Atypical Ductal Hyperplasia (ADH)

ADH and atypical lobular hyperplasia are now frequently diagnosed with use of core-needle biopsy
Although atypia can be difficult to distinguish from carcinoma in situ:
- Pathologic criteria exist to distinguish the two entities
This distinction is important because, while in situ carcinoma is malignant and may progress to invasive disease:
- ADH is a non-obligate cancer precursor and often represents a marker of an elevated future breast cancer risk
ADH is most frequently found by mammography
Atypia alone, with no other risk factors, confers an approximate:
- Four-fold to five-fold risk of the development of breast cancer
Although breast MRI is more sensitive to detect intermediate- and high-grade ductal carcinoma in situ (DCIS) as well as invasive cancers:
- Breast MRI lacks sufficient diagnostic ability to differentiate ADH versus DCIS or invasive cancers
Excision is indicated for ADH found on core needle biopsy:
- As concomitant in situ or invasive cancer will be found in approximately 15% of cases
The 10-year risk of developing a breast cancer after a diagnosis of ADH:
- Is approximately 17%:
  - Risk is bilateral yet breast cancers developing within 5 years of a biopsy of ADH more likely to occur in the ipsilateral breast than those developing more than 5 years (82% ipsilateral in the first 5 years vs 58% ipsilateral after 5 years)
The National Surgical Adjuvant Breast and Bowel Project (NSABP) P-1 trial:
- Showed that when atypia is found on a sample obtained with needle biopsy and excision rules out cancer:
  - Tamoxifen reduces the risk of developing breast cancer by about 86%:
    - These patients should therefore be referred for discussion about this endocrine prophylaxis
Similarly, the Study of Tamoxifen and Raloxifene (STAR, NSABP P-2) trial:
- Which randomized post-menopausal women to tamoxifen or raloxifene, found that raloxifene provided equivalent risk reduction to tamoxifen with less toxicity (e.g., endometrial cancer)
References:
- Coopey SB, Mazzola E, Buckley JM, et al. The role of chemoprevention in modifying the risk of breast cancer in women with atypical breast lesions. Breast Cancer Res Treat. 2012;136:627-633.
- Heller SL, Moy L. Imaging features and management of high-risk lesions on contrast-enhanced dynamic breast MRI. AJR Am J Roentgenol. 2012;198:249-255.
- Krishnamurthy S, Bevers T, Kuerer H, Yang WT. Multidisciplinary considerations in the management of high-risk breast lesions. AJR Am J Roentgenol. 2012;198:W132-140.
- Hartmann LC, Radisky DC, Frost MH, et al. Understanding the premalignant potential of atypical hyperplasia through its natural history: a longitudinal cohort study. Cancer Prev Res (Phila). 2014;7:211-217.
- Vogel VG, Costantino JP, Wickerham DL, et al; National Surgical Adjuvant Breast and Bowel Project. Update of the National Surgical Adjuvant Breast and Bowel Project Study of Tamoxifen and Raloxifene (STAR) P-2 Trial: Preventing breast cancer. Cancer Prev Res (Phila). 2010;3:696-706.