Omission of surgery in older women with early breast cancer has an adverse impact on breast cancer specific survival

Background: Primary endocrine therapy (PET) is used as an alternative to surgery in up to 40% of UK women with early breast cancer over age 70. This study has investigated the impact of surgery versus PET on breast cancer specific survival (BCSS) in older women. Methods: Cancer registration data were obtained from two English regions from 2002 to 2010 (n=23,961). A retrospective analysis was performed for women with ER positive disease, using statistical modelling to show the effect of treatment (surgery or PET) and age/health status on BCSS. Missing data was handled using multiple imputation. Results: After data pre-processing, 18,730 (78.5%) were identified as having ER positive disease; of these, 10,087 (54%) had surgery and 8,643 (46%) had PET. BCSS was worse in the PET group compared with the surgical group (5 year BCSS: 69% v 90% respectively). This was true for all strata considered, though the differential was lessened in the cohort with the greatest degree of comorbidity. For older, frailer patients the hazard of breast cancer death has less relative impact on overall survival. Selection for surgery on the basis of predicted life expectancy may permit selection of women for whom surgery confers little benefit. This model is being used to develop an on-line algorithm to aid management of older women with early breast cancer (Age Gap Risk Prediction Tool). Conclusion: BCSS in older women with ER positive disease is worse if surgery is omitted. This treatment choice may, therefore, contribute to inferior cancer outcomes