Hyperplasia Breast Cancer Risk May be Revised

Atypical lobular hyperplasia may be as significant a risk factor for breast cancer as atypical ductal hyperplasia

medwireNews: Study findings suggest that atypical lobular hyperplasia (ALH) may be a direct precursor for the development of low-grade ductal breast cancer in situ (DCIS) and thus invasive disease.

The study, published in Cancer Prevention Research, challenges the belief that ALH is only a risk factor for lobular disease, instead comparing the condition to atypical ductal hyperplasia (ADH) which is already considered to be a DCIS precursor.

“Notably, current clinical recommendations are that ADH lesions should be completely excised whereas ALH lesions found on a core may, as risk indicators, not require excision,” explain Lynn Hartmann, from the Mayo Clinic in Rochester, Minnesota, USA, and co-authors.

The team examined data from the Mayo Benign Breast Disease Cohort for 698 women diagnosed with atypical hyperplasia on biopsy between 1967 and 2001, including 330 ADH patients, 327 ALH patients, and 32 women with both diagnoses.

After a mean of 12.5 years of follow-up, 20.4% of the cohort were diagnosed with breast cancer, 19.0% of whom were diagnosed with DCIS and 81.0% with invasive breast cancer.

The ratio of ipsilateral to contralateral breast cancer diagnoses during follow-up was two to one for both ADH and ALH patients, with diagnoses in the first 5 years after biopsy significantly more likely to be in the ipsilateral breast than those diagnosed at a later date (80 vs 62%).

In the ADH patient group, 25% of ipsilateral and contralateral breast cancers were DCIS, while 13% of tumours in ALH patients were DCIS.

Histology revealed that 78% of breast cancers in ADH patients were ductal and 22% lobular or other histology, as were 77% of breast cancers in ALH patients, with 23% lobular or other.

Among 95 women with invasive breast cancers, 75% were node-negative and 25% node-positive. Women with ADH and ALH had a similar risk for node-positive disease and no significant difference in tumour size.

“[T]hese findings underscore the importance of both ADH and ALH as premalignant lesions arising in an altered tissue bed,” Lynn Hartmann and co-authors emphasise.

They conclude: “Both ADH and ALH portend risk for DCIS and invasive breast cancers, predominantly ductal, with two thirds moderate or high grade.

“These longitudinal data can help to inform clinical management strategies.”

Reference

Hartmann L, Radisky D, Frost M, et al. Understanding the Premalignant Potential of Atypical Hyperplasia through Its Natural History: A Longitudinal Cohort Study. Cancer Prevention Research. Published OnlineFirst January 30, 2014. doi: 10.1158/1940-6207.

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