Abstract P3-10-31: Epithelial Proliferation (Ki67) Is Not an Independent Variable for Breast Cancer Relapse in Symptomatic or Screen Detected Breast Cancers (SDBC)

Abstract

Background: UK screen detected breast cancers (SDBC) (aged 50-65 years) have an overall 97.2% 5 year relative survival compared to 77.6% for symptomatic cancers. Epithelial proliferation has been used to determine therapy in the St. Gallen guidelines (Ki67 ≥30% indicates the need for chemotherapy). Methods: To determine the value of Ki67 in post-menopausal breast cancer in women aged 50-65 years, we have studied Ki67 in 1270 women aged 50-65 years (mean 57 years) with either symptomatic cancers (n=412) or SDBC (n=858) with a 10 year follow up. Results: Ki67 predicted relapse and death in both symptomatic and SDBC. Mode of detection, size, grade, node status and oestrogen receptor (ER) were independently predictive of breast cancer mortality and Ki67 was not an independent variable. In small size ≤15mm ER positive SDBC (n=248) or symptomatic cancers (n=146), Ki67 was not prognostic (p=0.13 and 0.59 respectively). Twelve per cent of symptomatic and 2% of SDBC had died within 5 years. Mean Ki67 in SDBC was 21.4 (SD 10.3) and 34.2 (SD 16.2) in symptomatic cancers (p=≤0.001). ER positive cancers had lower Ki67 levels (p=0.002). For each 10 unit increase in Ki67, increases in distant relapse occurred (RR 1.43:95%CI;1.32-1.55). Ten Year Survival According to Ki67 and Mode of Presentation Discussion: Epithelial proliferation is prognostic in breast cancer but its value is predominantly in large size (≥15mm) symptomatic tumours and Ki67 alone cannot be used to determine therapy. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-10-31.