generalized MG, complement inhibitors (currently eculizumab and ravulizumab) or neonatal Fc receptor modulators (currently efgartigimod) are recommended for AChR-Ab-positive status and rituximab for muscle-specific receptor tyrosine kinase (MuSK)-Ab-positive status. Specific treatment for myasthenic crises requires plasmapheresis, immunoadsorption, or IVIG. Specific aspects of ocular, juvenile, and congenital myasthenia are highlighted. The guideline will be further developed based on new study results for other immunomodulators and biomarkers that aid the accurate measurement of disease activity.

Spontaneous regression of small cell lung cancer associated with Lambert-Eaton Myasthenic Syndrome: Case report

Spontaneous regression (SR) of cancer is very rare, especially of small cell lung cancer (SCLC). Recently, an association of paraneoplastic neurological syndrome (PNS) has been reported as a cause of SR of cancer, and onconeural antibodies are a possible factor in the SR of cancer associated with PNS. We herein report the first case of SR of SCLC combined with anti-P/Q-type of voltage-gated calcium channel (VGCC) antibody-positive Lambert-Eaton myasthenic syndrome (LEMS), a subtype of PNS. This case report suggests that SCLC may be spontaneously reduced by an autoimmune response induced by VGCC antibodies associated with LEMS. Our finding may help elucidate the mechanisms that inhibit tumor growth and cause the regression of tumors.

Clonal redemption of B cells in cancer

Potentially self-reactive B cells constitute a large portion of the peripheral B cell repertoire in both mice and humans. Maintenance of autoreactive B cell populations could conceivably be detrimental to the host but their conservation throughout evolution suggests performance of a critical and beneficial immune function. We discuss herein how the process of clonal redemption may provide insight to preservation of an autoreactive B cell pool in the context of infection and autoimmunity. Clonal redemption refers to additional recombination or hypermutation events decreasing affinity for self-antigen, while increasing affinity for foreign antigens. We then review findings in murine models and human patients to consider whether clonal redemption may be able to provide tumor antigen-specific B cells and how this may or may not predispose patients to autoimmunity.

A rare case of concomitant Lambert-Eaton myasthenic syndrome and syndrome of inappropriate antidiuretic hormone secretion in a patient with small cell lung carcinoma

Small cell lung carcinoma (SCLC) is a neuroendocrine carcinoma with a poor prognosis and is a common cause of paraneoplastic syndromes. Paraneoplastic syndromes are characterized by neurological and endocrinological problems in patients with malignancy and are often associated with difficulty in induction of chemotherapy. Here we report the case of a patient with SCLC concomitant with two paraneoplastic syndromes, syndrome of inappropriate antidiuretic hormone secretion (SIADH) and Lambert-Eaton myasthenic syndrome (LEMS), who was treated with a platinum-doublet chemotherapy regimen. A 66-year-old male patient presented with a 1-month history of progressive proximal muscle weakness, ataxia gait and 5 kg of body weight loss. The laboratory tests revealed hyponatremia due to SIADH and the existence of antibodies against P/Q-type voltage-gated calcium channels. The nerve conduction study showed a low amplitude of compound muscle action potential (0.38 mv), a 34% decrement on 3-Hz stimulation, and a 1939% increment after maximum voluntary contraction in 10 seconds (7.75 mv). The endobronchial ultrasound transbronchial needle aspiration biopsy revealed the pathological findings of SCLC. A 2-cycle chemotherapy regimen of irinotecan plus cisplatin resulted in temporary tumor shrinkage that lasted 2 months, but the improvement of proximal muscle weakness and hyponatremia were maintained over the tumor re-progression period after chemotherapy. Although paraneoplastic syndromes accelerate the decrease in performance status, chemotherapy for SCLC may improve symptoms related to paraneoplastic syndromes and could be considered in similar cases.

Lambert-Eaton Myasthenic Syndrome and Botulism

PURPOSE OF REVIEW

This article reviews the pathophysiology, epidemiology, clinical features, diagnosis, and treatment of Lambert-Eaton myasthenic syndrome (LEMS) and botulism, presynaptic disorders of neuromuscular transmission in which rapid diagnosis improves long-term outcomes.

RECENT FINDINGS

Therapy for LEMS has seen significant advances in recent years due to the approval of amifampridine-based compounds. LEMS is likely still underdiagnosed, particularly when no underlying malignancy is identified. Clinicians must have a strong suspicion for LEMS in any patient presenting with proximal weakness and autonomic dysfunction. Botulism is another rare disorder of presynaptic neuromuscular transmission that is most commonly associated with improper storage or preservation of food products. Over the past 2 decades, wound botulism has been increasingly reported among users of black tar heroin. A high degree of clinical suspicion and electrodiagnostic studies can be beneficial in distinguishing botulism from other acute neurologic disorders, and early involvement of state and federal health authorities may assist in confirming the diagnosis and obtaining treatment. When botulism is suspected, electrodiagnostic studies can provide clinical evidence of disordered neuromuscular transmission in advance of serologic confirmation, and providers should not wait for confirmation of the diagnosis to initiate treatment.

SUMMARY

A targeted clinical history and a thorough neurologic examination with support from serologic and electrodiagnostic studies are key to early diagnosis of LEMS and botulism. Early diagnosis of both conditions creates opportunities for therapy and improves outcomes.

Evolving role of immunotherapy in small cell lung cancer

Small cell lung cancer (SCLC) is a highly lethal subtype of lung cancer with a particularly poor prognosis. For decades, the best available systemic therapy was platinum plus etoposide chemotherapy, which offered frequent but transient responses. Survival gains were finally realized with the addition of immune checkpoint inhibitors to first-line chemotherapy. The phase III IMpower 133 trial showed that the addition of atezolizumab to chemotherapy improved survival. The subsequent CASPIAN trial demonstrated a similar benefit with durvalumab. These results quickly established chemo-immunotherapy as the preferred initial treatment for advanced SCLC, but outcomes remain poor for most patients. Here, we review the current and evolving role of immunotherapy in SCLC and outline emerging strategies poised to further elevate the standard of care.

Targeting the epigenetic processes to enhance antitumor immunity in small cell lung cancer

Dysregulation of the epigenetic processes, such as DNA methylation, histone modifications, and modulation of chromatin states, drives aberrant transcription that promotes initiation and progression of small cell lung cancer (SCLC). Accumulating evidence has proven crucial roles of epigenetic machinery in modulating immune cell functions and antitumor immune response. Epigenetics-targeting drugs such as DNA methyltransferase inhibitors, histone deacetylase inhibitors, and histone methyltransferase inhibitors involved in preclinical and clinical trials may trigger antitumor immunity. Herein, we summarize the impact of epigenetic processes on tumor immunogenicity and antitumor immune cell functions in SCLC. Furthermore, we review current clinical trials of epigenetic therapy against SCLC and the mechanisms of epigenetic inhibitors to boost antitumor immunity. Eventually, we discuss the opportunities of developing therapeutic regimens combining epigenetic agents with immunotherapy for SCLC.

Nationwide survey of Lambert-Eaton myasthenic syndrome in Japan

Background

There was no nationwide epidemiological study of Lambert-Eaton myasthenic syndrome (LEMS) in Japan; therefore, we conducted a nationwide survey.

Methods

For the first survey, we sent survey sheets to randomly selected medical departments (n=7545) to obtain the number of LEMS who visited medical departments between 1 January 2017 and 31 December 2017. For the second survey, we sent survey sheets to the corresponding medical departments to obtain clinical information on LEMS.

Results

We received 2708 responses (recovery rate: 35.9%) to the first survey. We estimated the number of LEMS as 348 (95% CI 247 to 449). The prevalence was 2.7 (95% CI 1.9 to 3.5) in 1 000 000 population. As a result of the second survey, we obtained 30 case records of 16 men and 14 women. Fourteen patients (46.7%) had a tumour, and 10 out of 14 tumours were small-cell lung carcinoma (71.4%). There was a predominance of men in the LEMS with tumour (paraneoplastic LEMS, P-LEMS) (n=11, 78.6%) and women in the LEMS without tumour (a primary autoimmune form of LEMS, AI-LEMS) (n=11, 68.8%) (p=0.0136). The onset age (mean (SD)) for the P-LEMS was 67.1 (9.0), and that for AI-LEMS was 57.8 (11.2) years old (p=0.0103). The disease duration (median) for P-LEMS was 2 years, and for AI-LEMS was 7.5 years (p=0.0134).

Conclusions

The prevalence of LEMS in Japan is similar to that in other countries. There are predominances of men in P-LEMS and women in AI-LEMS.

Lambert-Eaton Myasthenic Syndrome in Lung Cancer

The aim is to study lung cancer with Lambert-Eaton myasthenic syndrome (LEMS) with clinical and electrical characteristics of physiology and prognosis. Fourteen LEMS patients with lung cancer were studied retrospectively. The data including demographics, clinical presentation, treatments, and prognosis from the medical records were analyzed. Lung cancer coexisting with LEMS is more common in men (10/14). The median age was 67.1 years. Eleven (78.6%) patients experienced gradual onset of disease. Most patients presented nervous system lesions prior to occult tumors. The most common symptoms reported were proximal muscle weakness (92.9%), decreased or absent tendon reflexes (50%), and autonomic dysfunction (71.4%). All the patients showed reduction in action potential amplitude after repetitive peripheral never stimulation at low frequency and increased amplitude at high frequency. LEMS usually occurs prior to lung cancer with complicated and various clinical manifestations in our centers. We should improve awareness and knowledge of such disease to shorten the diagnostic delay and lead to few misdiagnoses.

Signal pathways and precision therapy of small-cell lung cancer

Small-cell lung cancer (SCLC) encounters up 15% of all lung cancers, and is characterized by a high rate of proliferation, a tendency for early metastasis and generally poor prognosis. Most of the patients present with distant metastatic disease at the time of clinical diagnosis, and only one-third are eligible for potentially curative treatment. Recently, investigations into the genomic make-up of SCLC show extensive chromosomal rearrangements, high mutational burden and loss-of-function mutations of several tumor suppressor genes. Although the clinical development of new treatments for SCLC has been limited in recent years, a better understanding of oncogenic driver alterations has found potential novel targets that might be suitable for therapeutic approaches. Currently, there are six types of potential treatable signaling pathways in SCLC, including signaling pathways targeting the cell cycle and DNA repair, tumor development, cell metabolism, epigenetic regulation, tumor immunity and angiogenesis. At this point, however, there is still a lack of understanding of their role in SCLC tumor biology and the promotion of cancer growth. Importantly optimizing drug targets, improving drug pharmacology, and identifying potential biomarkers are the main focus and further efforts are required to recognize patients who benefit most from novel therapies in development. This review will focus on the current learning on the signaling pathways, the status of immunotherapy, and targeted therapy in SCLC.

Gastroesophageal reflux disease and paraneoplastic neurological syndrome associated with long-term survival in limited stage small-cell lung cancer

Introduction

Patients with small‐cell lung cancer (SCLC) have a very poor prognosis. However, a subset of SCLC achieves long‐term survival. The objective of this study was to investigate factors and pattern of long‐term survival in patients with limited‐stage small cell lung cancer (LS‐SCLC) who achieved a complete response (CR) after chemoradiotherapy.

Patient and Methods

This was a single‐center retrospective study. The analysis of hazard ratio (HR) and 95% confidence interval (CI) was performed using Cox proportional hazards model. For pattern analysis, the date of recurrence was used as the endpoint. The nominal categorical variables were analyzed by the χ² test. Survival was estimated using the Kaplan–Meier model, and the results were reported as the median and interquartile range.

Results

We identified 162 patients, median age was 64.7 (56.2–70.2) years, and 94 (58%) were females. Eighty‐one patients (50%) had recurrence during follow‐up. Gastroesophageal reflux disease (GERD) (HR, 0.65; 95% CI, 0.45–0.93; p = 0.016) and neurological paraneoplastic syndrome (PNS) (HR, 0.46; 95% CI, 0.29–0.72; p < 0.001) were independent factors associated with improved overall survival (OS). Patients with GERD had prolonged recurrence free survival (RFS) compared to patients without GERD (median, 29.1 months vs. 13.9 months, p < 0.001), whereas patients with neurological PNS had a reduced recurrence rate compared to those patients without neurological PNS (No. [%], 8 [20.5] vs. 73 [59.3], p < 0.001).

Conclusions

Patients with LS‐SCLC achieving a CR after chemoradiotherapy, GERD, and neurological PNS were associated with improved OS. GERD and neurological PNS were associated with longer RFS and lower recurrence rate, respectively.

Myasthenia Gravis and Lambert-Eaton Myasthenic Syndrome: New Developments in Diagnosis and Treatment

"Myasthenia Gravis is, like it or not, the neurologist's disease!" (Thomas Richards Johns II, MD Seminars in Neurology 1982). The most common disorders in clinical practice involving defective neuromuscular transmission are myasthenia gravis (MG) and Lambert-Eaton myasthenic syndrome (LEMS). The hallmark of weakness related to malfunction of the neuromuscular junction (NMJ) is variability in severity of symptoms from minute to minute and hour to hour. Fatigable weakness and fluctuation in symptoms are common in patients whether the etiology is autoimmune, paraneoplastic, genetic, or toxic. Autoimmune MG is the most common disorder of neuromuscular transmission affecting adults with an estimated prevalence of 1 in 10,000. While LEMS is comparatively rare, the unique clinical presentation, the association with cancer, and evolving treatment strategies require the neurologist to be familiar with its presentation, diagnosis, and management. In this paper we provide a summary of the meaningful recent clinical developments in the diagnosis and treatment of both MG and LEMS.

An immune-related lncRNA signature predicts prognosis and adjuvant chemotherapeutic response in patients with small-cell lung cancer

Background

Patients with small-cell lung cancer (SCLC) are burdened by limited treatment options and the disease’s dismal prognosis. Long non-coding RNAs (lncRNAs) are essential regulators of genetic alteration and are actively involved in tumor immunity. However, few studies have examined interactions between immune genes and lncRNAs in SCLC.

Methods

Immune-related lncRNA (irlncRNA) expression profiles and their clinical significance were explored. We enrolled 227 patients with SCLC, including 79 cases from GSE65002 and 148 cases from a validation cohort with corresponding qPCR data. The least absolute shrinkage and selection operator (LASSO) model was applied to identify prognostic irlncRNAs for an irlncRNA-based SCLC signature. We additionally investigated the potential mechanisms and immune landscape of the signature using bioinformatics methods.

Results

An irlncRNA signature including 8 irlncRNAs (ENOX1-AS1, AC005162, LINC00092, RPL34-AS1, AC104135, AC015971, AC126544, AP001189) was established for patients with SCLC in the training cohort. Low-risk patients were more likely to benefit from chemotherapy and achieve a favorable prognosis. The signature was also well-validated in the validation cohort and various clinical subgroups. Compared to other clinical parameters, the irlncRNA signature exhibited superior predictive performance for chemotherapy response and prognosis. The signature was as an independent prognostic factor in the training and validation cohorts. Interestingly, low-risk patients showed an activated immune phenotype.

Conclusion

We constructed the first irlncRNA-based signature for chemotherapy efficacy and outcome prediction. The irlncRNA signature is a reliable and robust prognostic classifier that could be useful for clinical management and determination of potential chemotherapy benefit for patients with SCLC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02357-1.

Neuromuscular junction disorders beyond myasthenia gravis

PURPOSE OF REVIEW

To give an overview of the recent data on three autoimmune neuromuscular junction disorders with the recent Food Drug Administration (FDA) approval of amifampridine [3,4-Diaminopyridine (3,4-DAP) and 3,4-diaminopyridine phosphate (3,4-DAPP) for the treatment of Lambert-Eaton myasthenic syndrome (LEMS).

RECENT FINDINGS

In LEMS, the most important recent development is the introduction of FDA approved amifampridine for the symptomatic treatment. Randomized controlled studies showed an extremely effective improvement with amifampridine with daily dose of ≤ 80 mg with minimal side reactions. The next important development is in the electrodiagnostic criteria. Now 10 s exercise and an incremental response ≥ 60% either after 10 s exercise or at the high-rate stimulation in the repetitive nerve stimulation test are recommended as the standard tests.In 2016, myasthenia-gravis Lambert-Eaton overlap syndrome (MLOS) was coined as new syndrome for patients with myasthenia gravis and LEMS combined symptoms in same patients.In Isaacs syndrome, voltage gated calcium channel antibody order is no longer recommended because of low specificity for immunotherapy responsive disorders. Instead, ' leucine-rich glioma-inactivated 1 (LGI1) and contactin-associated like-2 (CASPR2) autoantibody tests' are recommended.

SUMMARY

In LEMS, amifampridine (3,4 DAP and 3,4-DAPP) is approved by the FDA as an effective symptomatic treatment. MLOS is coined as new syndrome recently. In Isaacs syndrome, LGI1 and CASPR2 antibody tests are recommended.

Paraneoplastic neurological syndromes: a practical approach to diagnosis and management

Paraneoplastic neurological syndromes (PNS) are the immune-mediated effects of a remote cancer and are characterised by an autoantibody response against antigens expressed by the tumour. Classically, well-characterised 'onconeuronal' antibodies target intracellular antigens and hence cannot access their antigens across intact cell membranes. The pathogenic mediators are likely to be neuronal-specific T cells. There is a variable response to immunotherapies and the clinical syndrome helps to direct the search for a specific set of tumours. By contrast, many newly emerging autoantibodies with oncological associations target cell surface epitopes and can exert direct pathogenic effects on both the central and peripheral nervous systems. Patients with these cell-surface directed autoantibodies often clearly respond to immunotherapies. Overall, the clinical, serological and oncological features in an individual patient helps determine the clinical relevance of the syndrome and hence guide its management. We summarise current knowledge and a practical approach to the investigation, diagnosis, treatment and outcomes of patients with suspected PNS.

Beneficial autoimmunity improves cancer prognosis

Many tumour antigens that do not arise from cancer cell-specific mutations are targets of humoral and cellular immunity despite their expression on non-malignant cells. Thus, in addition to the expected ability to detect mutations and stress-associated shifts in the immunoproteome and immunopeptidome (the sum of MHC class I-bound peptides) unique to malignant cells, the immune system also recognizes antigens expressed in non-malignant cells, which can result in autoimmune reactions against non-malignant cells from the tissue of origin. These autoimmune manifestations include, among others, vitiligo, thyroiditis and paraneoplastic syndromes, concurrent with melanoma, thyroid cancer and non-small-cell lung cancer, respectively. Importantly, despite the undesirable effects of these symptoms, such events can have prognostic value and correlate with favourable disease outcomes, suggesting 'beneficial autoimmunity'. Similarly, the occurrence of dermal and endocrine autoimmune adverse events in patients receiving immune-checkpoint inhibitors can have a positive predictive value for therapeutic outcomes. Neoplasias derived from stem cells deemed 'not essential' for survival (such as melanocytes, thyroid cells and most cells in sex-specific organs) have a particularly good prognosis, perhaps because the host can tolerate autoimmune reactions that destroy tumour cells at some cost to non-malignant tissues. In this Perspective, we discuss examples of spontaneous as well as therapy-induced autoimmunity that correlate with favourable disease outcomes and make a strong case in favour of this 'beneficial autoimmunity' being important not only in patients with advanced-stage disease but also in cancer immunosurveillance.

Presynaptic Paraneoplastic Disorders of the Neuromuscular Junction: An Update

The neuromuscular junction (NMJ) is the target of a variety of immune-mediated disorders, usually classified as presynaptic and postsynaptic, according to the site of the antigenic target and consequently of the neuromuscular transmission alteration. Although less common than the classical autoimmune postsynaptic myasthenia gravis, presynaptic disorders are important to recognize due to the frequent association with cancer. Lambert Eaton myasthenic syndrome is due to a presynaptic failure to release acetylcholine, caused by antibodies to the presynaptic voltage-gated calcium channels. Acquired neuromyotonia is a condition characterized by nerve hyperexcitability often due to the presence of antibodies against proteins associated with voltage-gated potassium channels. This review will focus on the recent developments in the autoimmune presynaptic disorders of the NMJ.

Advances in Small-Cell Lung Cancer (SCLC) Translational Research

Over the past several years, we have witnessed a resurgence of interest in the biology and therapeutic vulnerabilities of small-cell lung cancer (SCLC). This has been driven in part through the development of a more extensive array of representative models of disease, including a diverse variety of genetically engineered mouse models and human tumor xenografts. Herein, we review recent progress in SCLC model development, and consider some of the particularly active avenues of translational research in SCLC, including interrogation of intratumoral heterogeneity, insights into the cell of origin and oncogenic drivers, mechanisms of chemoresistance, and new therapeutic opportunities including biomarker-directed targeted therapies and immunotherapies. Whereas SCLC remains a highly lethal disease, these new avenues of translational research, bringing together mechanism-based preclinical and clinical research, offer new hope for patients with SCLC.

Type 1 diabetes mellitus as a disease of the β-cell (do not blame the immune system?)

Type 1 diabetes mellitus is believed to result from destruction of the insulin-producing β-cells in pancreatic islets that is mediated by autoimmune mechanisms. The classic view is that autoreactive T cells mistakenly destroy healthy ('innocent') β-cells. We propose an alternative view in which the β-cell is the key contributor to the disease. By their nature and function, β-cells are prone to biosynthetic stress with limited measures for self-defence. β-Cell stress provokes an immune attack that has considerable negative effects on the source of a vital hormone. This view would explain why immunotherapy at best delays progression of type 1 diabetes mellitus and points to opportunities to use therapies that revitalize β-cells, in combination with immune intervention strategies, to reverse the disease. We present the case that dysfunction occurs in both the immune system and β-cells, which provokes further dysfunction, and present the evidence leading to the consensus that islet autoimmunity is an essential component in the pathogenesis of type 1 diabetes mellitus. Next, we build the case for the β-cell as the trigger of an autoimmune response, supported by analogies in cancer and antitumour immunity. Finally, we synthesize a model ('connecting the dots') in which both β-cell stress and islet autoimmunity can be harnessed as targets for intervention strategies.

First-line immune checkpoint inhibitors for extensive stage small-cell lung cancer: clinical developments and future directions

Small-cell lung cancer (SCLC) is an aggressive and rapidly growing disease with poor prognosis. Despite intense efforts to improve clinical outcomes, platinum/etoposide chemotherapy has remained the most effective regimen for first-line extensive disease SCLC for decades. The addition of immune checkpoint inhibitors, and specifically programmed death-ligand 1 inhibitors, to standard platinum/etoposide, significantly improves survival and represents a promising advance in this field. However, identification of a predictive biomarker to refine patient selection is an area of unmet need. Further understanding of tumour immunity and mechanism of resistance is required to design novel strategies that improve survival. In this review, we describe recent developments and future directions on first-line immune checkpoint blockade for extensive disease-SCLC.

Chemo-immunotherapy as first-line treatment for small-cell lung cancer

Small-cell lung cancer (SCLC) is a highly lethal subtype of lung cancer. Despite concerted efforts over the past several decades, there have been limited therapeutic advances. Traditional chemotherapy offers a high response rate and rapid symptomatic improvement, but its benefit is fleeting, and relapse is quick and unforgiving. Immunotherapy has delivered improved outcomes for patients with many cancers and there was compelling rationale for development in SCLC. While initial efforts with cytotoxic T-lymphocyte protein-4 inhibitors failed to improve upon chemotherapy alone, the addition of programmed death ligand-1 (PD-L1) inhibitors to first-line chemotherapy finally provided long-awaited gains in survival. Atezolizumab, when added to carboplatin and etoposide, improved both progression-free survival and overall survival. Durvalumab, when added to platinum plus etoposide, similarly improved OS. Biomarker development has stalled as PD-L1 expression and tumor mutational burden have not been useful predictive biomarkers. However, based on the significant survival improvements, both atezolizumab and durvalumab were approved by the US Food and Drug Administration to be given with first-line chemotherapy, and these regimens represent the new standards of care for SCLC.

Harnessing the Immune System to Tackle Small Cell Lung Cancer

Immunotherapy has improved first-line therapy for small cell lung cancer and has activity in the relapsed setting as well. The immunobiology of small cell lung cancer poses challenges for immunotherapy, and efforts are underway to unlock to the potential of immunotherapy through the identification of meaningful disease subsets and the development of novel combination therapies.

Update in the Management of Myasthenia Gravis and Lambert-Eaton Myasthenic Syndrome

Myasthenia gravis (MG) and Lambert-Eaton myasthenic syndrome (LEMS) are the most common disorders of neuromuscular transmission in clinical practice. Disorders of the neuromuscular junction (NMJ) are characterized by fluctuating and fatigable weakness and include autoimmune, toxic, and genetic conditions. Adults with NMJ disorders are most often antibody mediated, with MG being the most common, having a prevalence of approximately 1 in 10,000, and with women being affected about twice as often as men. This article focuses on advances in management of autoimmune MG and LEMS.

[Immune Characteristics of Small Cell Lung Cancer]

小细胞肺癌（small cell lung cancer, SCLC）是预后极差的一类肿瘤，30年来药物治疗无显著进展，免疫检查点抑制剂（immune checkpoint inhibitor, ICI）成为近年唯一突破：程序性死亡-1（programmed death-1, PD-1）抑制剂单药或联合细胞毒T淋巴细胞抗原-4（cytotoxic T-lymphocyte antigen-4, CTLA-4）抑制剂后线治疗SCLC的有效率为10%-33%，有效时间较持久；程序性死亡配体-1（programmed death ligand-1, PD-L1）抑制剂联合化疗对比传统化疗一线治疗广泛期SCLC（extensive stage-SCLC, ES-SCLC）的总生存期延长。尽管取得一定疗效，相对于非小细胞肺癌（non-small cell lung cancer, NSCLC）等对免疫治疗敏感的肿瘤类型，SCLC的疗效仍不令人满意，这可能与其免疫抑制特征有关。本综述对SCLC免疫特征的研究现状进行总结，包括淋巴细胞和免疫抑制细胞在肿瘤内浸润情况、PD-L1和主要组织相容复合物（major histocompatibility complex, MHC）在肿瘤的表达以及外周血免疫细胞的改变，并对这些免疫特征的预后及其对ICI疗效的预测价值进行分析。

[Immunotherapy Advances in Small Cell Lung Cancer]

Small cell lung cancer (SCLC) is a "refractory cancer" characterized by rapid growth and extensive early metastasis. About 70% of patients are already in the extensive stage at the time of diagnosis. Despite the high response rate to platinum-contained first-line chemotherapy, almost all patients subsequently experienced inevitable recurrence and had poor response to second-line treatment. The high mutation load and immunogenicity of SCLC suggest that immunotherapy may be effective for SCLC patients. Over the past few years, several clinical trials have evaluated the efficacy of checkpoint inhibitors [mainly cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and programmed death 1 (PD-1)/programmed death ligand-1 (PD-L1) inhibitors] in SCLC patients and demonstrated promising survival prospects. This article reviewed the clinical studies of immune checkpoint inhibitors (ICIs) in the first-line, maintenance and second or more line treatment of SCLC. Besides, predictive biomarkers were discussed to select suitable patients for immunotherapy effectively.

Lambert-Eaton Myasthenic Syndrome, Botulism, and Immune Checkpoint Inhibitor-Related Myasthenia Gravis

PURPOSE OF REVIEW

This article reviews the pathophysiology, epidemiology, clinical presentation, diagnosis, and treatment of Lambert-Eaton myasthenic syndrome (LEMS) and of botulism, and immune-related myasthenia gravis (MG) occurring in the context of immune checkpoint inhibitor therapy for cancer.

RECENT FINDINGS

The suspicion that LEMS is rare but also likely underdiagnosed is supported by recent epidemiologic data. A validated, LEMS-specific scale now exists to assess and monitor disease, and symptomatic and immunomodulatory treatments are available. As presynaptic disorders of neuromuscular transmission, LEMS and botulism share electrodiagnostic abnormalities but have important distinguishing features. Knowledge of the clinical features of botulism is needed, particularly with continued cases of infant botulism, the opioid epidemic increasing the incidence of wound botulism, and medical use of botulinum toxin, which may cause iatrogenic botulism. Foodborne botulism remains rare. Prompt recognition of botulism and administration of antitoxin can improve outcomes. MG may be exacerbated or may present de novo in the context of immune activation from immune checkpoint inhibitor therapies for cancer. Immune-related MG commonly overlaps with myositis and myocarditis. Corticosteroids typically result in improvement. However, immune-related MG can be more fulminant than its idiopathic counterpart and may cause permanent disability or death.

SUMMARY

The diagnosis of LEMS, botulism, or immune-related MG can generally be made from the patient's history, supplemented with directed questions, a physical examination designed to demonstrate abnormalities, and laboratory and electrodiagnostic testing. Early diagnosis and carefully selected treatment not only improve outcomes of the neuromuscular disease but can affect the prognosis of underlying malignancy, when present.

Lowering the cutoff value for increment increases the sensitivity for the diagnosis of Lambert-Eaton myasthenic syndrome

Background

Increment of compound muscle action potential amplitude is a diagnostic hallmark of Lambert‐Eaton myasthenic syndrome (LEMS). Making a diagnosis can be challenging, therefore, a proper cutoff for abnormal increment is highly relevant for improved recognition of this rare disease.

Methods

We determined the sensitivity and specificity of 60% and 100% cutoff values in all consecutive patients who underwent increment testing in our hospital from 1999 to 2016.

Results

We included 156 patients, 63 with LEMS and 93 without LEMS. Sensitivity of a 60% cutoff for increment testing was 77.8% (95% confidence interval 65.5%–87.3%) and 58.7% (45.6%–71.0%) for 100%. Specificity was 98.9% (94.2%–100%) and 100% (96.1%–100%) using a threshold of 60% and 100%, respectively.

Conclusions

Lowering the cutoff value for abnormal increment to 60% greatly increases sensitivity to diagnose LEMS without an overt loss in specificity.

[Research Progress of Immunotherapy and Prognostic Markers in Small Cell Lung Cancer]

近年来，虽然非小细胞肺癌患者的治疗效果得到了明显的改善，但小细胞肺癌（small cell lung cancer, SCLC）患者仍因治疗选择有限而预后很差。SCLC发病率占肺癌总体发病率的15%，具有恶性程度高、生长迅速、易发生远处转移及复发的特点，治疗十分棘手。随着免疫治疗获批于非小细胞肺癌等多种实体瘤，作为免疫源性相对较强的癌种，SCLC的相关临床研究也在开展中，并已取得一定的进展。另一方面，由于肿瘤异质性的存在，探索能够预测SCLC疗效的相关标志物对患者精准治疗至关重要。本综述阐述了目前SCLC免疫治疗及与SCLC免疫治疗相关生物标志物研究的最新进展。

Neuronal antibody detection and improved lung cancer prediction in Lambert-Eaton myasthenic syndrome

Since approximately 50% of patients with Lambert-Eaton myasthenic syndrome (LEMS) subsequently develop small-cell lung cancer (SCLC), it is important to be able to predict cancer occurrence in these patients at neurological presentation. We aimed to determine whether circulating biomarkers were effective and objective predictors of cancer development in LEMS. We found that the presence of either SOX2, N-type voltage gated calcium channel or GABAb antibodies at LEMS diagnosis was highly sensitive (84%) and specific (87%) for the detection of SCLC. Screening for SOX2 and neuronal antibodies is a useful adjunct to clinical predictive scoring tools in predicting SCLC in LEMS.

Long-term follow-up, quality of life, and survival of patients with Lambert-Eaton myasthenic syndrome

Objective

To study survival and to characterize long-term functional impairments and health-related quality of life (HRQOL) of patients with Lambert-Eaton myasthenic syndrome (LEMS).

Methods

In this observational study, survival of patients with LEMS, separately for nontumor (NT) and small cell lung cancer (SCLC), was compared to that of the Dutch general population and patients with SCLC. Disease course in patients with LEMS was recorded retrospectively. Several scales for functional impairments and health-related quality of life were assessed.

Results

We included 150 patients with LEMS. Survival was similar to that of the general population in 65 patients with NT-LEMS. Tumor survival was significantly longer in 81 patients with SCLC-LEMS compared to patients with non-LEMS SCLC (overall median survival 17 vs 7.0 months, p < 0.0001). At diagnosis, 39 (62%) of 63 patients with complete follow-up data were independent for activities of daily living, improving to 85% at the 1-year follow-up. The physical HRQOL composite score (55.9) was significantly lower than in the general population (76.3, p < 0.0001) and comparable to that of patients with myasthenia gravis (60.5). The mental HRQOL composite score was 71.8 in patients with LEMS, comparable to that of the general population (77.9, p = 0.19) and patients with myasthenia gravis (70.3).

Conclusions

This study shows that patients with NT-LEMS have normal survival. Patients with SCLC-LEMS have an improved tumor survival, even after correction for tumor stage. A majority of patients with LEMS report a stable disease course and remain or become independent for self-care after treatment.

Amifampridine for the treatment of Lambert-Eaton myasthenic syndrome

Introduction: The present status of amifampridine (AFP) for the treatment of Lambert-Eaton myasthenic syndrome (LEMS) is reviewed. Areas covered: All relevant literature identified through a PubMed search under treatment of LEMS, aminopyridine, and amifampridine are reviewed. An expert opinion on AFP was formulated. Expert opinion: AFPs, 3,4-DAP and 3,4-DAPP, are the most studied drugs in neuromuscular diseases. Randomized and non-randomized studies showed the most effective drug as symptomatic medication for LEMS. AFPs are safe and tolerable. Thus, AFPs should be the drug of choice for the symptomatic treatment in LEMS. As long as the daily dose is less than 80 mg a day, there is no concern for the serious side-reaction, seizure. Because of short-acting drug effects, it should be given three or four times a day. Peri-oral and finger paresthesia, the most common side-reaction, is accepted as a sign of drug-intake by many patients. Gastro-intestinal side reactions, the next common side-reaction of AFPs, are tolerable. AFPs are also the drug of choice and life-saving for LEMS crisis. For the long-term usage, it is proven to be safe and AFPs can be supplemented with liberal amount of pyridostigmine to sustain a symptomatic improvement without any undue side-reaction.

Lambert-Eaton Myasthenic Syndrome

Lambert-Eaton myasthenic syndrome is a paraneoplastic or primary autoimmune neuromuscular junction disorder characterized by proximal weakness, autonomic dysfunction and ariflexia. The characteristic symptoms are thought to be caused by antibodies generated against the P/Q-type voltage-gated calcium channels present on presynaptic nerve terminals and by diminished release of acetylcholine. More than half of Lambert-Eaton myasthenic syndrome cases are associated with small cell lung carcinoma. Diagnosis is confirmed by serologic testing and electrophysiologic studies. 3,4-diaminopyridine is effective symptomatic treatment of LEMS.

Recent Advances and Therapeutic Options in Lambert-Eaton Myasthenic Syndrome

Lambert-Eaton Myasthenic Syndrome (LEMS) is an autoimmune-mediated neurological disorder that manifests as muscle fatigue, diminished tendon reflexes, with symptoms of cholinergic overactivity. It can be associated with certain neoplastic conditions, the most common being small cell lung carcinoma (SCLC). The basic pathophysiology involved is antibody-mediated targeting of voltage-gated calcium channels (VGCC), which decreases the release of acetylcholine in the synaptic junction. Multiple treatment options have been introduced in the past and, recently, a new drug, amifampridine, has been approved by the Food and Drug Administration (FDA) for the treatment of weakness associated with these patients. We summarize this newly introduced drug with a brief description of other treatment options available.

Immunotherapy in small-cell lung cancer: from molecular promises to clinical challenges

Management of small cell lung cancer (SCLC) has not changed over the last decades. In more recent years, alterations of DNA repair machinery and other molecular pathways have been identified in SCLC and preclinical data suggest that dysregulation of these pathways might offer new therapeutic opportunities.

While immune checkpoint inhibitors (ICIs) have had a major impact on the clinical outcome of several solid tumors, including non-small cell lung cancer, the potential role of ICIs is currently under investigation in SCLC and some promising data are available. However, several clinical and biological hurdles have to be overcome and predictive markers are still eagerly needed. Knowledge of molecular pathways specifically involved in SCLC growth and treatment resistance is essential for a more rational planning of new combinations including ICIs.

The present manuscript summarizes the current clinical evidence on immunotherapy in SCLC, describes the molecular bases underlying treatment resistance and discusses the potentialities and the rationale of different therapeutic combinations.

A rare case of long-term paraesthesia diagnosed as a paraneoplastic syndrome by anti-SOX1 antibody determination

Paraneoplastic syndromes (PS) are a rare presentation of cancer, most commonly associated with small cell lung cancer (SCLC), breast cancer and haematologic malignancies. The diagnosis of PS is challenging because it could affect multiple organ systems and it may present before the tumour is visible by imaging. We report a malignant tumour diagnosed in a male patient who referred long-term paraesthesia and proximal muscle strength loss. After ruling out common causes of polyneuropathy, the anti-SOX1 antibody gave light to the diagnosis. A pulmonary opacity in the upper right lobe was observed in the chest X-ray and a pulmonary tumour was later confirmed by CT scan. The biopsy of the cervical lymphadenopathy determined an SCLC, which caused a PS called Lambert-Eaton myasthenic syndrome (LEMS). Our case raises awareness of a rare PS presentation, which can be diagnosed by specific antibodies, allowing early diagnosis and treatment of lung cancer.

Improved Prognosis and Increased Tumor-Infiltrating Lymphocytes in Patients Who Have SCLC With Neurologic Paraneoplastic Syndromes

BACKGROUND

Approximately 10% of patients with SCLC develop a paraneoplastic syndrome (PNS). Neurologic PNS are thought to improve prognosis, which we hypothesized is related to increased tumor-infiltrating lymphocytes and immune recognition.

METHODS

We queried 2,512,042 medical records from a single institution to identify patients who have SCLC with and without PNS and performed manual, retrospective chart review. We then performed multiplexed fluorescence immunohistochemistry and automated quantitative analysis (AQUA Technology) on tumors to assess CD3, CD4, and CD8 T cell infiltrates and programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) interactions. T cell infiltrates and PD-1/PD-L1 interaction scores were compared among patients with neurologic PNS, endocrinologic PNS, and a control group without PNS. Clinical outcomes were analyzed using the Kaplan-Meier method and Cox proportional hazards models.

RESULTS

We evaluated 145 SCLC patients: 55 with PNS (25 neurologic and 30 endocrinologic) and 90 controls. Patients with neurologic PNS experienced improved overall survival compared to patients with endocrinologic PNS and controls (median overall survival of 24 months versus 12 months versus 13 months, respectively). Of the 145 patients, we identified tumor tissue from 34 patients that was adequate for AQUA analysis. Among 37 specimens from these 34 patients, patients with neurologic PNS had increased T cell infiltrates (p = 0.033) and PD-1/PD-L1 interaction (p = 0.014) compared to tumors from patients with endocrinologic PNS or controls.

CONCLUSIONS

Tumor tissue from patients with SCLC with neurologic PNS showed increased tumor-infiltrating lymphocytes and PD-1/PD-L1 interaction consistent with an inflamed tumor microenvironment.

Lambert-Eaton Myasthenic syndrome: early diagnosis is key

Lambert-Eaton myasthenic syndrome (LEMS) is an uncommon disorder of neuromuscular transmission with distinctive pathophysiological, clinical, electrophysiological and laboratory features. There are two forms of LEMS. The paraneoplastic (P-LEMS) form is associated with a malignant tumor that is most frequently a small cell lung carcinoma (SCLC), and the autoimmune (A-LEMS) form is often related to other dysimmune diseases. Approximately 90% of LEMS patients present antibodies against presynaptic membrane P/Q-type voltage-gated calcium channels (VGCC). These antibodies are directly implicated in the pathophysiology of the disorder, provoke reduced acetylcholine (ACh) at the nerve terminal and consequently lead to muscle weakness. LEMS is clinically characterized by proximal muscle weakness, autonomic dysfunction and areflexia. In clinically suspected cases, diagnoses are confirmed by serological and electrodiagnostic tests. The detection of P/Q-type VGCC antibodies is supportive when there is clinical suspicion but should be carefully interpreted in the absence of characteristic clinical or electrodiagnostic features. Typical electrodiagnostic findings (ie, reduced compound motor action potentials (CMAPs), significant decrements in the responses to low frequency stimulation and incremental responses after brief exercise or high-frequency stimulation) reflect the existence of a presynaptic transmission defect and are key confirmatory criteria. Diagnosis requires a high level of awareness and necessitates the initiation of a prompt screening and surveillance process to detect and treat malignant tumors. In clinically affected patients without cancer and after cancer treatment, symptomatic treatment with 3,4-diaminopyridine or immunosuppressive agents can significantly improve neurologic symptoms and the quality of life. We present a detailed review of LEMS with special emphasis on the pathophysiological mechanisms, clinical manifestation and diagnostic procedure.

Clinical characteristics and long term follow-up of Lambert-Eaton myasthenia syndrome in patients with and without small cell lung cancer

In order to describe the clinical characteristics, treatment response and long-term follow up in Lambert-Eaton myasthenic syndrome (LEMS) patients with and without small cell lung cancer (SCLC) in East China, patients seen in Huashan Hospital from January 1997 to December 2017 were included. Clinical information was collected retrospectively and quantitative MG (QMG) score, manual muscle testing (MMT), activities of daily living (ADL) scale were evaluated when the patients were followed up. Of 50 patients, 23 (46%) were SCLC-LEMS and 20 (40%) were nontumor LEMS (NT-LEMS). The median onset age was 55.5 (18-86) years old and the gender ratio was about 1.8:1. It took less time to make the diagnosis (median time: 6 vs 22.5 months, p = 0.0003) and there were more patients with other paraneoplastic syndromes in SCLC-LEMS group than in NT-LEMS group (8/23 vs 0/20, p = 0.0042). Electrophysiologically, the peroneal compound motor action potential (CMAP) of rest showed difference between SCLC-LEMS and NT-LEMS (0.8 vs 1.6 mV, p = 0.0499). The median survival time of 19 SCLC-LEMS patients since the diagnosis of SCLC was 30 months. According to their survival time, SCLC patients with LEMS showed a more favorable prognosis than those without LEMS. In the time of follow-up, most NT-LEMS showed improvement or obtained status of CSR/PR/MM after immunosuppressive therapy and no significant difference in proportion of achieving CSR/PR/MM was found between SCLC-LEMS and NT-LEMS patients (0/5 vs 6/13, p = 0.114).

Immune Cell Infiltration May Be a Key Determinant of Long-Term Survival in Small Cell Lung Cancer

INTRODUCTION

Although most patients with SCLC die within a few months of diagnosis, a subgroup of patients survive for many years. Factors determining long-term survivorship remain largely unknown. We present the first comprehensive comparative genomic and tumor microenvironment analyses of SCLC between patients with long-term survivorship and patients with the expected survivorship.

METHODS

We compared surgically resected tumors of 23 long-term SCLC survivors (survival >4 years) and 18 SCLC survivors with the expected survival time (survival ≤2 years). There were no significant differences in clinical variables, including TNM staging and curative- versus non-curative-intent surgery between the groups. Gene expression profiling was performed by using microarrays, and tumor microenvironment analyses were performed by immunohistochemistry of prominent immune-related markers.

RESULTS

Immune-related genes and pathways represented the majority of the differentially overexpressed genes in long-term survivorship compared with in expected survivorship. The differences in the immunological tumor microenvironment were confirmed by quantitative immunostaining. Increased numbers of tumor-infiltrating and associated lymphocytes were present throughout tumors of long-term survivors of SCLC. Several differentiating patterns of enhanced antitumor immunity were identified. Although some areas of the tumors of long-term survivors of SCLC also harbored higher numbers of suppressive immune cells (monocytes, regulatory lymphocytes, and macrophages), the ratios of these suppressive cells to CD3-positive lymphocytes were generally lower in the tumors of long-term survivors of SCLC, indicating a less tumor-suppressive microenvironment.

CONCLUSIONS

Our data demonstrate that long-term survivorship of patients with SCLC is strongly influenced by the presence of the immune cells in the tumor microenvironment. Characterization of the antitumor immune responses may identify opportunities for individualized immunotherapies for SCLC.

Paraneoplastic autoimmunity and small-cell lung cancer: Neurological and serological accompaniments

Paraneoplastic neurological autoimmunity is often associated with small‐cell lung cancer (SCLC), a highly malignant neuroendocrine tumor. Paraneoplastic autoimmunity often correlates with longer survival. We describe the paraneoplastic neurological manifestations of patients with SCLC with and without SCLC‐predictive autoantibodies and the correlation between autoimmunity and survival. We reviewed the records of 116 patients (51% male) from the Mayo Clinic with histopathologically confirmed SCLC for whom stored serum was available for neural autoantibody testing. Cancer was limited stage in 41%; the median age at diagnosis was 64 years. Paraneoplastic neurological manifestations were recorded in 61% (decreasing frequency: peripheral neuropathy, dysautonomia, cognitive decline, cerebellar ataxia, neuromuscular junction disorder, seizures, cranial neuropathy, movement disorder, brainstem disorder, or myelopathy). Neural autoantibodies, some with pathogenic potential, were detected in the sera of SCLC patients with and without neurological autoimmunity. The most frequent among patients with neurological manifestations were: anti‐neuronal nuclear antibody‐type 1, voltage‐gated calcium channel (VGCC)‐N‐type, VGCC‐P/Q‐type, glutamic acid decarboxylase 65 (GAD65), SOX1, and muscle acetylcholine receptor (AChR); while the most common in patients without neurological manifestations were: GAD65, muscle‐AChR, and VGCC‐P/Q‐type. Neither cancer stage at diagnosis nor survival correlated with neurological manifestations or autoantibody‐positivity, except for shorter survival in patients with myelopathy. The only predictor of longer survival was limited‐stage disease at diagnosis.

Calcium channel autoimmunity: Cerebellar ataxia and lambert-eaton syndrome coexisting

INTRODUCTION

Neuronal calcium channel antibodies are a biomarker of Lambert-Eaton syndrome (LES) and cerebellar ataxia. We have encountered several patients with LES and cerebellar ataxia coexisting, and we sought to further define this association.

METHODS

We reviewed records of patients at our institution with a diagnosis of "Lambert-Eaton syndrome" and "cerebellar ataxia."

RESULTS

Seventeen patients were identified with LES and ataxia. Presenting symptoms were weakness (8), concurrent weakness and ataxia (4), ataxia (4), and other (1). Nine patients had small-cell lung carcinoma, 3 of whom had survival greater than 100 months. Immunotherapy responses were best among patients without cancer. Nine of 17 (53%) patients were alive at last follow-up (median survival 62 months; range, 8-240).

DISCUSSION

Calcium channel autoimmunity should be considered in patients with coexisting cerebellar ataxia and myasthenic weakness. Affected patients may survive small-cell carcinoma or have immunotherapy-responsive neurological symptoms. Muscle Nerve, 2018.