Breast cancer is the most commonly diagnosed malignancy in women in the Western countries, and accounts for more than 25% of cancers diagnosed in women worldwide.
Early-stage breast cancer and ductal carcinoma in situ (DCIS) are usually asymptomatic, and diagnosed via screening programs. Common clinical signs and symptoms include breast lumps, axillary mass, nipple discharge, or bleeding. Inflammatory breast cancer may present with erythema, pain, and peau d’orange in the affected breast.
Work up for diagnosis of breast includes complete history and physical examination, imaging studies, and laboratory tests. Tissue diagnosis is mandatory prior to initiating treatment. Results from pathology are also critical for determining prognosis and tailoning systemic therapy (chemotherpay, hormonal therapy, and targeted therapy).
Stage at diagnosis is the most important prognostic factor. Overall survival (OS) rates at 5 years range from >95% in stage I to <15% in stage IV diseases. Other important prognostic factors include molecular markers, oncogenes, as well as estrogen-receptor (ER), progesterone-receptor (PR), and HER2 status.
The probabilities of regional lymph node (including axillary, supraclaviclar, and internal mammary nodes) metastases depend on the size and location of the primary disease. The commonly observed distant metastatic sites include liver, brain, lung, and bone.
For early stage disease, breast-conserving therapy (BCT) using lympectomy and radiation therapy is the preferred approach. Adjuvant hormonal and/or chemotherapy further improves overall survival (OS) in selected stages I–IIA cases.
Mastectomy followed by chemotherapy with/without radiation therapy is the treatment of choice for locally advanced breast cancer. Neoadjuvant chemotherapy followed by BCT (if feasible) or mastectomy. Postmastectomy radiation improves disease free survival and overall survival (OS) according to published metanalysis. Inflammatory breast cancers are usually treated with neoadjuvant chemotherapy followed by mastectomy and radition therapy.
Hypofractionated radiation therapy or standard dose-fractionation can be considered for BCT in early-stage invasive breast cancer. 3D-conformal radiation therapy or intensity-modulated radiation therapy (forward plan or inverse planning) is recommended for whole-breast irradiation.
Accelerated partial-breast irradiation can be used in select patients with early-stage disease after lumpectomy
In locally advanced disease standard RT dose fractionation is recommended after mastectomy.
Systemic hormonal therapy and chemotherapy, with or without targeted therapy, are the mainstay treatments for non-metastatic high risk node negative disease, node positive disease, and all metastatic breast cancer.