Breast Cancer

Breast Cancer

Breast cancer initiates in the breast tissue and is categorized into two primary types:

1. Ductal carcinoma originates in the milk-carrying ducts.
2. Lobular carcinoma originates in the milk-producing lobules.

In rare instances, breast cancer may develop in other breast areas. Breast cancer can be invasive, having spread beyond ducts or lobules, or noninvasive, confined to its originating site, also known as "in situ."

Ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS) represent noninvasive forms of breast cancer, confined respectively to ductal linings and lobular regions. DCIS, if untreated, can progress to invasive cancer. LCIS indicates an elevated risk of invasive cancer in one or both breasts.

Many breast cancers exhibit sensitivity to estrogen, stimulating tumor growth. Such cancers, termed estrogen receptor-positive (ER-positive), possess estrogen receptors on cell surfaces. Another subtype, HER2-positive breast cancer, features excessive HER2 gene expression, indicating a more aggressive disease course with heightened recurrence risk.

Causes, Incidence, and Risk Factors

Over a lifetime, approximately 1 in 8 women will confront breast cancer. Immutable risk factors include age, gender (women being significantly more susceptible), and familial breast cancer history, with up to 30% of cases associated with family cancer lineage. Genetic predisposition, particularly mutations in the BRCA1 and BRCA2 genes, elevates breast cancer risk, as do hormonal factors like early menarche and late menopause. Additional risk factors encompass alcohol consumption, nulliparity or delayed childbirth, diethylstilbestrol (DES) exposure, prolonged hormone replacement therapy (HRT), obesity, and prior chest radiation. Conversely, breast implants, antiperspirant use, and wearing underwire bras do not heighten breast cancer risk, nor does evidence support a direct link between breast cancer and pesticides.

Symptoms

Early breast cancer often manifests asymptomatically, underscoring the importance of regular breast examinations. As cancer progresses, symptoms may include palpable breast lumps, axillary lymphadenopathy, changes in breast or nipple appearance, and nipple discharge. Men may also develop breast cancer, typically presenting with breast masses or tenderness. Advanced breast cancer may feature skeletal pain, skin ulceration, arm edema, and unintentional weight loss.

Signs and Tests

Diagnostic evaluation involves a comprehensive medical history, physical examination encompassing breast, axillary, and cervical regions, and various imaging and laboratory tests. Diagnostic modalities include breast MRI, ultrasound, mammography, breast biopsy, CT scan, PET scan, and sentinel lymph node biopsy. Staging aids in treatment planning and prognosis estimation, ranging from stage 0 to IV based on cancer advancement.

Treatment

Treatment strategies hinge on cancer type, stage, and hormonal and genetic profiles. Therapeutic modalities encompass surgery, chemotherapy, radiation therapy, hormonal therapy, and targeted therapy. Surgical options range from lumpectomy to mastectomy, often combined with lymph node excision. Hormonal therapy targets ER-positive tumors, blocking estrogen signaling pathways. Targeted therapies such as trastuzumab address HER2-positive cancers. Treatment aims to eradicate cancer, prevent recurrence, or alleviate symptoms, with adjuvant therapies tailored to cancer stage and patient needs. Follow-up care includes surveillance imaging, blood tests, and ongoing monitoring to ensure optimal outcomes. Reconstruction surgery may be offered post-mastectomy to enhance cosmetic outcomes and psychological well-being.