Determinants and prognoses of locoregional and distant progression in breast cancer

Abstract

Purpose: To describe locoregional and distant progression in a population-based breast cancer sample.

Methods and materials: Between 1978 and 1998, the Munich Cancer Registry evaluated 14,429 patients. The mean follow-up of survivors was 8.3 years. Metastases (MET), local recurrence (LR), and lymph node recurrence (LNR) were considered as outcome measures. The prognostic factor for, and effects of, LR and MET were assessed multivariately by the Cox and dynamic Aalen models.

Results: The LR and MET rate increased with increasing tumor size, with the latter described by pT category. Distant MET occurred earlier than local progression. MET was recorded even earlier for MET alone. The mean time from diagnosis to MET for MET and LR was 54.9, 43.4, 29.4, and 24.7 months and for MET only was 36.5, 31.0, 22.6, and 12.9 months for pT1, pT2, pT3, and pT4, respectively. After MET, survival varied only slightly by pT stage; after LR, a more favorable prognosis, especially for pT1 and pT2, was evident. The prognosis after MET depended mainly on the MET location; 50% of patients with cerebral or nervous system MET survived <1 year and 50% of those with skeletal MET survived >2 years. In the Cox model, the relative risk of LR for MET was 3.0. In the Aalen model, after 30 months, when the hazard rates of MET began to decline, there was still an excess risk of MET after LR.

Conclusion: This disease description highlights the importance of long-term observational studies. Empiric evidence that LR is both an indicator for, and in part a cause of, MET has been provided. In the future, the MET location should be reported. Variations in guidelines or health care systems that influence the time to MET and survival after MET through different diagnostic procedures should also be considered.