PhD defence D. M. (David) Mens

Below is a brief summary of the dissertation:

The treatment of rectal cancer has improved considerably over recent decades, resulting in better survival. However, treatments such as (chemo)radiotherapy and surgery can also have a lasting impact on patients’ quality of life. Moreover, not every patient requires the same treatment. This thesis therefore focuses on a more personalized approach to rectal cancer care: providing the right treatment to the right patient, as intensive as necessary and as limited as possible.

Several studies investigated whether new techniques are able to help predict which patients are most likely to benefit from specific treatments. These include analysing tumor-related DNA in the blood and using artificial intelligence to predict tumour response on chemoradiotherapy. In addition, this thesis examines how different treatment strategies affect patients’ health-related quality of life after surgery.

Another important focus is whether major surgery can safely be avoided. In patients whose tumour completely disappears after (chemo)radiotherapy, intensive surveillance may sometimes replace surgery. Nationwide research shows how this “watch-and-wait” strategy is being implemented in clinical practice. Finally, this thesis demonstrates that factors such as sex and the characteristics of recurrent disease may also be relevant when making treatment decisions.

Together, these studies support a shift towards more personalized rectal cancer care, in which treatment decisions consider not only survival, but also quality of life and individual patient preferences.