What is breast cancer from a to z in details, specifically regarding its etiology, diagnosis, treatment, and management of breast cancer (Carcinoma of the breast)?

From the Guidelines

Breast cancer is a complex and multifaceted disease that requires a comprehensive approach to diagnosis, treatment, and management, with the goal of optimizing outcomes and improving quality of life for patients.

Etiology and Risk Factors

Breast cancer is the most common malignancy in women in the United States, with a high mortality rate, and its etiology is multifactorial, involving genetic, hormonal, and environmental factors 1. Risk factors include female gender, increasing age, family history, genetic mutations (BRCA1/BRCA2), early menstruation, late menopause, and lifestyle factors such as maintaining a healthy weight, regular exercise, and limiting alcohol consumption.

Diagnosis

Diagnosis involves imaging (mammogram, ultrasound, MRI) and biopsy, with a pathological report that includes the histological type, grade, ER status, and HER2 status 1. A core needle biopsy is mandatory to ensure a diagnosis of invasive disease and assess biomarkers, and a marker should be placed into the tumor at biopsy to ensure surgical resection of the correct site.

Treatment

Treatment depends on cancer stage and type but typically includes surgery (lumpectomy or mastectomy), radiation therapy, chemotherapy (drugs like doxorubicin, cyclophosphamide, paclitaxel), hormone therapy (tamoxifen, aromatase inhibitors), targeted therapy (trastuzumab for HER2+ cancers), and immunotherapy 1. Standard chemotherapy regimens include AC-T (Adriamycin/Cyclophosphamide followed by Taxol) or TC (Taxotere/Cyclophosphamide), and hormone therapy typically lasts 5-10 years.

Management and Follow-up

Management of breast cancer involves a multidisciplinary team, including a surgeon, radiation oncologist, medical oncologist, radiologist, pathologist, and a breast nurse, and patients should be actively involved in all management decisions 1. Follow-up care includes regular screening, monitoring for recurrence, and addressing any long-term effects of treatment.

Prevention Strategies

Prevention strategies include maintaining a healthy weight, regular exercise, limiting alcohol, avoiding hormone replacement therapy, and considering preventive medications for high-risk individuals 1. Regular screening remains essential for early detection and improved outcomes, with mammography screening in the 50- to 70-year age group reducing breast cancer mortality.

Some key points to consider in the management of breast cancer include:

• The use of predictive biomarkers such as ER, PgR, HER2, and Ki67 to determine treatment choice
• The importance of patient-centered care and involvement in management decisions
• The need for a multidisciplinary team approach to care
• The importance of regular follow-up and monitoring for recurrence
• The consideration of fertility-preservation techniques for younger premenopausal patients
• The use of reliable, patient-centered websites or similar sources of information to support patient education and decision-making.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Etiology of Breast Cancer

• Breast cancer is a complex heterogeneous disease that is categorized into several histological and genomic subtypes with relevant prognostic and therapeutical implications 2
• The molecular hallmarks of breast cancer include immunohistochemical markers (ER, PR, HER2, and proliferation marker protein Ki-67), genomic markers (BRCA1/2 and PIK3CA), and immunomarkers (tumor-infiltrating lymphocytes and PDL1) 3

Diagnosis of Breast Cancer

• Screening for breast cancer is based on patient history, exam, mammography, and ultrasound, with MRI adding additional detection benefit in select patient populations 4
• Sentinel lymph node biopsy continues to be the staging procedure of choice, but data are available that completion axillary dissection for a positive sentinel node may not affect outcomes 4

Treatment of Breast Cancer

• The treatment of breast cancer requires a multidisciplinary approach, taking into account tumor load and molecular markers 5
• For early breast cancer, breast-conserving surgery with radiotherapy or mastectomy alone remains the standard management, with the administration of adjuvant systemic therapy decided by the status of lymph nodes, hormone receptors, and human epidermal growth factor receptor-2 5
• For metastatic breast cancer, the goal of treatments is to prolong survival and maintain quality of life, with standard first-line and follow-up therapy options including targeted approaches such as CDK4/6 inhibitors, PI3K inhibitors, PARP inhibitors, and anti-PDL1 immunotherapy, depending on the tumor type and molecular profile 3

Management of Breast Cancer

• The management of breast cancer is determined in large part by the HER2, HR, ER, and PR status, with about two-thirds of malignancies of the breast being HR-positive/HER2-negative 3
• Endocrine-based therapy is a major treatment option for HR-positive/HER2-negative patients, including selective estrogen receptor modulators (SERMs), selective estrogen-receptor degraders (SERDs), and aromatase inhibitors 3
• Cytotoxic chemotherapeutic agents are used to treat HR-negative breast cancer patients, including taxanes, anthracyclines, anti-metabolites, alkylating agents, and drugs that target microtubules 3