PhD defence
Tailored to Fit: Balancing Over- and Undertreatment in Early-Stage Triple Negative Breast Cancer Patients
- Y. Wang
- Date
- Tuesday 10 February 2026
- Time
- Location
-
Academy Building
Rapenburg 73
2311 GJ Leiden
Supervisor(s)
- Prof.dr.ir. M.K. Schmidt
Summary
Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer, accounting for about 10–20% of cases and occurring relatively often in younger women. Because TNBC lacks receptors that can be targeted with hormone or HER2 therapies, chemotherapy has long been the main systemic treatment for most patients. However, many people with early-stage TNBC, especially those without lymph-node involvement, may be treated more intensively than necessary. This creates an urgent need for better tools to identify who truly benefits from chemotherapy and who might safely avoid it.
In this thesis, we refined risk classification for early-stage TNBC by studying immune and genetic biomarkers and by improving PREDICT, a widely used tool that estimates breast cancer outcomes. Using a unique Dutch cohort of women who did not receive chemotherapy in routine care, we showed that higher levels of immune cells in and around the tumor—measured as tumor-infiltrating lymphocytes (TILs)—were linked to better long-term survival even without chemotherapy. We also found that without chemotherapy, germline BRCA1 mutation carriers had poorer long-term outcomes and a higher risk of developing second primary cancers, such as cancer in the other breast.
Finally, we integrated TILs into the PREDICT model, improving its ability to distinguish lower-risk from higher-risk TNBC patients and supporting more personalized treatment decisions. These findings help reduce unnecessary treatment and its side effects, while ensuring that patients who need chemotherapy still receive it—an important step toward truly individualized breast cancer care.
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.
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