Neuroendocrine tumours (NETs) represent a spectrum of neoplastic diseases that arise from neuroendocrine cells, which are spread throughout various organ systems in the body. NETs are capable of producing peptides that can cause unique clinical syndromes; however, most are clinically silent until late presentation with mass effects or metastatic disease. Historically considered rare, NETs have now emerged as the fastest-growing class of cancers worldwide, accounting for about 2% of all cancer diagnoses.
In Canada, the incidence of NETs has mirrored this global trend, with approximately 12,000 to 15,000 Canadians currently living with this condition. Despite growing awareness, the complexity of NETs poses significant challenges in terms of diagnosis and treatment. Alarmingly, only 10% of Canadian patients with NETs have a complete and accurate diagnosis, which is essential for effective management and improved survival outcomes.
Epidemiology and Incidence
The most commonly diagnosed NETs are those found in the lungs, gastrointestinal tract, and pancreas. The reasons behind the increasing incidence of NETs are not entirely clear but may be attributed to improved diagnostic techniques, greater awareness among health professionals, and a true increase in occurrence.
NETs originate from the diffuse neuroendocrine system, which consists of cells that have both nerve and endocrine features. These cells can secrete a variety of hormones and biogenic amines, which, in excess, can lead to a range of symptoms such as flushing, diarrhea, and heart palpitations, characterizing the carcinoid syndrome commonly associated with these tumours.
Patients with NETs often have a protracted course before diagnosis, largely due to the non-specific nature of their symptoms. The most common NETs—those in the lungs, gastrointestinal tract, and pancreas—can present with symptoms related to hormone hypersecretion or, more commonly, symptoms resulting from tumour growth and metastasis, such as abdominal pain, bowel obstruction, or cough and hemoptysis in the case of lung NETs.
The diagnosis of NETs involves a combination of clinical assessment, biochemical testing for hormone markers, imaging studies, and histological confirmation. One of the primary markers used in the diagnosis and management of NETs is chromogranin A, a protein found inside neuroendocrine cells. However, the non-specific nature of symptoms and the variable secretion of hormones can delay diagnosis, resulting in a significant number of patients presenting with metastatic disease at the time of diagnosis.
Treatment of NETs is multifaceted and depends on the tumour’s location, stage, functional status, and the patient’s overall condition. Surgery remains the cornerstone of treatment for localized disease, while advanced cases may require a combination of therapies, including somatostatin analogues, targeted therapy, chemotherapy, and peptide receptor radionuclide therapy (PRRT).
In Canada, the approach to NETs is consistent with global practices but is tailored to the national healthcare system and resources. Canadian specialists are at the forefront of research in NETs, contributing to a growing body of knowledge that aims to improve patient outcomes through better diagnostics and innovative treatments.
As the prevalence of NETs continues to rise, the importance of early and accurate diagnosis is paramount. It is essential that Canadian healthcare professionals and patients remain informed about the subtleties of NETs to enhance early detection and treatment. Multidisciplinary teams across Canada are constantly working to develop and implement clinical pathways that can guide practitioners in the complex diagnostic and therapeutic landscape of NETs. With ongoing research and collaboration, there is hope for improved prognostic factors and treatment modalities, potentially transforming the outlook for Canadians living with this increasingly common group of cancers.