Neuroendocrine tumours (NETs) are a diverse group of cancers that arise from neuroendocrine cells, which are responsible for producing hormones and peptides. These tumours can occur in various parts of the body, including the respiratory system.
Respiratory symptoms in NET patients can significantly impact their quality of life, making it essential to understand their causes, diagnosis, and management.
This article explores the various aspects of respiratory symptoms in NET patients, providing a comprehensive overview for patients and healthcare providers alike.
Neuroendocrine Cancer Australia (NECA), is dedicated to assisting individuals with neuroendocrine cancer and their families. NECA offers a wealth of resources, educational programs, and advocacy efforts aimed at deepening the understanding of NETs, improving patient care, and encouraging research advancements. Patients diagnosed with NETs can engage with NECA’s comprehensive support and information by calling the NET nurse line.
Primary and metastatic NETs affecting the respiratory system
NETs can either originate in the respiratory system or metastasise to it from other primary sites.
These tumours can be classified into two segments based on their histological features and behaviour.
- Typical carcinoids are generally less aggressive
- Atypical carcinoids have a higher tendency to metastasise and recur
There are four types of NETs of the lungs:
- Typical carcinoid (TC)
- Atypical carcinoid (AC)
- Large cell NeuroEndocrine carcinoma (LCNEC)
- Small cell lung cancer (SCLC)
Metastatic NETs affecting the respiratory system occur when NETs from other primary sites, such as the gastrointestinal tract or pancreas, spread to the lungs or pleura. This spread can cause a range of respiratory symptoms, whether directly related to tumour involvement, or via secondary effects of the disease.
Causes of respiratory symptoms in NET patients
For patients, their families, and primary care teams, it’s important to understand the causes of respiratory symptoms in NET patients. These can range from physical involvement of tumours and metastasis, to hormonal secretion, to related syndromes.
Direct tumour involvement in the lungs
Direct involvement of NETs in the lungs can lead to various respiratory symptoms, such as:
- Cough
- Wheezing
- Shortness of breath
Additionally, large tumours can compress adjacent structures, causing pain and other related symptoms.
Hormonal secretion
NETs are known for their ability to secrete hormones and a variety of peptides (little proteins), which can have systemic effects. In the respiratory system, excessive hormone secretion can lead to bronchospasm and wheezing.
For example, serotonin, a common hormone secreted by NETs, can cause bronchoconstriction and contribute to respiratory symptoms.
Paraneoplastic syndromes
Paraneoplastic syndromes are conditions that arise from the indirect effects of tumours, often due to hormone or cytokine secretion. In NET patients, paraneoplastic syndromes can manifest as respiratory symptoms, including cough and shortness of breath.
These syndromes can complicate the clinical picture and make diagnosis and management more challenging.
Metastasis to the respiratory tract
Metastatic spread of NETs to the respiratory tract can cause a range of symptoms depending on the location and extent of metastasis. Metastases in the lungs can lead to:
- Persistent cough
- Dyspnea (difficulty breathing, shortness of breath)
- Haemoptysis (coughing up blood)
Pleural involvement can cause pleural effusion (build up of fluid between the layers of your pleura and lungs) and chest pain.
Common respiratory symptoms
. Understanding of the symptoms can aid in the often challenging clinical diagnoses of NETs and related conditions.
Persistent cough
A persistent cough is a common symptom in NET patients with respiratory involvement. This cough can be dry or productive and may vary in severity. It often results from tumour irritation of the bronchial tree or hormone-induced bronchospasm.
Shortness of breath (dyspnea)
Dyspnea, or shortness of breath, is another frequent symptom. It can be caused by airway obstruction, reduced lung capacity due to tumour growth, or hormone-related bronchoconstriction. Dyspnea can significantly affect a patient’s ability to perform daily activities and reduce their overall quality of life.
Wheezing
Wheezing is a high-pitched whistling sound produced during breathing, typically caused by narrowed or obstructed airways. In NET patients, wheezing can result from tumour-induced airway obstruction or hormonal effects on bronchial smooth muscle.
Haemoptysis (coughing up blood)
Haemoptysis, or coughing up blood, can be an alarming symptom for patients. It occurs when tumours erode into blood vessels within the lungs or bronchial tree. While the amount of blood can vary, any instance of hemoptysis warrants prompt medical evaluation.
Chest pain
Chest pain in NET patients can result from various causes, including direct tumour invasion, pleural involvement, or paraneoplastic syndromes. The pain may be sharp or dull, constant or intermittent, and can significantly impact a patient’s quality of life.
Diagnosis and evaluation
After a care team reaches a thorough understanding of the causes and symptoms of respiratory issues alongside NETs, the next stage is diagnosis and evaluation of the patient.
Clinical assessment and history
A thorough clinical assessment and detailed medical history are crucial for diagnosing respiratory symptoms in NET patients. Healthcare providers should inquire about the onset, duration, and severity of symptoms, as well as any associated factors such as smoking history or previous lung conditions.
Imaging studies (CT, MRI, PET Scans)
Imaging studies are essential for evaluating respiratory symptoms in NET patients.
- CT scans provide detailed images of the lungs and can help identify tumours, metastases, and other abnormalities.
- MRIÂ can be useful for assessing soft tissue involvement and providing detailed images of the chest structures.
- PET scans are valuable for detecting metabolically active tumours and metastases, aiding in the staging and management of NETs.
Pulmonary function tests
Pulmonary function tests (PFTs) measure lung capacity and airflow, helping to assess the impact of tumours on respiratory function. These tests can identify obstructive or restrictive lung disease patterns and guide treatment decisions.
Bronchoscopy and biopsy
Bronchoscopy involves inserting a flexible tube with a camera into the airways to visualise and biopsy tumours. This procedure allows for direct examination of the bronchial tree, collection of tissue samples for histopathological analysis, and sometimes, therapeutic interventions such as tumour debulking.
Management of respiratory symptoms
Respiratory symptoms related to NETs can fortunately be managed with a range of treatments and interventions. The exact mix of these will depend on the patient, the progression of the neuroendocrine tumour, and a range of other factors.
Medical treatments
Bronchodilators are medications that help open up the airways by relaxing bronchial smooth muscle. They are commonly used to relieve symptoms of wheezing and shortness of breath in NET patients with bronchospasm.
Hormone therapy aims to control the secretion of bioactive substances by NETs, thereby reducing hormone-related symptoms. Somatostatin analogs, such as octreotide and lanreotide can manage hormone secretion and alleviate symptoms like wheezing and flushing.
Various symptom-relieving medications can be prescribed to manage respiratory symptoms and improve quality of life. These may include:
- Cough suppressants: To reduce persistent coughing.
- Pain relievers: To manage chest pain associated with tumour growth or pleural involvement.
- Antibiotics: If there is a secondary infection contributing to respiratory symptoms.
Surgical interventions
Surgical resection of tumours is often considered for localised NETs in the lungs. Removing the tumour can alleviate symptoms, improve lung function, and potentially cure the disease if caught early.
For patients with advanced disease or those who are not candidates for surgery, palliative procedures can help relieve symptoms. These procedures may include bronchoscopic interventions to remove obstructing tumours or pleural drainage for effusions.
Radiation and chemotherapy
Targeted radiation therapy
Targeted radiation therapy, such as stereotactic body radiotherapy (SBRT), can be used to treat localised tumours in the lungs. This approach delivers high doses of radiation precisely to the tumour, minimising damage to surrounding healthy tissue.
Chemotherapeutic agents
Chemotherapy can be effective for controlling tumour growth and managing symptoms in NET patients with respiratory involvement. Agents can be used either alone or in combination, and can include:
- Temozolomide
- Capecitabine
- Carboplatin / Etoposide
Impact on quality of life
The impact of respiratory issues alongside NETs on a patient’s quality of life can be difficult, and will vary from patient to patient.
Physical and emotional impacts
The physical and emotional effects of respiratory symptoms in NET patients can be profound.
- Physically, these symptoms can limit mobility, reduce physical activity, and increase the risk of complications such as infections.
- Emotionally, chronic respiratory symptoms can lead to anxiety, depression, and social isolation, further impacting the patient’s overall well-being.
Fortunately, there are ways to manage the physical and emotional effects of the condition. Patient wellbeing is paramount, and it often takes the help of care teams and loved ones to make a patient feel comfortable.
Strategies for managing respiratory symptoms
Effective management of respiratory symptoms in NET patients requires a comprehensive approach that includes medical treatments, lifestyle modifications, and psychological support. Strategies for managing these symptoms include:
- Regular light exercise can promote proper lung function and overall physical health.
- Breathing exercises such as diaphragmatic breathing and pursed-lip breathing can improve ventilation and reduce dyspnea.
- Stress management techniques including mindfulness and relaxation exercises can help a patient cope with the emotional burden of chronic respiratory symptoms.
Support resources for patients
Access to support resources is crucial for both patients and caregivers. These resources can provide information, practical advice, and emotional support. Some valuable resources include:
- Patient advocacy groups including Neuroendocrine Cancer Australia are an incredible resource of support and information.
- Online communities where patients and caregivers can connect, share experiences, and offer mutual support.
- Healthcare teams: Comprising oncologists, pulmonary physician, dietitian, exercise physiologist, and mental health professionals who can provide comprehensive care and support.
Research and future directions
Research on the respiratory involvement of NETs is ongoing, with studies focusing on understanding the underlying mechanisms, improving diagnostic methods, and developing effective treatments. These studies aim to enhance the quality of life for NET patients by addressing the root causes of respiratory symptoms.
Emerging therapies and clinical trials hold promise for better managing respiratory symptoms in NET patients.
Understanding the complexities of respiratory symptoms in neuroendocrine cancer is essential for providing comprehensive care to patients.
Through a combination of medical treatments, surgical interventions, lifestyle modifications, and psychological support, patients can manage these debilitating symptoms and improve their overall quality of life.
Ongoing research and emerging therapies offer hope for even better management strategies in the future, helping NET patients lead fuller, more active lives.
Further information and support for people diagnosed with NETs is available by calling the NECAÂ NET nurse line.
