Abstract P3-07-14: Initial treatment and survival among elderly breast cancer patients in the United States by estrogen receptor status and cancer stage at diagnosis: an analysis of national registry data 2000–2009
Authors: Lang K , Huang H , Namjoshi M , Federico V , Menzin J 
Published: August 2014

BACKGROUND: There are few recent studies of initial treatment and survival among elderly, newly diagnosed breast cancer (BC) patients by estrogen receptor (ER) status and cancer stage at diagnosis.

METHODS: The linked Surveillance and Epidemiology End Results-Medicare (SEER-Medicare) database was used for this analysis. SEER is an epidemiologic surveillance system consisting of population-based tumor registries designed to track cancer incidence and survival in geographically defined areas that represent approximately 25% of the US population. The SEER registry file (available through 2007) is linked to Medicare claims and enrollment data available through 2009. We identified female patients newly diagnosed with Stage I, II, III, or IV breast cancer in a SEER registry between January 2002 and December 2007. Study patients were required to be aged 66+ years with no prior history of any other (non-breast) cancer. Patients were followed from the date of breast cancer diagnosis through death or December 31, 2009. Patients were identified as ER+ (ER−) if the ER assay was reported to SEER as positive/elevated (negative/normal). Demographics, initial treatment (surgery or radiation within 4 months of diagnosis), and survival (proportion of patients who died during the study period, survival at 96 months and median survival) were evaluated by ER status and cancer stage. Kaplan-Meier (KM) survival curves were estimated by ER status and stage.

RESULTS: 70,845 female BC patients (59,243 ER+, and 11,602 ER−) were identified. Age at diagnosis was similar for ER+ and ER− patients (mean [SD]: 75–77 [7] years; median: 74–76 years) across all stages. More ER+ patients were White (86% vs. 80% for ER−), and diagnosed at Stage I (56% vs. 39%). Fewer ER+ than ER− patients were diagnosed at Stage II (32% vs. 39%), Stage III (8% vs. 15%) and Stage IV (4% vs. 7%). Most patients had surgery in the first 4 months following diagnosis (96% ER+; 94% ER−), with Stage IV patients least likely (41% ER+ vs. 47% ER−). ER+ patients were more likely to receive initial radiation than ER− patients (48% vs. 42%), with a similar trend by stage (Stage I: 54% vs. 50%; Stage II: 40% vs. 35%; Stage III: 46% vs. 44%; Stage IV: 30% vs. 29%). Fewer ER+ patients died during follow-up (23% vs. 36% of ER− patients). KM survival analyses suggest that survival rates were higher for ER+ than ER− patients for the entire study period, overall (survival at 96 months: 64% vs. 52%), and by stage (Stage I: 73% vs. 70%; Stage II: 60% vs. 50%; Stage III: 38% [median survival 72 months] vs. 27% [median survival 41 months]; Stage IV: 12% [median survival 23 months] vs. 8% [median survival 9 months]).

CONCLUSIONS: Among elderly patients diagnosed with BC, those with ER+ status were diagnosed at earlier stages and had better survival outcomes. Further study of treatment patterns and outcomes by ER status is warranted.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-07-14.