Background: De novo stage IV breast cancer patients (BCIV) 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: BCIV 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 BCIV patients.
Conclusions: Survival of de novo BCIV has only modestly improved since the late 1970s, partially masked by changing distributions of prognostic factors due to changes in diagnostics.
Keywords: Breast cancer; Metastasis organs; Stage IV; Survival; Trends.