by Neuroendocrine Tumors: An Overview
Neuroendocrine tumors, also known as NETs, are a group of rare tumors that develop in the neuroendocrine cells of the body. These cells are found throughout the body’s organ systems and help regulate a variety of functions using hormone signals. NETs can develop in tissues and organs that contain neuroendocrine cells such as the lungs, pancreas, stomach, small intestine, colon, rectum, testicles, and ovaries.
According to a recent study, the incidence of NETs has been increasing over the past few decades. However, many people still know relatively little about these types of tumors. NETs grow slower as compared to other cancers but can still spread to other parts of the body if not detected and treated early. The signs and symptoms of NETs may not appear till the tumor has spread. This makes diagnosis and treatment challenging.
Staging and Grading of NETs
For effective treatment of NETs, doctors need to understand the extent or stage of the disease. Staging helps determine how widespread the cancer is. It is based on tumor size, involvement of nearby tissues or lymph nodes and presence of distant metastases.
Besides staging, grading is another important aspect in NET management. Grading refers to how abnormal the cancer cells look under a microscope and how fast the tumor is likely to grow and spread. The grade depends on factors like number of mitoses and Ki-67 index. Well differentiated or low grade NETs have a better prognosis compared to poorly differentiated or high grade ones.
Treatment Based on Stage and Grade
The initial Neuroendocrine Tumor Treatment approach depends on the site of origin, stage and grade of the NET. For localized or localized and regional disease, surgery to remove the primary tumor remains the mainstay of treatment. Adjuvant therapies may also be used depending on risk factors.
For advanced or metastatic NETs, a multi-disciplinary team is needed to determine the best treatment plan. Options include somatostatin analogs, targeted drug therapy, chemotherapy, embolization or ablation procedures, peptide receptor radionuclide therapy and in selected cases, liver-directed surgery or liver transplant. Clinical trials evaluating new drugs are also an option.
The goal is to control symptoms, slow disease progression and ideally induce tumor shrinkage. Treatment is usually lifelong as NETs have a tendency for late recurrences. Close monitoring plays a vital role to detect relapse at an early stage. Let us look at some of the major advances in NET treatment in recent years.
Advances in Systemic Therapy
Systemic therapy refers to use of drugs to affect the entire body rather than just the tumor. Significant progress has been made in this area for managing advanced NETs.
Somatostatin analogs or SSA like octreotide and lanreotide are established first-line options. They help control symptoms in 55-90% of NET patients by suppression of hormonal hypersecretion. New long-acting formulations allow less frequent dosing.
Tyrosine kinase inhibitors that target angiogenesis pathways have shown promising results. Drugs like sunitinib and everolimus have gained FDA approval based on phase III trials. They demonstrate antiproliferative effects and significantly prolong progression-free survival.
Newer targeted therapies under research include mTOR inhibitors, BET inhibitors, DLL3 antibody-drug conjugates, NET specific chemo drugs and vaccines. Combination regimens are also being evaluated to achieve better outcomes.
Advances in Local and Regional Therapies
Improved interventional and surgical procedures have enhanced local disease management. Embolization helps in selective internal radiation therapy using radioactive microspheres that lodge in the tumor vasculature. Peptide receptor radionuclide therapy delivers radiation specifically to NET cells.
Advancements in ablation techniques allow precise tumor destruction with minimal damage to surrounding tissues. Cryoablation, radiofrequency ablation, microwave and high intensity focused ultrasound are options based on tumor type and location.
Image-guided minimally invasive surgeries for liver and lung metastases now achieve resectability in select previously unresectable cases. Laparoscopic and robotic assisted resections provide better recovery over open techniques. Aggressive cytoreduction combined with hepatic arterial embolization or ablation can benefit patients with extensive unresectable disease.
Neuroendocrine tumors originating from the neuroendocrine system pose unique management challenges. However, with a better understanding of molecular pathogenesis and advancement in diagnostic tools, targeted drugs, interventional procedures and surgical techniques, treatment outcomes continue to improve. An individualized multidisciplinary care approach utilizing all available therapeutic options improves survival and quality of life for NET patients. Future research focusing on precision medicine and combination regimens may further revolutionize NET care.
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1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
