PhD Defense: Minimal invasive strategies and quality improvement for colorectal cancer

The implementation of the national bowel screening program in 2014, resulted into a shift towards detection of early stage colorectal cancer (CRC). This has led to new insights in CRC care and development of new minimally invasive treatment modalities. In this thesis, we evaluated the quality of care during several aspects of the CRC care pathway. 

In the first part, we demonstrated that CT colonography as alternative to colonoscopy in faecal immunochemical test (FIT) positive individuals has a low diagnostic yield for the detection of advanced adenomas and leads to detection of (non-relevant) extra-colonic incidental findings.

In the second part, we showed that radiological imaging with CT for detection of synchronous or metachronous distant metastases is unnecessary for low-risk T1 CRC. The low chance of distant metastasis does not outweigh the chance of (non-relevant) incidental findings and costs. Furthermore, we showed limited value of additional CT Colonography staging in case of stenosing CRC.  

In the third part, we described several minimal invasive treatment modalities. We showed that endoscopic mucosal resection (EMR) of large polyps can be performed safely in elderly, ‘colonoscopic assisted laparoscopic wedge resection’ (CAL-WR) is an effective and safe treatment for complex benign colon polyps and that structural response evaluation after neoadjuvant chemoradiation for locally advanced rectal cancer with the option of a watch-and-wait policy has led to a 50% decline of unnecessary surgeries (ypT0N0). Furthermore, we described the results of decompressing colostomy for acute left-sided colorectal obstruction as bridge to definitive surgical resection and the effectiveness of endosponge therapy for anastomotic leakage after rectal surgery.