What is the recommended treatment for atypical ductal hyperplasia of the breast?

Treatment of Atypical Ductal Hyperplasia

All patients with atypical ductal hyperplasia (ADH) diagnosed on core needle biopsy should undergo surgical excision due to a 15-42% risk of upgrade to ductal carcinoma in situ (DCIS) or invasive cancer. 1

Immediate Surgical Management

Surgical excision is mandatory for ADH diagnosed on core needle biopsy because the limited tissue sample may miss concurrent malignancy elsewhere in the lesion. 1 The upgrade rate to DCIS or invasive cancer ranges from 15-42%, making excision the standard of care. 1

Key Points About Excision:

• Core needle biopsy cannot definitively rule out concurrent malignancy that may exist in areas not sampled by the limited cores. 1
• Active surveillance for ADH remains investigational and is not endorsed by the NCCN; surgical excision continues to be the standard of care. 1
• Lumpectomy with tumor-free margins and a rim of grossly normal tissue is the recommended surgical approach. 2

Factors Associated with Higher Upgrade Risk:

• Age >50 years 3
• Presence of a mass lesion on mammography (26% upgrade rate) 3, 4
• ADH involving ≥4 foci on core biopsy (strong predictor of more advanced lesion, p<0.0001) 5
• Pure micropapillary pattern of ADH (all cases showed DCIS on excision) 5

Lower Risk Scenarios:

• Patients ≤50 years old (0% upgrade rate in one study) 3
• Lesions <4 mm in size (0% upgrade) 3
• Focal ADH only (5% upgrade) 3
• ADH limited to ≤2 foci on core biopsy (no worse lesion on excision) 5

Risk Reduction Therapy After Excision

Following surgical excision, tamoxifen should be strongly considered for risk reduction, providing a 75% reduction in invasive breast cancer occurrence in women with ADH (Category 1 evidence). 1

Tamoxifen Protocol:

• Dose: 20 mg daily for 5 years 1
• Women with ADH face a 4- to 5-fold increased risk of developing invasive breast cancer, with continuous annual risk of approximately 0.5-1.0%. 6, 1
• Risk is doubled if the woman has an associated family history of breast cancer. 6

Alternative Risk-Reduction Options:

• For premenopausal women: tamoxifen (20 mg/day for 5 years) or ovarian function ablation combined with tamoxifen 7
• For postmenopausal women: aromatase inhibitors (anastrozole 1 mg daily or letrozole 2.5 mg daily for 5 years) 7
• Do not use aromatase inhibitors alone in premenopausal patients, as no evidence of efficacy is available. 7

Long-Term Surveillance Protocol

All women with ADH require lifelong surveillance regardless of whether they undergo surgery or take tamoxifen. 1

Surveillance Schedule:

• History and physical examination every 6-12 months for 5 years, then annually 1
• Annual diagnostic mammography 1
• For high-risk lesions: clinical examination every 3-6 months for 3 years, then every 6-12 months for 3 years, then annually 7
• Consider more intensive screening in patients with ADH and a family history of breast cancer in a first-degree relative. 1

Natural History Considerations:

• Both ipsilateral and contralateral breasts remain at elevated risk long-term (2:1 ratio of ipsilateral to contralateral breast cancer). 8
• The ipsilateral breast is at especially high risk in the first 5 years after atypia diagnosis, consistent with a precursor phenotype. 8
• Subsequent breast cancers are predominantly invasive ductal cancers (69% moderate or high grade), with 25% node-positive at diagnosis. 8

Common Pitfalls to Avoid

• Never accept discordance between pathology and imaging; this mandates repeat sampling or excision. 2
• Do not rely solely on imaging to determine if a lesion is benign; concordance between pathology, imaging, and clinical findings is crucial. 7
• Geographic correlation between clinical and imaging findings is essential when evaluating suspicious breast lesions. 7
• Do not delay biopsy of a clinically suspicious mass while awaiting imaging; clinical suspicion takes precedence. 2