This thesis highlights, firstly, the importance of early CRC detection by presenting results of a CRC diagnostic proteomic biomarker signature with high discriminative power. Secondly, a strong... Show moreThis thesis highlights, firstly, the importance of early CRC detection by presenting results of a CRC diagnostic proteomic biomarker signature with high discriminative power. Secondly, a strong robust, independent prognostic tumor stroma ratio (TSR) biomarker, which confirms to be of important clinical value. The TSR has the ability to stratify colon cancer patients according to their prognostic outcome in a highly reproducible and low-cost manner. It has shown to link patients with a high intra tumor stromal content and a worse prognosis. Literature shows a wealth of evidence that supports this prognostic value in CRC as well as in other cancers. This PhD research therefore concludes that it should be implemented in the official guidelines of the TNM classification to improve stratification for CRC patients in daily routine pathological evaluation. The prospective, international, multicentre UNITED study will hopefully overcome the last hurdle for this clinical implementation. Lastly, this thesis offers more insight in the elusiveness of the tumor microenvironment and stromatogenesis that contributes to the aggressiveness of some CRC tumors. The biological differences, interconnections and changes in the microenvironment presented give multiple leads for further research and new personalized treatment possibilities. Show less
Background. The time interval between CRT and surgery in rectal cancer patients is still the subject of debate. The aim of this study was to first evaluate the nationwide use of restaging magnetic... Show moreBackground. The time interval between CRT and surgery in rectal cancer patients is still the subject of debate. The aim of this study was to first evaluate the nationwide use of restaging magnetic resonance imaging (MRI) and its impact on timing of surgery, and, second, to evaluate the impact of timing of surgery after chemoradiotherapy (CRT) on short- and long-term outcomes.Methods. Patients were selected from a collaborative rectal cancer research project including 71 Dutch centres, and were subdivided into two groups according to time interval from the start of preoperative CRT to surgery (< 14 and ae14 weeks).Results. From 2095 registered patients, 475 patients received preoperative CRT. MRI restaging was performed in 79.4% of patients, with a median CRT-MRI interval of 10 weeks (interquartile range [IQR] 8-11) and a median MRI-surgery interval of 4 weeks (IQR 2-5). The CRT-surgery interval groups consisted of 224 (< 14 weeks) and 251 patients (>= 14 weeks), and the long-interval group included a higher proportion of cT4 stage and multivisceral resection patients. Pathological complete response rate (n = 34 [15.2%] vs. n = 47 [18.7%], p = 0.305) and CRM involvement (9.7% vs. 15.9%, p = 0.145) did not significantly differ. Thirty-day surgical complications were similar (20.1% vs. 23.1%, p = 0.943), however no significant differences were found for local and distant recurrence rates, disease-free survival, and overall survival.Conclusions. These real-life data, reflecting routine daily practice in The Netherlands, showed substantial variability in the use and timing of restaging MRI after preoperative CRT for rectal cancer, as well as time interval to surgery. Surgery before or after 14 weeks from the start of CRT resulted in similar short- and long-term outcomes. Show less
Aim A Snapshot study design eliminates changes in treatment and outcome over time. This population based Snapshot study aimed to determine current practice and outcome of rectal cancer treatment... Show moreAim A Snapshot study design eliminates changes in treatment and outcome over time. This population based Snapshot study aimed to determine current practice and outcome of rectal cancer treatment with published landmark randomized controlled trials as a benchmark.Method In this collaborative research project, the dataset of the Dutch Surgical Colorectal Audit was extended with additional treatment and long-term outcome data. All registered patients who underwent resection for rectal cancer in 2011 were eligible. Baseline characteristics and outcome were evaluated against the results of the Dutch TME trial and the COLOR II trial from which the original datasets were obtained.Results A total of 71 hospitals participated, and data were completed for 2102 out of the potential 2633 patients (79.8%). Median follow-up was 41 (interquartile range 25-47) months. Overall circumferential resection margin (CRM) involvement was 9.3% in the Snapshot cohort and 18.5% in the Dutch TME trial. CRM positivity after laparoscopic resection was 7.8% in the Snapshot and 9.5% in the COLOR II trial. Three-year overall local recurrence rate in the Snapshot was 5.9%, with a disease-free survival of 67.1% and overall survival of 79.5%. Benchmarking with the randomized controlled trials revealed an overall favourable long-term outcome of the Snapshot cohort.Conclusion This study showed that current rectal cancer care in a large unselected Dutch population is of high quality, with less positive CRM since the TME trial and oncologically safe implementation of minimally invasive surgery after the COLOR II trial. Show less
BACKGROUND The intra-tumor stroma percentage in colon cancer (CC) patients has previously been reported by our group as a strong independent prognostic parameter. Patients with a high stroma... Show moreBACKGROUND The intra-tumor stroma percentage in colon cancer (CC) patients has previously been reported by our group as a strong independent prognostic parameter. Patients with a high stroma percentage within the primary tumor have a poor prognosis. PATIENTS AND METHODS Tissue samples from the most invasive part of the primary tumor of 710 patients (52% Stage II, 48% Stage III) participating in the VICTOR trial were analyzed for their tumor-stroma percentage. Stroma-high (>50%) and stroma-low (≤50%) groups were evaluated with respect to survival times. RESULTS Overall and disease-free survival times (OS and DFS) were significantly lower in the stroma-high group (OS P<0.0001, hazard ratio (HR)=1.96; DFS P<0.0001, HR=2.15). The 5-year OS was 69.0% versus 83.4% and DFS 58.6% versus 77.3% for stroma-high versus stroma-low patients. CONCLUSION This study confirms the intra-tumor stroma ratio as a prognostic factor. This parameter could be a valuable and low cost addition to the TNM status and next to current high-risk parameters such as microsatellite instability status used in routine pathology reporting. When adding the stroma-parameter to the ASCO criteria, the rate of 'undertreated' patients dropped from 5.9% to 4.3%, the 'overtreated' increased with 6.8% but the correctly classified increased with an additional 14%. Show less
