Carcinoid tumours Accordion Q&A Notes
Carcinoid Tumours Active Recall Accordion Q&A Revision Notes
(Question and Answer Active Recall Accordion Notes – please click the arrow to display the answer to the revision questions)
Definition of Carcinoid Tumors
• Neuroendocrine tumors found in organs like the GI tract, lungs, and appendix
• Originate from neuroendocrine cells that produce hormones (e.g. serotonin) and bioactive substances
• Slow-growing but can be malignant
• Carcinoid Syndrome is caused by serotonin release from liver metastases
• Can occur in lung carcinoids when mediators bypass liver clearance
• Rare, slow-growing tumors in the neuroendocrine system
• Commonly found in gut-derived tissues
• May be asymptomatic but can turn malignant
• Common metastatic sites: liver, lymph nodes, ovaries, peritoneum, spleen
• Cause carcinoid syndrome with symptoms like bronchospasm, diarrhea, flushing, and heart lesions
• Lung carcinoids represent 1-2% of lung cancers, often in major bronchi, right lung, and middle lobe
Aetiology and Risk Factors of Carcinoid Tumors
• Unknown cause
• Associated with genetic syndromes: MEN1 (Multiple Endocrine Neoplasia type 1), NF1 (Neurofibromatosis type 1)
• Risk factors: Family history of neuroendocrine tumors, older age, exposure to tobacco smoke, and occupational hazards
Pathophysiology of Carcinoid Tumors
• Arise from neuroendocrine cells
• Produce excessive hormones and bioactive substances
• Driven by genetic and molecular changes
• Hormone production leads to symptoms and complications
Differential Diagnosis of Carcinoid Tumors
• Other Neuroendocrine Tumors
• Gastrointestinal Stromal Tumors (GIST)
• Lung Cancer
• Benign Lesions
• Flushing: Alcohol, nitrates, spicy foods, systemic mastocytosis, medullary thyroid cancer, menopause, renal cancer, hyperthyroidism
• Diarrhea: Gastroenteritis, inflammatory bowel disease
• Bronchospasm: Anaphylaxis, asthma, inhaled foreign body, COPD
Epidemiology of Carcinoid Tumors in the UK
• Low incidence: 2.7 per 100,000 population
• Carcinoid syndrome incidence: 0.27 per 100,000 (USA data)
• Common sites: Small intestine, rectum, colon, pancreas, appendix
• Typically affects individuals in their 40s to 60s but can occur at any age
• Most common neuroendocrine tumors (NETs)
• Second most common digestive cancer
• Up to 10% found incidentally in post-mortem exams
• Family history increases risk
Clinical Presentation of Carcinoid Tumors
• Symptoms vary by tumor location and hormone production
• Skin flushing (early sign)
• Diarrhea
• Breathing issues
• Abdominal pain
• Palpitations
• Weight loss
• Bronchospasm
• Hypotension
• Heart valve problems
• Hormone secretion (e.g. Cushing’s syndrome)
• Pellagra (rare)
• Abdominal mass
• Hepatomegaly
• Telangiectasia
• Affects heart valves causing dysfunction
• Gastric carcinoid: Pruritic flushing, peptic ulcers
• Bronchial carcinoid: Prolonged flushing, mental changes
• Pellagra and hypoalbuminemia due to tryptophan conversion
Investigations for Carcinoid Tumors
• Urinary 5-HIAA: Elevated levels suggest carcinoid syndrome; measures serotonin breakdown product
• Plasma Chromogranin A: Sensitive for screening but not specific
• 24-hour Urinary 5-HIAA: Over 25 mg/24 hours indicates carcinoid syndrome; can be influenced by diet and drugs
• Blood tests: FBC (Full Blood Count), LFTs (Liver Function Tests), TFTs (Thyroid Function Tests)
• Hormone levels: Parathyroid hormone, calcium, calcitonin, prolactin
• Tumor markers: Alpha-fetoprotein, CEA (Carcinoembryonic Antigen), beta-hCG
• When initial screening results are unclear; may induce a carcinoid crisis
Management of Carcinoid Tumors
• Management depends on the tumor type, size, spread, and symptoms
• Surgery: Primary treatment for localized tumors
• Endoscopic resection: Suitable for small, localized lesions
• Debulking surgery: For symptomatic metastases
• Symptomatic control: Somatostatin analogues such as octreotide to control hormone-related symptoms
• Somatostatin analogues (e.g., octreotide, lanreotide) to control hormone secretion
• Interferon-alpha: May be used in some cases to control tumor growth and symptoms
• Chemotherapy: For aggressive or poorly differentiated tumors, though generally less effective for well-differentiated carcinoid tumors
• Effective for controlling symptoms of carcinoid syndrome, such as flushing and diarrhea
• Used in patients with metastatic disease to reduce hormone production and slow tumor progression
• PRRT may be considered for patients with inoperable or metastatic neuroendocrine tumors that express somatostatin receptors
• Involves radiolabelled somatostatin analogues to deliver targeted radiation to the tumor
• Nutritional support for malabsorption or weight loss
• Treatment of carcinoid heart disease: Valvular surgery if significant cardiac symptoms develop
• Antidiarrheal agents to manage diarrhea if not controlled by somatostatin analogues
Prognosis of Carcinoid Tumors
• Depends on the location, size, extent of spread, and differentiation of the tumor
• Well-differentiated tumors generally have a better prognosis
• The presence of carcinoid syndrome may indicate a higher likelihood of metastasis and affect overall prognosis
• The prognosis for localized tumors is generally favorable with surgical removal
• Metastatic disease has a variable prognosis, depending on the response to treatment and the degree of hormone secretion control
Complications of Carcinoid Tumors
• Carcinoid syndrome, including symptoms like flushing, diarrhea, and wheezing
• Carcinoid heart disease: Leads to valvular heart lesions and right heart failure
• Intestinal obstruction due to tumor growth or fibrosis
• Nutritional deficiencies: Malabsorption due to extensive hormone secretion
• Carcinoid crisis: A potentially life-threatening condition characterized by severe flushing, hypotension, and bronchospasm, often triggered by anesthesia or surgery
Prevention and Monitoring of Carcinoid Tumors
• No specific prevention strategies due to the unclear cause
• Individuals with a family history of neuroendocrine tumors may benefit from genetic counseling and screening
• Regular follow-up with imaging and biochemical markers (e.g., Chromogranin A, urinary 5-HIAA) to detect recurrence or progression
• Frequency of monitoring depends on the stage of disease and treatment response
• Lifelong follow-up is recommended for patients with carcinoid tumors, especially for those with metastatic disease
• Monitoring helps to manage symptoms, detect tumor recurrence, and address any complications such as carcinoid heart disease