Breast cancer

Breast cancer is the most common type of cancer and the leading cause of cancer-related death among women worldwide. The number of new cases diagnosed globally exceeds 2 million.

It accounts for over 20% of female cancers and 15% of cancer-related deaths among women. Current data suggests that one in eight women will develop breast cancer at some point in their lifetime.

Risk factors for breast cancer include:
• Advanced age (>50 years),
• Early onset of menstruation (<12 years),
• Late menopause (>55 years),
• Never having given birth,
• Not having breastfed,
• Giving birth at an older age (>35 years),
• Childhood radiotherapy to the thoracic area,
• Long-term hormone replacement therapy post-menopause,
• Long-term use of oral contraceptives,
• Chronic alcohol use.

Among genetic risk factors, the most common are mutations in the BRCA1 and BRCA2 genes. Nearly half of the mutations associated with breast cancer involve BRCA1 and BRCA2. These genes are involved in DNA repair, and their mutations increase susceptibility to breast, endometrial, and ovarian cancers.

The most effective imaging methods for screening and diagnosing breast cancer are mammography and breast ultrasound. Additionally, breast magnetic resonance imaging (MRI) can be used but should not be the first choice. It is used to assist in problem-solving in cases where decisions cannot be made based on mammography and ultrasound.

Breast MRI should be used in the following situations:
• When mammography, ultrasound, and clinical examination are inconclusive,
• To investigate occult breast tumors,
• For follow-up after breast-conserving surgery (to distinguish between scar tissue and recurrence),
• To assess the response to chemotherapy or radiotherapy.

Four methods are used to perform a biopsy on a defined lesion in the breast:
1. Fine needle aspiration biopsy (FNAB)
2. Core needle biopsy (CNB)
3. Vacuum-assisted biopsy (VAB), especially useful in cases requiring extensive sampling such as atypical ductal hyperplasia (ADH) and ductal carcinoma in situ (DCIS).
4. Open surgical biopsy, which is not the first-choice technique except for the removal of non-palpable masses marked with a wire.

Patients diagnosed with breast cancer should be clinically staged before starting treatment. The TNM system is used, where T indicates the size of the primary invasive tumor, N indicates the presence of regional lymph node involvement, and M indicates the presence of distant metastasis. The Tumor, Node, Metastasis staging system is used to determine the prognosis of the disease and to decide on the treatment.

Clinical staging requires:
• Medical history,
• Physical examination,
• Radiological and laboratory tests.

Systemic spread should be investigated using PET-CT or thorax and abdomen CT, bone scintigraphy, and brain MRI. Before surgical intervention, the histopathological diagnosis of the primary tumor, indications for neoadjuvant chemotherapy, and lymph node biopsy (LNB) should be carefully evaluated.

Sentinel lymph node biopsy (SLNB) should be performed during surgery in patients without clinically detected axillary lymph node metastasis. This involves identifying and removing the sentinel lymph nodes—the first nodes to which cancer cells are likely to spread—and evaluating them pathologically. This procedure reduces morbidity by preventing lymph node dissection in patients without tumor involvement in the sentinel nodes.

Comparative studies have shown that overall survival rates are equal between simple mastectomy, breast-conserving surgery (BCS), and modified radical mastectomy (removal of almost all breast tissue, skin, and axillary lymph nodes). Therefore, the current surgical treatment approach favors breast-conserving surgery (BCS) or oncoplastic breast surgery.

Oncoplastic breast cancer surgery includes various techniques such as segmental/segmental mastectomy, lumpectomy, partial mastectomy, and wide local excision. The full definition of this surgical procedure involves removing the tumor with surrounding healthy tissue to ensure negative surgical margins (clean and more than 1 mm safe margin), marking and pathologically confirming the safety of the axillary lymph node (frozen section), and if necessary, removing additional lymph nodes for pathology. This ensures a safe oncological surgical outcome.

Oncoplastic breast cancer surgery helps reduce stress disorders and supports psychosocial recovery and the success of oncological treatment. This method, proven effective and successful in numerous studies over the past 15 years, is particularly recommended for patients diagnosed with breast cancer, where surgery or oncological treatment is prioritized after body scanning. The procedures of oncoplastic breast cancer surgery are applied according to the tumor localization.