Universiteit Leiden

nl en

PhD defence

Genetic and lifestyle factors in breast cancer prognostication

  • A.G.T. Morra
Tuesday 11 April 2023
Rapenburg 73
2311 GJ Leiden


  • Prof. M.K. Schmidt


Breast cancer is a heterogeneous disease with substantial variability in outcome, risk factors and response to treatment. Therefore, a better understanding of the factors influencing breast cancer outcome could lead to improved prognostication and better stratification of patients into treatment subgroups. To this end, we investigated the association of hereditary genetic variants and non-genetic breast cancer risk factors with breast cancer outcome, and assessed the evidence of potential differential associations across specific tumor subtypes and patient subgroups defined by clinic-pathological variables related to tumor biology and type of systemic treatment. We focused on two breast cancer outcomes, namely survival and risk of developing a second breast cancer in the contralateral breast (contralateral breast cancer).
Based on data from a large international cohort of breast cancer patients, we found clear associations of several known lifestyle breast cancer risk factors with survival (time to death) in breast cancer patients, independently from specific tumor subtype, and of coding hereditary genetic variants in five known breast cancer susceptibility genes with contralateral breast cancer risk. There was also evidence of association of coding hereditary genetic variants in three known breast cancer genes with breast cancer-specific survival (time to death due to breast cancer), although weaker than for contralateral breast cancer risk.  These factors could be incorporated into prediction models for breast cancer outcome thereby potentially improving prognostic estimates and breast cancer counseling. In particular, the findings related to contralateral breast cancer risk are relevant to treatment decisions, follow-up and screening of breast cancer patients.


PhD dissertations

Approximately one week after the defence, PhD dissertations by Leiden PhD students are available digitally through the Leiden Repository, that offers free access to these PhD dissertations. Please note that in some cases a dissertation may be under embargo temporarily and access to its full-text version will only be granted later.

Press enquiries (journalists only)


General information

Beadle's Office
+31 71 527 7211

This website uses cookies.  More information.