This thesis consists of two sections. In Section I, (pre)clinical research investigating novel targets for pre- and intraoperative molecular imaging of pancreatic cancer are discussed. In Section... Show moreThis thesis consists of two sections. In Section I, (pre)clinical research investigating novel targets for pre- and intraoperative molecular imaging of pancreatic cancer are discussed. In Section II, various studies are described which lay the groundwork for further investigation into response monitoring and prediction in rectal cancer using various imaging modalities. Show less
There is a lack of knowledge regarding the definition, classification and appropriate treatment of malignant lateral lymph nodes in patients with (locally advanced) rectal cancer. This thesis aimed... Show moreThere is a lack of knowledge regarding the definition, classification and appropriate treatment of malignant lateral lymph nodes in patients with (locally advanced) rectal cancer. This thesis aimed to increase this knowledge and improve treatment practices for this population. Show less
Newly introduced hybrid systems that combine an MRI scanner with a linear accelerator for radiation treatment, called MR-linacs, provide an opportunity for the daily acquisition of quantitative MRI... Show moreNewly introduced hybrid systems that combine an MRI scanner with a linear accelerator for radiation treatment, called MR-linacs, provide an opportunity for the daily acquisition of quantitative MRI (qMRI) without increasing patient burden. This allows for the measurement of changes in quantitative MRI biomarkers over time, that may indicate a response to the radiation treatment. In this thesis, the performance of the Unity MR-linac with regards to several qMRI sequences was characterized, showing results similar to diagnostic systems in terms of accuracy and repeatability. Additionally, we found changes in qMRI parameters in patients early during treatment, which indicates potential as biomarkers for treatment outcome. Show less
Survival of patients with colorectal cancer improved markedly over the past decades, as a result of advances in screening, staging procedures, treatment, and surveillance. However, still about 20%... Show moreSurvival of patients with colorectal cancer improved markedly over the past decades, as a result of advances in screening, staging procedures, treatment, and surveillance. However, still about 20% of patients with colorectal cancer develop metachronous metastases and 20% of all patients with colorectal cancer have metastatic disease at diagnosis. Several treatment modalities, such as total mesorectal excision (TME) and preoperative (chemo)radiotherapy for rectal cancer, as well as adjuvant chemotherapy for stage III colon cancer, have been studied extensively and showed to improve cancer-related outcomes. On the contrary, the effectiveness of other treatment modalities including adjuvant chemotherapy for rectal cancer and for stage II colon cancer, and surgery of the primary tumour in incurable metastatic colorectal cancer are still subject of debate. Moreover, there is considerable short-term and long-term morbidity after (chemo)radiotherapy or surgery which should be taken into account. Further defining optimal treatment strategies is therefore of great importance. This thesis focused on improving evidence for treatment modalities that are currently subject of debate for patients with colorectal cancer. This was done using data from randomised controlled trials as well as cancer registry data. Show less
This thesis describes the use of high-dose-rate endorectal brachytherapy as a boost to external beam radiotherapy in patients with rectal cancer. With 60% clinical complete response in the HERBERT... Show moreThis thesis describes the use of high-dose-rate endorectal brachytherapy as a boost to external beam radiotherapy in patients with rectal cancer. With 60% clinical complete response in the HERBERT study, this treatment is very promising for use in organ preservation studies. Both toxicity of external beam radiotherapy as toxicity of brachytherapy are addressed and further improvements to the brachytherapy technique are suggested to increase tumor control while limiting toxicity. Show less
By implementation of MRI-based staging, selective preoperative radiotherapy and surgical resection according to the TME-principle, the outcomes for patients with locally advanced rectal cancer have... Show moreBy implementation of MRI-based staging, selective preoperative radiotherapy and surgical resection according to the TME-principle, the outcomes for patients with locally advanced rectal cancer have improved considerably over the last decades. This has led to an increased focus on quality of life, functional outcomes and shared decision making. In this thesis, novel treatment options for patients with locally advanced rectal cancer are evaluated, including watch and wait for patients with a complete response after chemoradiotherapy as well as a total neoadjudant therapy (TNT) approach. Also quality of life and the importance patients assign to several outcome measures after ungoqing treatment for rectal cancer themselves are described. Show less
This thesis shows that quality of colorectal cancer care is irrevocably associated with hospital costs. Although surgical auditing is a cost and time-consuming exercise, it has a strong potential... Show moreThis thesis shows that quality of colorectal cancer care is irrevocably associated with hospital costs. Although surgical auditing is a cost and time-consuming exercise, it has a strong potential to improve outcomes in healthcare and simultaneously reduce hospital costs. Comparing hospital performances on both quality and costs makes identification of ‘best practice’ hospitals possible. Moreover, providing combined quality-cost outcomes of frail patients or operation techniques provides valuable insights where to start quality improvement initiatives. Finally, rewarding healthcare providers based on operative risk could be a first step in developing powerful reimbursement systems. This all might catalyze the continuous improvement of value leading to a more sustainable healthcare system in the future. Show less
In this thesis long-term effects and quality of life after treatment for rectal cancer are evaluated. Long-term data were assessed from the TME trial. In this trial 1530 Dutch patients with... Show moreIn this thesis long-term effects and quality of life after treatment for rectal cancer are evaluated. Long-term data were assessed from the TME trial. In this trial 1530 Dutch patients with rectal cancer were included between 1996 and 1999. These patients were randomly assigned to total mesorectal excision (TME) or to short-course preoperative radiotherapy (5x5 Gy) followed by TME surgery. Show less
