Histopathologic indicators of breast cancer biology: insights from population mammographic screening.

Histopathologic features of breast cancer such as tumour size, grade and axillary lymph node (LN) status variably reflect tumour biology and time. Recent evidence suggests that the biological character of breast cancer is established at an early stage and has a major impact on clinical course. The aim of this study was to distinguish the impact of biology on breast cancer histopathology by comparing features of breast cancers diagnosed following population mammographic screening with prevalent vs incident detection and screening interval. Central histopathology review data from 1147 cases of ductal in situ and/or invasive breast cancer were examined. Size, grade and LN status of invasive cancers were positively correlated (P < 0.001). Prevalent invasive cancers were larger (P < 0.001) and more likely to be LN positive (P = 0.02) than incident cases, but grade was not associated with screening episode (P = 0.7). Screening interval for incident cancers was positively associated with invasive cancer size (P = 0.05) and LN status (P = 0.002) but not grade (P = 0.1). Together, these data indicate that biology and time both impact on size and LN status of invasive breast cancer, but grade reflects biology alone. In view of the clinical importance of breast cancer biology, grade as its most direct indicator assumes particular significance.

A simple tool for identifying unaffected women at a moderately increased or potentially high risk of breast cancer based on their family history.

Family history of breast cancer is a more important aspect of clinical management following the discovery of the genes BRCA1 and BRCA2. The authors developed a short questionnaire to categorize risk according to breast cancer history in close relatives. It was completed by 559 women attending for screening mammograms in Sydney, Australia. Twenty-three per cent reported a family history sufficient to be classified at a moderately increased or potentially high risk according to national guidelines (category II or III). Only 29 women (5%) made errors such that their risk category could not be determined. Validation of responses from 89 women, 44 from category II or III, found 100% agreement with classification after interview by a genetic counsellor. This questionnaire has the potential to accurately triage risk based on a woman's knowledge of her family history, and could be used in a variety of settings to identify women who may require further assessment, management and referral advice.