What Are Neuroendocrine Tumours?
Neuroendocrine tumours (NETs) arise from neuroendocrine cells, which are found throughout the body. These cells have features of both nerve cells and hormone-producing cells. NETs can occur in many organs, with the gastrointestinal tract, pancreas, and lungs being the most common sites.
NETs differ from more common cancers in several ways. They often grow slowly, though some can be aggressive. Many NETs produce hormones, which can cause specific symptoms depending on which hormone is overproduced. The rarity and variable behaviour of NETs means that specialised diagnostic and treatment approaches are often needed.
The Role of Nuclear Medicine in Diagnosis
Many neuroendocrine tumour cells carry somatostatin receptors on their surface. This makes them ideal targets for nuclear medicine imaging. A Ga-68 DOTANOC PET CT scan uses a tracer that binds to these somatostatin receptors, highlighting NET cells wherever they are in the body.
This scan is often more sensitive than conventional CT or MRI for detecting NETs, particularly small tumours or lesions in the liver and lymph nodes. It also provides important information about whether the tumour cells express somatostatin receptors, which directly determines eligibility for certain treatments.
An FDG PET CT may also be performed in some cases, particularly for higher-grade or more aggressive neuroendocrine cancers that may not express somatostatin receptors as strongly.
Lu-177 DOTATATE Therapy
For patients with NETs that express somatostatin receptors (confirmed by a positive DOTANOC or DOTATATE PET CT scan), Lu-177 DOTATATE therapy is a targeted treatment option. This radioligand therapy uses the same somatostatin receptor targeting mechanism for treatment that was used for diagnosis.
Lu-177 DOTATATE binds to the somatostatin receptors on NET cells and delivers targeted beta radiation. The treatment is given as an intravenous infusion, typically over four cycles spaced approximately 8 weeks apart. Between cycles, blood tests and imaging assess the response and monitor for side effects.
Clinical evidence has shown that Lu-177 DOTATATE can slow tumour progression and improve quality of life in patients with advanced, somatostatin receptor-positive NETs. As with any cancer treatment, responses vary between patients, and the decision to proceed is made after careful evaluation by the treating team.
A Theranostic Approach
The management of NETs through nuclear medicine is a clear example of theranostics in action. The diagnostic scan identifies the target, and the therapy exploits that same target for treatment. This personalised approach selects patients who are most likely to benefit and avoids treating patients whose tumours lack the necessary receptor expression.
Working with Your Medical Team
If you have been diagnosed with a neuroendocrine tumour, ask your oncologist about the role of somatostatin receptor imaging and whether Lu-177 DOTATATE therapy could be relevant to your case. NETs require a multidisciplinary approach, and nuclear medicine plays an important role in both the diagnostic workup and the treatment options for this group of cancers.