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Breast cancer comprises a group of malignancies of the epithelium of the ducts and lobules of the mammary gland, with different molecular characteristics and clinical behaviour.

It is the most common cancer affecting women worldwide, accounting for one in three cancers diagnosed in women. It is the leading cause of death among women in the developing world and the second leading cause of death among women in the developed world.

In Greece, approximately 4,000 new cases of breast cancer are diagnosed each year, and 2,500 women die annually from this cause.

The exact cause of breast cancer remains unknown. Factors whose presence is associated with an increased risk of developing breast cancer have been identified, including sex (female), age (incidence increases with age), heredity (especially the presence of mutated genes), hormonal factors (a high number of ovulatory cycles, childlessness, first pregnancy after the age of 30, hormone replacement therapy) and lifestyle-related factors (lack of exercise, obesity, consumption of alcohol and animal fats).
Heredity is associated with 10% of breast cancers, while 5% are attributed to the presence of mutations in the BRCA1 and BRCA2 genes. Carriers of these genes are considered to be at particularly high risk of developing breast cancer (70%) and ovarian cancer (60%) during their lifetime and require specialised monitoring and management programmes.

Breast cancer is usually asymptomatic, with no pain or other manifestation. It is usually noticed by the woman as a palpable, painless and persistent lump.

Symptoms or signs that may also indicate the presence of the disease include recent non-reversible nipple retraction, loss of the breast’s normal contour, skin retraction and nipple discharge, especially when blood is present. Early diagnosis is the key to the successful treatment of breast cancer.

Methods of early diagnosis include self-examination, clinical examination by a specialist physician, mammography, ultrasound, breast MRI and fine-needle or core-needle biopsy.

Mammography, whether analogue or digital, is the established method of early diagnosis because of its ability to reveal calcifications that often indicate the early presence of cancer.

In recent decades, extensive mammographic screening programmes for asymptomatic women in many countries have confirmed its effectiveness, achieving a reduction in breast cancer mortality, particularly among postmenopausal women.

Preventive mammographic screening is an individualised process, and its schedule is determined by a specialist physician in consultation with the woman being examined, based on an assessment of each woman’s risk factors.

Risk factors include:

• The presence of mutated BRCA1 and BRCA2 genes (a very high-risk group, with a risk exceeding 50%) or another moderate-risk gene (risk below 50%),
• Heredity, with the presence of breast or ovarian cancer in more than two relatives, especially at a young age,
• Therapeutic radiotherapy to the chest-wall area at a young age (19 to 30 years),
• The presence of atypical epithelial hyperplasia or lobular carcinoma in situ in a previous breast biopsy (a 5- to 20-fold increase in risk),
• Dense breasts and a personal history of breast or ovarian cancer.

In general, for women at average or low risk, a typical monitoring programme includes:

• For women under the age of 40, preventive mammographic screening offers no benefit. Clinical examination and ultrasound are recommended from the age of 25,
• Beginning mammographic screening at the age of 40,
• Annual mammographic screening between the ages of 40 and 49,
• From the age of 50 onwards, mammographic screening every one to two years, depending on the assessed risk and breast density,
• Discontinuation of preventive screening at the age of 75 or when life expectancy is less than five years,

For women at very high risk, a specialised protocol is followed, with mammographic screening beginning at a younger age and breast MRI being added to breast monitoring.

A recent development in mammography is 3D mammography, or tomosynthesis, which helps in the evaluation of dense breasts and the clarification of mammographic findings.

Ultrasound is the examination of choice for the breasts of younger women and for the assessment of mammographic findings and dense breasts.

Core-needle biopsy for histological examination or fine-needle aspiration (FNA) for cytological examination is necessary for the histological identification of lesions detected through imaging. These procedures are painless, simple, low-cost and safe, and they are essential for the preoperative assessment of a cancer’s molecular characteristics.

The treatment of breast cancer requires a multidisciplinary approach (tumour board), involving a surgeon, radiation oncologist and medical oncologist, with the additional support of a radiologist, pathologist, geneticist, molecular biologist and psychologist.

Preoperative histological identification of the cancer through an ultrasound-guided core-needle biopsy is necessary for planning the treatment strategy. Depending on their molecular characteristics, approximately 30% of breast cancers (triple-negative and HER2-positive) have better outcomes when treated with preoperative chemotherapy.

The main surgical procedures are lumpectomy (removal of the tumour with disease-free margins) and mastectomy. Staging of the axillary lymph nodes is necessary for both procedures. In recent years, the adoption of the sentinel lymph-node technique in axillary surgery has minimised the morbidity (painful shoulder, lymphoedema) associated with extensive lymph-node dissection.

In lumpectomy procedures, radiotherapy to the affected breast must also be administered.

Systemic treatments (chemotherapy, immunotherapy and hormone therapy) are determined by the tumour’s molecular characteristics. The recent addition of genomic assays (Oncotype DX and MammaPrint) makes it possible to select the most appropriate systemic treatment and avoid unnecessary therapeutic interventions.

The personalised selection of medicines for chemotherapy and hormone therapy, the addition of immunotherapy (precision medicine), the widespread adoption of preventive mammographic screening and improvements in imaging techniques have contributed to a 40% reduction in breast cancer mortality over recent decades.

This demonstrates the need for broader and more consistent participation by women in the available opportunities for preoperative screening and for treatment at a specialised centre.