The significance of prognostic factors on the occurrence of metastases from breast cancer to various localizations
Zedeler, K.; Keiding, N.; Kamby, C.
Ugeskrift for Laeger 156(1): 42-47
1994
ISSN/ISBN: 0041-5782 PMID: 8291155 Document Number: 435012
The aim of the study was to identify and compare risk factors for development of metastases from breast cancer at specific anatomical sites. The sites were grouped into ten categories, simultaneous occurrences at several sites being common. The influence of various risk factors for recurrence at one specific site can be modelled by well-established survival analysis techniques such as the Cox regression model. Recently, a generalization has been proposed that allows for joint occurrences at more than one site. The prognostic influences of various risk factors on recurrence at different sites may be compared using these models. Both methods were applied to data from the Danish Breast Cancer Cooperative Group on recurrence after breast cancer; the risk factors examined were degree of anaplasia, number of positive lymph nodes, site of primary tumour, skin or deep fascial invasion, age of the patient and adjuvant treatment regimens. Adjuvant therapy had the same effect on recurrence at all sites. For chemotherapy, this effect was marginally significantly positive. The number of positive lymph nodes was associated with an increased risk of metastases at all sites except the brain, where an opposing trend was found. The degree of anaplasia was associated with a somewhat increased risk of metastases at all sites, again the brain was an exception, here the effect of degree of anaplasia was significantly more pronounced. Application of the new types of models resulted in fewer differences between the relative influence of the prognostic factors than are implied by the use of the traditional regression models.