What are the latest guidelines for breast cancer treatment?

Latest Breast Cancer Guidelines

The most current breast cancer treatment guidelines recommend a multidisciplinary approach based on molecular subtypes, with treatment decisions guided by tumor characteristics including hormone receptor status, HER2 status, and stage of disease. 1

Breast Cancer Screening

• Annual or biennial mammography is recommended for women aged 50-69 years (Level of Evidence I, Grade A) 1
• For women aged 40-49 and 70-74 years, regular mammography may be performed, though evidence for benefit is less established (Level of Evidence II, Grade B) 1
• Women with strong family history of breast cancer or BRCA mutations should undergo annual MRI alternating with mammography/ultrasound every 6 months (Level of Evidence III, Grade A) 1

Diagnosis and Pathology

• Breast imaging should include bilateral mammogram and ultrasound of breasts and axillae (Level of Evidence I, Grade A) 1
• MRI is recommended when standard imaging is inconclusive or in special clinical situations (Level of Evidence I, Grade A) 1
• Pathological evaluation must include histology from the primary tumor and cytology/histology of axillary nodes if involvement is suspected 1
• Pathology reports should include histological type, grade, and immunohistochemical evaluation of ER, PR, HER2, and proliferation markers like Ki67 1
• Tumors should be categorized into surrogate intrinsic subtypes based on routine histology and immunohistochemistry 1
• Genetic counseling and testing for BRCA1/2 mutations should be offered to high-risk patients 1

Staging and Risk Assessment

• Disease staging should follow the TNM system with documentation of hormone receptor status 1
• Routine staging includes complete blood counts, chemistry panel, chest X-ray, and contralateral mammography 1
• Additional imaging (bone scan, abdominal ultrasound/CT) should be performed only if clinically indicated by symptoms or laboratory findings 1

Treatment Approaches by Subtype

Early Breast Cancer (Stage I-III)

Hormone Receptor-Positive/HER2-Negative (70% of patients)

• Endocrine therapy is the cornerstone of treatment, with 5-10 years of therapy recommended 2
• CDK4/6 inhibitors combined with endocrine therapy have shown significant progression-free survival benefits and are recommended for appropriate patients 1
• Sequential monotherapy is preferred over combination chemotherapy for advanced disease unless there is rapid clinical progression or life-threatening visceral metastases 1

HER2-Positive (15-20% of patients)

• Anti-HER2 targeted therapy combined with chemotherapy is standard of care 2
• For advanced HER2+ disease, trastuzumab with vinorelbine or a taxane is preferred for first-line therapy 1
• Dual HER2 blockade with trastuzumab and pertuzumab can be combined with docetaxel, weekly paclitaxel, vinorelbine, or nab-paclitaxel 1

Triple-Negative (15% of patients)

• Chemotherapy remains the primary systemic treatment option 1
• For previously treated patients with anthracyclines with/without taxanes, carboplatin has shown comparable efficacy with a more favorable toxicity profile compared to docetaxel 1
• Immunotherapy has recently been incorporated into treatment regimens for some triple-negative breast cancers 2

Surgical Approaches

• For early-stage disease, options include breast-conserving surgery (lumpectomy) with radiation or mastectomy 3
• Sentinel lymph node biopsy is the preferred method for axillary staging in clinically node-negative patients 1
• For patients with 1-2 positive sentinel nodes undergoing breast conservation with whole-breast radiation, completion axillary lymph node dissection may be avoided (based on ACOSOG Z0011 criteria) 1

Radiation Therapy

• Whole breast radiation is recommended after breast-conserving surgery (Category 1) 1
• For patients with ≥4 positive nodes, radiation to the chest wall, infraclavicular region, supraclavicular area, and internal mammary nodes is recommended (Category 1) 1
• For patients with 1-3 positive nodes, radiation to these regions should be strongly considered 1
• Women aged 70+ with ER-positive, clinically node-negative early breast cancer may omit radiation after lumpectomy if receiving endocrine therapy 1

Systemic Therapy for Advanced Disease

• For HR-positive/HER2-negative advanced disease, endocrine therapy partnered with targeted agents (CDK4/6 inhibitors, mTOR inhibitors, PI3K inhibitors) is preferred over chemotherapy 1
• For triple-negative advanced breast cancer, there are no specific chemotherapy recommendations different from other HER2-negative disease 1
• Metastatic breast cancer is treated according to subtype with goals of prolonging life and palliating symptoms 3

Special Considerations

• For patients with BRCA mutations, PARP inhibitors have shown efficacy 2
• Preoperative (neoadjuvant) therapy is becoming standard for most early-stage HER2-positive and triple-negative breast cancers 2
• Postmenopausal women should be offered bisphosphonates as part of adjuvant therapy 4

Follow-up Recommendations

• History and physical examination every 3-6 months for 3 years, then every 6-12 months thereafter 1
• Tumor markers may be used to evaluate response to treatment in patients with non-measurable metastatic disease, but should not be used alone to initiate treatment changes 1
• Evaluation of response to therapy should generally occur every 2-4 months for endocrine therapy or after 2-4 cycles of chemotherapy 1

The latest NCCN Guidelines (2024) emphasize a personalized approach to breast cancer treatment with continued focus on molecular subtypes to guide therapy decisions and improve outcomes 1.