Survival of de novo stage IV breast cancer patients over three decades

Background: De novo stage IV breast cancer patients (BC_IV) depict a clinical picture not influenced by adjuvant therapy. Therefore, the time-dependent impact of changes in diagnostics and treatments on progression and survival can best be evaluated in this subgroup. Methods: BC_IV patients from 1978 to 2013 registered in the Munich Cancer Registry were divided into four periods, and the trends were analysed. Survival was estimated by Kaplan–Meier methods, and prognostic factors were fitted with Cox proportional hazard models. Results: Between 1978 and 2013, 88,759 patients were diagnosed with 92,807 cases of invasive and non-invasive BC. Of these patients, 4756 patients had distant metastases (MET) at diagnosis. The 5-year survival rate improved from 17.4 to 24.7%, while the pattern of metastases did not change. Improved staging diagnostics, a screening programme and primary systemic therapy changed the composition of prognostic strata. Patients with a similar composition as the 1978–1987 cohort exhibited a median survival difference of 13 months; however, neither univariate nor multivariate analysis showed a survival effect for the four periods as a surrogate indicator for changing treatments. HER2+ patients have with 27.6 months a slightly longer survival than all other BC_IV patients. Conclusions: Survival of de novo BC_IV has only modestly improved since the late 1970s, partially masked by changing distributions of prognostic factors due to changes in diagnostics.