What is it about ?
Breast cancer is when normal breast cells turn into malignant cells. Malignant cells have the particularity of proliferating in an uncontrolled manner and being able to spread to other parts of the body (metastasize).
The exact cause is not known. But there are some risk factors: the onset of the first menstruation at an early age, late menopause, the absence of a completed pregnancy, a first pregnancy after the age of 30, prolonged use of a hormone replacement therapy (to decrease symptoms associated with menopause), obesity, exposure to ionizing radiation (eg through regular x-rays) and excessive alcohol consumption. About 5-10% of all breast cancers are associated with an inherited predisposition to breast cancer (mutations in the BRCA1 and BRCA2 genes).
Certain factors decrease the risk of breast cancer: physical activity, being a mother at a young age, having had several children, slowing down (inhibiting) the hormonal production of the ovaries before menopause with medicines or by removing the ovaries, and having the breasts surgically removed (mastectomy) in case of hereditary breast cancer.
What is its frequency?
Globally, breast cancer is the number one form of cancer in women. If you look at all the new cases of cancer, 1 in 3 times it is breast cancer. If you count all cancer deaths, 1 in 5 times the death is linked to breast cancer. In 2017, the diagnosis was made in 10,627 women living in Belgium. The prognosis has greatly improved thanks to optimal management. Currently, the 5-year survival rate is 90%. This means that 90% of women with breast cancer are still alive 5 years after diagnosis, so 9 out of 10 women.
The increase in the number of cases is mainly due to the fact that women are living longer and longer. Breast cancer is very rare before the age of 30 (0.2% of all cases), but it is significantly more common after the age of 45. Breast cancer can also affect men, but it is rare.
How to recognize it?
As soon as you feel or see something in your breasts, it is advisable to have yourself checked. A lump in a breast can be benign, but it can also be one of the (first) symptoms of breast cancer. These symptoms are:
a painless lump (lump) in the breast (in about 80% of cases),
a dimple in the skin (retraction of the skin) or a retracted nipple,
an alteration of the skin near the nipple (resembling eczema)
a tumor under the armpit,
discharge from the nipple.
How is the diagnosis made?
Triple assessment
The diagnosis is based on what is called a triple assessment: a clinical breast examination, a mammogram and the analysis of a tissue sample (biopsy) in the laboratory:
physical examination of the breast includes routine palpation of the breast and examination of the armpits to check for lymph nodes. If the doctor finds a local abnormality, he goes to the next step.
a mammogram including 2 images (1 from top to bottom and 1 from the side) and / or an ultrasound. If there are no signs of a malignant tumor, no further examinations are necessary. But if there are signs of a malignant tumor, the next step is a biopsy and tissue analysis.
microscopic analysis of breast tissue taken by biopsy: there are two techniques, namely removing a piece of breast tissue using a thick needle (core biopsy) or aspiration of cells using a fine needle (cytological puncture-aspiration). The first technique gives the best chance of success. Using a thin needle increases the risk that the doctor will prick near the lesion. In this case, the exam may give a false-negative result (it does not detect cancer, although it is still present).
Other examinations
The doctor will also test the sensitivity of the tumor type to hormones (estrogen and progesterone), as this may be important for treatment.
MRI is not performed routinely. This imaging test is only done in case of doubt, familial (hereditary) forms of cancer and recurrence after treatment.
The use of other imaging techniques, such as MIBI scintimammography with technetium administration or a PET scan, is considered on a case-by-case basis.
Detection of tumor markers in the blood is not useful for diagnosis. Tumor markers are proteins produced by the tumor itself or by the body in response to the tumor. They are mainly used to assess the effect of a treatment. When a treatment works, tumor markers decrease.