Biopsy is a critical step in the diagnosis of neuroendocrine tumours (NETs), providing essential information that guides treatment decisions and prognosis.
The role of a biopsy is multifaceted and can:
For NET patients, an accurate biopsy can mean the difference between standardised care and a personalised treatment plan that addresses the specific characteristics of their tumour.
Neuroendocrine Cancer Australia (NECA), is dedicated to supporting individuals diagnosed with NETs, 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.
Tumour biopsy is an essential diagnostic step when treating NETs. In the end, a biopsy is the gold standard for confirming a diagnosis of neuroendocrine cancer.
Confirming diagnosis and tumour type
While imaging studies can suggest the presence of a tumour, only a biopsy can provide the definitive cellular evidence needed to confirm that the mass is a NET.
This confirmation is crucial. NETs can vary widely in their behaviour and treatment requirements depending on their origin and cell type.
Understanding tumour grade and differentiation
Beyond confirming the presence of a tumour, a biopsy is also vital for understanding the tumour’s grade and level of differentiation.
Low-grade, well-differentiated tumours tend to grow more slowly and have a better prognosis, whereas high-grade, poorly differentiated tumours are often more aggressive.
Guiding treatment decisions
The information obtained from a biopsy not only helps in diagnosing and grading the tumour but also plays a crucial role in guiding treatment decisions.
Understanding the tumour’s characteristics enables healthcare providers to tailor treatment strategies to the individual needs of the patient, potentially improving outcomes and quality of life.
For instance, a biopsy can guide a healthcare team to choose individualised treatment options:
Biopsy is not simply cutting away a sample of tumour and sending it off to a lab for analysis. It involves a range of different methodologies depending on the patient.
Fine-needle aspiration (FNA) is a minimally invasive biopsy technique where a thin, hollow needle is inserted into the tumour to extract a small sample of cells. This procedure is typically guided by imaging techniques such as ultrasound or CT scans to ensure accurate targeting of the tumour.
FNA is commonly used for:
Core needle biopsy is similar to FNA but uses a larger needle to remove a small cylinder of tissue, providing a more substantial sample. This method allows for better architectural analysis of the tumour cells, which can be crucial for accurate diagnosis and grading.
Core needle biopsy is commonly used for:
Endoscopic retrograde cholangiopancreatography (ERCP) is another endoscopic technique used to biopsy tumours in the bile ducts and pancreas. During this procedure, a flexible tube with a camera (endoscope) is passed through the mouth, down the digestive tract, and into the bile ducts. Biopsies taken during ERCP are often critical in diagnosing biliary and pancreatic NETs.
ERCP is commonly used for:
An excisional biopsy involves the complete removal of a tumour or lymph node for analysis. This procedure is typically performed when the tumour is easily accessible and relatively small, allowing for the entire mass to be removed and examined.
Excisional biopsy is commonly used for:
In contrast to excisional biopsy, incisional biopsy involves the removal of only a portion of the tumour. This method is used when the tumour is too large to be removed entirely without causing undue harm to the patient.
Incisional biopsy is commonly used for:
Bone marrow biopsy is performed to assess whether NETs have spread to the bone marrow, a site that can be involved in some cases of advanced disease. This procedure involves the removal of a small amount of bone marrow tissue, usually from the pelvis, using a special needle.
Bone marrow biopsy is commonly used for:
Liquid biopsy is an emerging technique that analyses circulating tumour cells, DNA, or other biomarkers found in the blood. This non-invasive method is gaining attention for its potential to provide valuable diagnostic information without the need for a traditional tissue biopsy.
Liquid biopsy is commonly used for:
The choice of biopsy technique largely depends on the location and accessibility of the tumour. For superficial or easily accessible tumours, FNA or core needle biopsy may be sufficient.
However, for deep-seated tumours or those in sensitive areas like the pancreas, endoscopic or surgical biopsies may be necessary. The goal is to obtain an adequate tissue sample with minimal risk to the patient.
Patient health is another critical factor in determining the appropriate biopsy technique. For patients with underlying health conditions or those at higher risk for complications, a care team might choose less invasive procedures like FNA or liquid biopsy.
Conversely, for patients who can tolerate more invasive procedures, surgical biopsy may provide the most comprehensive diagnostic information.
While biopsy procedures are generally safe, they do carry some risks. Potential complications include bleeding, infection, and in rare cases, tumour seeding along the needle tract. The risk of these complications varies depending on the type of biopsy and the patient’s overall health.
It is important for healthcare providers to weigh these risks against the benefits of obtaining a definitive diagnosis.
Once a biopsy sample is obtained, what happens next? It’s immediately sent away for pathological analysis, where it will undergo a range of tests to fully ascertain the type, grade, and stage of the tumour.
Biopsy results are essential for grading and staging NETs. Grading is based on the tumour’s appearance and proliferation rate, while staging considers the tumour’s size, location, and spread to other parts of the body.
Once a biopsy sample is obtained, it undergoes pathological analysis, which includes histopathology and immunohistochemistry.
Biomarkers such as chromogranin A, synaptophysin, and Ki-67 can provide information about the tumour’s activity and proliferation rate.
Genetic testing may also reveal mutations that could influence treatment decisions, such as the presence of somatic mutations that make a tumour more or less responsive to certain therapies.
As will all kinds of diagnostic and treatment methods for managing cancer, biopsy poses a set of challenges to both patients and healthcare teams. In the realm of NETs, these challenges are particularly pronounced due to the obscure nature of the condition.
Tumour heterogeneity is where different parts of the tumour may have different characteristics. This can make it difficult to obtain a representative sample, potentially leading to an incomplete or inaccurate diagnosis.
Some methods produce small sample sizes, which may not always provide enough tissue for a conclusive diagnosis. In such cases, a repeat biopsy or a more invasive procedure may be necessary to obtain an adequate sample.
There is also the risk of non-diagnostic biopsies, where the sample obtained does not provide enough information to confirm a diagnosis. This can occur if the needle misses the tumour or if the sample is too small or degraded. Non-diagnostic biopsies may necessitate additional procedures, which can delay diagnosis and treatment.
Biopsies are not only used for initial diagnosis but also play a role in ongoing treatment and monitoring. Repeat biopsies may be performed to assess disease progression, particularly if there is a suspicion that the tumour has changed in grade or behaviour. Monitoring through biopsy helps ensure that the treatment plan remains effective and can be adjusted as needed.
Accurate biopsy results are fundamental to patient care, enabling personalised treatment plans that target the specific characteristics of the tumour. By ensuring that the diagnosis is precise, healthcare providers can avoid unnecessary treatments and focus on therapies that are most likely to be effective.
Advances in biopsy techniques, such as liquid biopsy and image-guided procedures, are helping to minimise the need for invasive procedures. Precision biopsy techniques reduce patient discomfort and recovery time while still providing the critical information needed to guide treatment.
Further information and support for people diagnosed with NETs is available by calling the NECA NET nurse line.
