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Diffuse Gastric and Lobular Breast Cancer Syndrome (DGLBCS)

Diffuse gastric and lobular breast cancer syndrome (DGLBCS), formerly known as hereditary diffuse gastric cancer, is a rare genetic disorder that causes the development of multiple malignant (cancerous) tumours throughout the body. In particular, it is associated with an increased risk of developing diffuse gastric cancer and lobular breast cancer. It is caused by an alteration in the CDH1 or CTNNA1 genes.

Familial cancer syndromes, also known as hereditary cancer syndromes, are rare conditions that cause an increased risk of cancer as the result of inherited genetic mutations in certain cancer-related genes. They can affect both adults and children, however they generally develop in people at a younger age than normal. While familial cancer syndromes are not classified as cancer, they are equally as severe and can be life-threatening as they are associated with the development of various tumours throughout the body. Having a familial cancer syndrome does not guarantee the development of cancer, however the risk of developing cancer is higher than those who do not have a familial cancer syndrome.

DGLBCS tends to affect the sexes equally, and is generally diagnosed before the age of 40. However, anyone can develop this disease.

DGLBCS is associated with the development of diffuse gastric cancer and lobular breast cancer only.

Diffuse gastric cancer is a rare type of adenocarcinoma (cancer arising from mucus-producing glands in organs) that forms in the lining of the stomach. It is also known as isolated cell-type carcinoma, or signet ring carcinoma, due to an unusually large cytoplasmic vacuoles that push the nucleus to the edge of the cell, forming a signet-ring shape. This type of cancer thickens the lining of the stomach; however, it does not form a distinct mass.

Lobular breast cancer occurs when abnormal cells are found in the lobules of the breasts. It can be confined solely to the lobules (referred to as lobular carcinoma in situ (LCIS)), or spread beyond the lining of the lobules (referred to as invasive lobular carcinoma (ILC)). This type of breast cancer is diagnosed almost exclusively in females, as male breasts do not generally contain lobes and lobules.

For more information on stomach (gastric) cancer or breast cancer, please refer to our knowledgebase.

Treatment

When cancers are detected, they are staged and graded based on size, metastasis, and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you. However, each patient with DGLBCS will present with a unique disease behaviour, with varying tumour locations and symptoms. As such, there is no one treatment method that will work for everyone, and there is no standard staging system for this disease. Instead of staging and grading, your doctor will recommend a treatment plan based on the following factors:

  • Type of tumours present.
  • Whether the tumours are malignant (cancerous) or benign (non-cancerous).
  • Tumour location.
  • Whether or not malignant tumours have metastasised.
  • Your age.
  • General health.
  • Your treatment preferences.

Your doctor may also recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.

Treatment options for tumours associated with DGLBCS may include:

  • Surgery, potentially including:
    • Gastrectomy.
    • Lymphadenectomy.
    • Surgery to insert a feeding tube (often required after surgery on the stomach), such as a gastronomy tube (G-tube) or a nasogastric tube (NG tube).
    • Lumpectomy, also known as breast-conserving surgery.
    • Unilateral or bilateral mastectomy.
    • Breast reconstruction.
  • Chemotherapy.
  • Radiation therapy.
  • Hormone therapy.
  • Targeted therapy.
  • Clinical trials.
  • Palliative care.

Cancer Screening

Once a diagnosis of DGLBCS has been confirmed, implementing a targeted screening plan becomes essential due to the increased risk of developing certain cancers.  The content of this plan will vary from person to person based on the genetic mutation involved, your family’s history of cancer and the types of cancers that may be present. It will also outline the routine tests you should have and how regularly you should have them.  Some recommendations for DGLBCS may include:

  • Gastroscopy every 6-12 months beginning at age 40 or 5-10 years before the earliest gastric cancer diagnosis in the family with a minimum age of 18 years old.
  • Monthly self-breast examinations beginning at age 20.
  • Annual clinical breast examinations and bilateral breast MRI beginning at age 30.
  • Annual mammograms (between breast MRIs) beginning at age 30-40.

Screening options for DGLBCS may evolve as new technologies are developed and our understanding of the condition grows. It is essential to discuss your individual circumstances with your healthcare team to determine the most appropriate screening plan for you.

Risk factors

DGLBCS is caused by a genetic mutation in one of the following genes:

  • Cadherin-1 (CDH1) gene.
  • Alpha catenin (CTNNA1) gene.

Both CDH1 and CTNNA1 play a crucial role in cell-to-cell adhesion and maintaining tissue structure in epithelial tissue. DGLBCS is an autosomal dominant disorder, which means that you have a 50% chance of developing the condition if one of your parents carries the mutation.

Symptoms

The symptoms of DGLBCS often vary by the type(s) of tumours present. General symptoms of DGLBCS may include:

  • Unexplained weight loss and/or loss of appetite.
  • Difficulties swallowing.
  • Indigestion, which may carry its own set of symptoms:
    • Abdominal pain/burning.
    • Heartburn.
    • Frequent burping.
    • Reflux.
  • Nausea and/or vomiting.
  • Abdominal pain.
  • Feeling full after eating small quantities of food.
  • Abdominal swelling and/or bloating.
  • Fatigue.
  • Anaemia.
  • Vomit with blood in it.
  • Discoloured stools.
  • 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.
  • 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.

Symptoms related to specific tumours can be found on our knowledgebase.

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 tumours associated with DGLBCS they may order some of the following tests to confirm the diagnosis and refer you to a specialist for treatment. The tests required for diagnosis will often vary based on the symptoms present, and where the tumour(s) are suspected to be located.

  • Physical examination.
  • Genetic testing.
  • Blood tests.
  • Imaging tests, potentially including:
    • Mammogram.
    • Ultrasound.
    • MRI (magnetic resonance imaging).
    • CT (computed tomography) scan.
    • PET (positron emission tomography) scan.
  • Endoscopy, most commonly a gastroscopy.
  • Biopsy.

References

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