Excellent survival, cancer type, and Nottingham grade after atypical lobular hyperplasia on initial breast biopsy.

Background: Atypical lobular hyperplasia (ALH) is associated with a 10% to 20% risk of subsequent invasive carcinoma, primarily in the ipsilateral breast. Nottingham grading, special tumor types, and survival after invasive cancer diagnosis were analyzed consistently for the first time.

Methods: A longitudinal follow-up study of 252 women who underwent 261 benign surgical biopsies between 1950 and 1985 with a diagnosis of ALH was undertaken. Subsequent invasive breast cancers were graded and subtyped based on histologic features and the cohort assessed for cancer survival.

Results: Forty-eight (19%) women developed invasive breast cancer at an average of 15.1 years. Twenty (42%) of the tumors were special subtype tumors with good prognosis. By an average of 13 years after invasive cancer diagnosis, 2 (10%) of 20 women with special type and variant tumors had died of breast cancer, compared with 9 (32%) of 28 women with tumors of no special type (24 tumors) or an unknown type (4 tumors). Only 1 patient with a tumor of low Nottingham grade died of breast cancer.

Conclusions: ALH is a nonobligate cancer precursor associated with a moderate risk of breast cancer and predicts that later cancers are associated with overall excellent survival. Nearly half of the subsequent cancers show classic or variant patterns of special types with a good prognosis and the majority are of low or intermediate combined histologic grade. Treatment of women with ALH should be influenced by their modest elevation in breast cancer risk and the good prognosis and low mortality of many of these cancers.