Elderly women with breast cancer often die due to other causes regardless of primary endocrine therapy or primary surgical therapy.

Survival and cause of death was investigated for Primary Surgical Therapy (PST) and Primary Endocrine Therapy (PET). Of women aged ≥75 years 113 patients received PET, 233 patients underwent PST. PST gave better survival, although this group was younger (p < 0.001). During follow-up the percentage of deaths due to breast cancer was similar and stable in both groups. Increased age was associated with a higher risk on death due to other causes (HR 1.11; CI 1.07-1.14), not on death due to breast cancer (HR 0.94; CI 0.87-1.01). The association of type of treatment and death due to breast cancer was not different between both groups in univariate analyses (HR 0.78; CI 0.44-1.39). In the multivariate model this non-significance remained after correcting for tumor size and age (HR 0.68; CI 0.33-1.42). Treatment should not be based merely on surgical treatment. PET may be an acceptable alternative.