Neuroendocrine breast cancera disease where abnormal cells split without control and spread to other nearby body tissue and/or organs (NECB), also known as mammary neuroendocrine tumours (NETs), are a very rare type of cancer that develops in the breast, a glandular organ situated over the ribcage. While men and women both have breasts, the anatomy of the breast is slightly different between the sexes.
Breasts in females are functional organs that are used to produce milk during and after pregnancy. Female breasts are primarily made up of lobes, lobules, and ducts, which are surrounded by fatty and connective tissuea group of cells that work together to perform a function. Each breast is divided into 12-20 sections called lobes. Each lobe is made up of lobules that produce breast milk, which is then sent to the ducts. The ducts in the breasts carry milk to the nipple to be fed to babies.
In males, the breast is a non-functional organ that cannot produce milk. Unlike female breasts, male breasts do not generally contain lobes and lobules. Ducts are present in male breasts, however they do not have a function.
Neuroendocrine cancers are a complex group of tumours that develop in the neuroendocrine system, which is responsible for regulating important bodily functions such as heart rate, bloodthe red bodily fluid that transports oxygen and other nutrients around the body pressure and metabolism. They most commonly develop in the gastro-intestinal tract, pancreasa long, flat organ that sits between the stomach and the spine that plays a key role in digestion and blood sugar regulation, and the lungs; however, they can develop anywhere in the body. These tumours develop from neuroendocrine cellsthe basic structural and functional unit of all living things, which are responsible for receiving signals from the nervous system and producing hormones and peptides (small proteins) in response.
NECBs are more common in women, and tend to be diagnosed over the age of 50. However, anyone can develop this disease.
Types of Neuroendocrine Breast Cancer
NECB can be categorised into three main subtypes based on cell type and behaviour.
Well-Differentiated Neuroendocrine Tumour of the Breast
Well-differentiated neuroendocrine tumours of the breast are a rare type of cancer that are characterised by relatively ‘normal looking’ cells under the microscope. These tumours are often categorised as low-grade (slow growing), however can metastasise if left untreated.
Neuroendocrine Carcinomas of the Breast
Neuroendocrine carcinomas of the breast are a rare type of cancer that are characterised by abnormal looking cancer cells under the microscope. There are two primary subtypes of this disease.
Small Cell Carcinoma of the Breast
Small cell carcinomacancer arising from tissues that line organs of the breast is a very rare form of cancer that is often classified as a type of extrapulmonary small cell lung cancer, as the cells present are identical under a microscope. Unfortunately, small cell carcinomas of the breast are often aggressive, and may not have as good of a prognosisto predict how a disease/condition may progress and what the outcome might be as other types of breast cancers.
Large Cell Carcinoma of the Breast
Large cell carcinomas of the breast are a very rare form of cancer that is often associated with large cell undifferentiated carcinoma of the lungs. Unfortunately, large cell carcinomas of the breast are often aggressive, and may not have as good of a prognosis as other types of breast cancers.
Invasive Breast Cancers of No Special Type (IBC-NST) with Neuroendocrine Differentiation
Invasive breast cancers of no special type (IBC-NST) with neuroendocrine differentiation are a rare subtype of breast cancer that encompasses various types of invasive breast cancers that have features of neuroendocrine tumours. Because of how rare this subtype is, there has been limited research done into the behaviour and prognosis of this disease.
Treatment
If a NECB is detected, it will be staged and graded based on size, metastasiswhen the cancer has spread to other parts of the body, also known as mets, and how the cancer cells look under the microscope. Stagingthe process of determining how big the cancer is, where it started and if it has spread to other areas and grading helps your doctors determine the best treatment for you.
Cancers can be staged using the TNM staging system:
- T (tumoura tissue mass that forms from groups of unhealthy cells) indicates the size and depth of the tumour.
- N (nodea small lump or mass of tissue in your body) indicates whether the cancer has spread to nearby lymph nodessmall bean-shaped structures that filters harmful substances from lymph fluid.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissue.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localisedaffecting only one area of body cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advancedat a late stage, far along or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Gradea description of how abnormal cancer cells and tissue look under a microscope when compared to healthy cells I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testinga procedure that analyses DNA to identify changes in genes, chromosomes and proteins, which can be used to analyse tumour DNA to help determine which treatment has the greatest chance of success, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. This is often performed after a biopsyremoval of a section of tissue to analyse for cancer cells, and can help guide treatment options for you.
Treatment is dependent on several factors, including location, stage of disease and overall health.
Treatment options for NECB may include:
- Surgerytreatment involving removal of cancerous tissue and/or tumours and a margin of healthy tissue around it to reduce recurrence, potentially including:
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- Lumpectomya surgical procedure where the tumour and a small amount of surrounding breast tissue are removed, also known as breast conserving surgery, also known as breast-conserving surgerya surgical procedure where the tumour and a small amount of surrounding breast tissue are removed, also known as a lumpectomy.
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- Unilateralaffecting one side or bilateralaffecting both sides mastectomycomplete or partial removal of one or both breasts.
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- Breast reconstructiona surgery to recreate a natural-looking breast after a mastectomy.
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- Lymphadenectomysurgical removal of lymph node(s).
- Radiation therapya treatment that uses controlled doses of radiation to damage or kill cancer cells, potentially including peptide receptor radionuclide therapy (PRRT)a targeted cancer treatment that uses radioactive substances (radionuclides) to deliver radiation directly to tumour cells.
- Chemotherapya cancer treatment that uses drugs to kill or slow the growth of cancer cells, while minimising damage to healthy cells.
- Hormone therapymedication that alters the levels of certain hormones in the body, such as oestrogen and progesterone.
- Somatostatin analogues (SSAs)medication used to inhibit excessive hormone production .
- Clinical trialsresearch studies performed to test new treatments, tests or procedures and evaluate their effectiveness on various diseases.
- Palliative carea variety of practices and exercises used to provide pain relief and improve quality of life without curing the disease.
Breastfeeding and Breast Cancer Treatment
Treatment for NECB may affect your ability to breastfeed. If this is a concern to you, discuss your options with your doctor prior to the commencement of treatment.
Risk factors
Because of how rare NECBs are, there has been little research done into the riskthe possibility that something bad will happen factors of this disease.
Symptoms
Some patients with NECB will appear asymptomatic in the early stages of disease. As the tumour progresses, some of the following symptoms may appear:
- A lump or lumpiness in the breast(s).
- A change in the size and/or shape of the breast.
- Swollen breasts.
- Changes to the nipple, potentially including:
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- Changes in shape.
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- Crusting, sores and/or ulcers.
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- Unusual redness.
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- Pain.
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- Clear or bloody discharge.
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- Inverted nipple (nipple turns inward when it used to face outward).
- Dimpling or indentation on the skin of the breast.
- A rash and/or itchiness of the breast.
- A scaly appearance and/or changes in the colour of the breast.
- Swelling or discomfort in the armpit or near the collarbone.
- Persistent, unusual pain not associated with the menstrual cycle.
- Carcinoid syndrome (rare), which carries its own set of symptoms:
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- Facial flushing (usually red or purple in the face, neck, and/or upper chest).
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- Diarrhoeafrequent discharge of watery or loose stools from the body.
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- Wheezing.
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- Abdominal pain.
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- Carcinoid heart disease (plaques on the heart muscle caused by excess hormonea chemical substance produced by glands in the endocrine system that regulates various functions in the body production).
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- Faecal urgency.
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- Fatiguea state of extreme tiredness or exhaustion, can be physical or mental.
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- Skin changes, such as red or purple spots on the face, neck, and/or upper chest.
- Paraneoplastic syndromesa group of rare disorders that occur when the immune system has a reaction to a cancerous tumour within the body (rare).
- Hypercalcaemiaexcess levels of calcium in the blood (rare).
Not everyone with the symptoms above will have cancer, but see your general practitioner (GP) if you are concerned.
Diagnosis
If your doctor suspects you have a NECB, they may order the following tests to confirm the diagnosisthe process of identifying a disease based on signs and symptoms, patient history and medical test results and refer you to a specialist for treatment:
- Physical examinationan examination of your current symptoms, affected area(s) and overall medical history.
- Imagingtests that create detailed images of areas inside the body tests, potentially including:
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- Mammograma type of medical imaging that uses x-rays to create detailed images of breast tissue.
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- Ultrasounda type of medical imaging that uses soundwaves to create detailed images of the body .
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- MRI (magnetic resonance imaging)a type of medical imaging that uses radiowaves, a strong magnet and computer technology to create detailed images of the body.
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- CT (computed tomography) scana type of medical imaging that uses x-rays and computer technology to create detailed images of the body.
- Blood teststesting done to measure the levels of certain substances in the blood.
- Biopsy.