Mammography-detected breast cancer over time among patients age 75 and older at a community-based cancer center: 1990-2008.

Abstract

9086 Background: In 2009 the US Preventive Services Task Force reported insufficient current evidence to assess additional benefits and harms of screening mammography for women age 75+. Our aim is to evaluate mammography detected breast cancer characteristics and outcomes in this oldest age group. Methods: We conducted a prospective cohort study of all women presenting with primary breast cancer (BC), aged 50-75+, biopsy confirmed Stage 0-IV, 1990-2008, identified and tracked in our registry database (n=5,595). Clinical presentation characteristics including age, AJCC 6 TNM stage, and method of detection by patient (PtD), physician (PhysD) or mammography (MgD) were chart abstracted at time of diagnosis. Cases with unknown or other method of detection (n=89) were excluded. The Kaplan Meier method was used to compare disease specific survival (DSS) rates. Results: Women age 75+ comprised 17% of our cohort (n=950), mean age 79.77, range 75-94 with 63% MgD (n=596), 29% PtD (n=273), and 9% PhysD (n=81). Among patients age 75+, percent mammography detected BC averaged 52% from 1990-1998 and averaged 68% from 1999-2008 with a concurrent decline in PtD and PhysD BC over time (Pearson Chi-Square = 29.97, p <.001). Overall, 17% of MgD breast cancers were stage 0 and 62% were stage I with 3-4% stage 0 and 32-35% stage I among PtD and PhysD BCs (Pearson Chi-Square = 226.28, p<.001). Percentage stage 0 cases decreased with increasing age at diagnosis for MgD BC; age 50-59 = 25%, age 60-69 = 21%, age 70-74 = 14% and age 75+ = 17%. Percentage MgD stage I BC increased with age; age 50-59 = 50%, age 60-69 = 57%, age 70-74 = 61% and age 75+ = 62% (Pearson chi square 49.78, p<.001). 75+ MgD 5 year DSS was 98% with the 10 year rate = 92% compared to PtD 5 year DSS = 87% and 10 year DSS = 80% (log rank test = 20.95, p<.001). Conclusions: At our institution, the majority of breast cancer in women age 75+ is currently mammography detected with a lower rate of stage 0 disease and higher rate of stage I disease than women age 50-69. MgD BC in women 75+ presents primarily with disease treatable with options well tolerated by older adults and exhibits a low rate of DSS mortality.