Macromolecule extravasation-xenograft size matters: a systematic study using probe-based confocal laser endomicroscopy (pCLE).

PURPOSE: Profound changes of the vasculature in tumors critically impact drug delivery and therapy response. We aimed at developing a procedure to monitor morphological and functional parameters of the vasculature in subcutaneous xenograft models commonly applied for therapy testing by using probe-based confocal laser endomicroscopy. PROCEDURES: By monitoring various normal and diseased tissues, we established an experimental and analytical set-up to systematically analyze tracer extravasation from the microvasculature. Application of the approach in two xenograft models (HCT-116 and SW620) was realized consecutively throughout tumor growth. RESULTS: The incidence of dilated vessels increased with xenograft size in both models while macromolecule extravasation and tracer accumulation in the tumor tissue, respectively, was significantly reduced throughout growth. The development of dilated/ultradilated vessels correlated with tracer extravasation only in the HCT-116 but not the SW620 model. The underlying mechanisms are still ambiguous and discussed. CONCLUSIONS: Our findings clearly indicate that both xenograft type and size matter for drug delivery and therapy testing.

Colorectal liver metastases: an update on palliative treatment options.

Only approximately 30% of patients with colorectal cancer liver metastasis qualify for curative therapy, which is in most cases liver lesion resection. Due primarily to the extent of the tumors and patient comorbidities, palliative therapy remains the only option in non-resection cases. Palliation enables local, symptomatic control and prolonged survival in some cases. As established methods are continuously improved, new palliative therapy methods are tested in clinical trials and subsequently introduced into clinical practice. The present review provides an overview of current colorectal liver metastasis treatment when resection is not an option. This review gives the basis for an interdisciplinary decision making process for the treatment of liver metastasis.

Core needle biopsies for determination of the microenvironment in individual tumours for longitudinal radiobiological studies.

PURPOSE: We aimed to establish a core needle biopsy technique to investigate the impact on outcome of irradiation of the microenvironment in individual experimental tumours. METHODS: Nude mice bearing FaDu, UT-SCC-5, UT-SCC-14, and UT-SCC-15 tumours (n=67) were injected with pimonidazole hypoxia and Hoechst 33342 perfusion markers. One core needle biopsy was taken from the central part of the tumour under anaesthesia and the rest of the tumour was excised after marking the position of the needle. Relative hypoxic area (pHF), relative vascular area (RVA), fraction of perfused vessels (PF), and necrotic fraction (NF) were compared in the biopsies and the adjacent whole tumour sections. In a TCD(50) (dose to cure 50% of tumours) assay, 223 UT-SCC-5 tumours were irradiated with 30 fractions over 6weeks either with or without a core biopsy before the start of radiotherapy. RESULTS: The correlations between histological parameters measured in the biopsies and the adjacent tumour sections were dependent on the tumour line. All the four parameters showed weak although significant correlations only in UT-SCC-5. PF was the only parameter which showed a weak but significant correlation in all the four tumour lines. The needle biopsy procedure did not significantly impact on TCD(50) after fractionated irradiation in UT-SCC-5: 98Gy [92; 106] versus 105Gy [96; 117] (p=0.12). pHF, RVA, PF, and NF measured in the pre-treatment biopsy did not predict the outcome of fractionated irradiation within the UT-SCC-5 tumour line. CONCLUSION: A single pre-treatment core needle biopsy may provide valid results for parameters of the tumour micromilieu, however the accuracy is limited by significant intratumoural heterogeneity in the parameters and sampling error. The needle biopsy procedure does not significantly affect local tumour control rates after fractioned irradiation and may therefore be integrated for longitudinal studies in radiobiological experiments. Pre-treatment histological parameters measured in the biopsy did not correlate with the outcome of fractionated irradiation within the UT-SCC-5 tumour line.