Breast Cancer: Symptoms, Diagnosis and Current Treatment Options

What is breast cancer?

Breast cancer most often starts in the milk ducts (ductal) or the milk glands (lobular). Three main biological groups stand out for treatment: hormone receptor-positive / HER2-negative, HER2-positive and triple-negative breast cancer. Tumours with low HER2 levels (HER2-low) are now also considered a separate group that influences the choice of treatment [3][4].

What causes breast cancer? Risk factors

The main factors that increase the risk are female sex, older age, a history of breast or ovarian cancer in first-degree relatives and inherited gene alterations such as BRCA1/BRCA2 [5]. Alcohol use, excess weight after menopause, physical inactivity, early menarche or late menopause, long-term hormone replacement therapy and radiotherapy to the chest area at a young age may also increase the risk [1]. Breast cancer can also occur in men, but it is much rarer.

How common is breast cancer?

According to World Health Organization data, about 2.4 million women worldwide were diagnosed with breast cancer in 2024; it is the most common cancer in women [1].

What are the symptoms of breast cancer?

• A newly noticed hardness or lump in the breast or armpit
• A change in the size or shape of the breast
• Skin dimpling, redness or an orange-peel appearance
• Nipple retraction or bloody discharge

A large proportion of breast lumps are benign; even so, a physician should be consulted without delay when a new change is noticed.

How is breast cancer diagnosed?

Mammography and breast ultrasound are the basic imaging methods; breast MRI is added when needed. The definitive diagnosis is made by needle (core) biopsy. On pathological examination, oestrogen and progesterone receptors (ER/PR), HER2 and Ki-67 are assessed. For staging, tumour size, lymph node involvement and, if necessary, CT, bone scintigraphy or PET-CT are used [3].

Genetic tests

In patients who meet the appropriate criteria, testing for inherited BRCA1/2 alterations is recommended; the result can affect both the choice of treatment and the screening of family members [5]. In early-stage hormone-positive disease, gene expression tests can help assess the need for chemotherapy [3].

How is breast cancer treated?

Treatment is determined by considering the stage, biological subtype and the patient’s preferences together. Assoc. Prof. Dr. Ali Oğul’s approach is to evaluate the treatment plan in a multidisciplinary tumour board together with specialists in general surgery, radiation oncology, radiology and pathology.

Surgery and radiotherapy

Breast-conserving surgery or mastectomy is performed together with assessment of the axillary lymph nodes (sentinel lymph node biopsy). Radiotherapy is usually given after breast-conserving surgery [3].

Hormone receptor-positive disease

Hormone therapy (tamoxifen or aromatase inhibitors) is the mainstay and usually lasts 5–10 years. In high-risk early-stage and metastatic disease, CDK4/6 inhibitors can be added to hormone therapy [2][3][4].

HER2-positive disease

Drugs that target HER2, such as trastuzumab and pertuzumab, are used together with chemotherapy; treatment is often started before surgery. In metastatic disease and in HER2-low tumours, antibody-drug conjugates such as trastuzumab deruxtecan are among the options [2][4].

Triple-negative disease and BRCA mutation

In early-stage triple-negative breast cancer, immunotherapy can be added to chemotherapy given before surgery. In selected patients with an inherited BRCA mutation, PARP inhibitors can be used [2][3].

Latest regulatory updates for this cancer type: Breast Cancer: Latest Developments

Side effects and follow-up during treatment

Hormone therapy can cause hot flushes, joint pain and a decrease in bone density; with HER2-targeted treatments, heart function is monitored regularly. After treatment, follow-up is done with examinations at set intervals and an annual mammogram.

Can breast cancer be prevented?

It is not possible to remove the risk completely; however, a healthy weight, regular physical activity and avoiding alcohol can reduce it. Within the national screening programme in Türkiye, a mammogram every two years is recommended for women aged 40–69 [6]. In women with an inherited risk, screening can be planned at an earlier age and with MRI [5].