Correlation of the tumour-stroma ratio with diffusion weighted MRI in rectal cancer.

OBJECTIVE: This study evaluated the correlation between intratumoural stroma proportion, expressed as tumour-stroma ratio (TSR), and apparent diffusion coefficient (ADC) values in patients with rectal cancer. METHODS: This multicentre retrospective study included all consecutive patients with rectal cancer, diagnostically confirmed by biopsy and MRI. The training cohort (LUMC, Netherlands) included 33 patients and the validation cohort (VHIO, Spain) 69 patients. Two observers measured the mean and minimum ADCs based on single-slice and whole-volume segmentations. The TSR was determined on diagnostic haematoxylin & eosin stained slides of rectal tumour biopsies. The correlation between TSR and ADC was assessed by Spearman correlation (rs). RESULTS: The ADC values between stroma-low and stroma-high tumours were not significantly different. Intra-class correlation (ICC) demonstrated a good level of agreement for the ADC measurements, ranging from 0.84-0.86 for single slice and 0.86-0.90 for the whole-volume protocol. No correlation was observed between the TSR and ADC values, with ADCmeanrs= -0.162 (p= 0.38) and ADCminrs= 0.041 (p= 0.82) for the single-slice and rs= -0.108 (p= 0.55) and rs= 0.019 (p= 0.92) for the whole-volume measurements in the training cohort, respectively. Results from the validation cohort were consistent; ADCmeanrs= -0.022 (p= 0.86) and ADCminrs = 0.049 (p= 0.69) for the single-slice and rs= -0.064 (p= 0.59) and rs= -0.063 (p= 0.61) for the whole-volume measurements. CONCLUSIONS: Reproducibility of ADC values is good. Despite positive reports on the correlation between TSR and ADC values in other tumours, this could not be confirmed for rectal cancer.

The significance of stromal collagen organization in cancer tissue: An in-depth discussion of literature.

It has become clear that carcinogenesis goes beyond tumor cell biology. Cancer research has acknowledged the importance of biological functions of the tumor-microenvironment, wherein not only cellular components seem to hold valuable information but also structural components like collagen fibers. Several studies have focused on the significance of stromal collagen fiber organization and reported on its role in cancer progression, invasiveness and treatment response. In this review, we discuss the different imaging methods for stromal collagen organization, followed by an in-depth discussion of current literature on in-vitro and animal experiments and human studies, highlighting its importance with respect to cancer progression, prognosis and prediction. We can conclude that collagen organization contains valuable information with regard to metastatic potential and clinical outcomes in cancer. However, the significance of an aligned versus disorganized collagen morphology differs between cancer types, implying more research is necessary before steps towards clinical implementation can be made.

Predictive potential of tumour-stroma ratio on benefit from adjuvant bevacizumab in high-risk stage II and stage III colon cancer.

BACKGROUND: The tumour-stroma ratio (TSR) has proven to be an independent prognostic factor in colon cancer. METHODS: Haematoxylin eosin tissue slides of patients from the AVANT trial were microscopically scored for TSR and categorised as stroma -low or stroma -high. Scores were correlated to the primary and secondary endpoint disease-free survival (DFS) and overall survival (OS). RESULTS: Patients with stroma-high tumours (N = 339, 28%) had a significantly shorter DFS (p < 0.001) compared to stroma-low tumours (N = 824, 68%). In the bevacizumab-FOLFOX-4 arm, DFS was significantly shorter compared to FOLFOX-4 in stroma-low tumours, with a hazard ratio (HR) of 1.94 (95% CI 1.24-3.04; p = 0.004). In stroma-high tumours a trend for better DFS was seen in bevacizumab-FOLFOX-4 vs. FOLFOX-4 (HR 0.61 (95% CI 0.35-1.07; p = 0.08)). For bevacizumab-XELOX vs. FOLFOX-4, this was not seen (stroma-low HR 1.07 (95% CI 0.64-1.77; p = 0.80); stroma-high HR 0.78 (95% CI 0.47-1.30; p = 0.35)). OS showed the same pattern for bevacizumab-FOLFOX-4 vs. FOLFOX-4 with a HR of 2.53 (95% CI 1.36-4.71; p = 0.003) for stroma-low and HR 0.50 (95% CI 0.22-1.14; p = 0.10) for stroma-high tumours. For bevacizumab-XELOX vs. FOLFOX-4, HR 1.13 (95% CI 0.55-2.31; p = 0.74) for stroma-low tumours and HR 0.74 (95% CI 0.37-1.51; p = 0.41) for stroma-high tumours. CONCLUSIONS: This exploratory analysis suggests a significantly shorter DFS and OS in stroma-low tumours with addition of bevacizumab to intravenous oxaliplatin-based chemotherapy, contrary to stroma-high tumours, where a beneficial trend is observed.