568PFactors of importance in procuring tumoroids from colorectal liver metastasis biopsies for precision medicine

Abstract Background Tumour tissue from individual patients with colorectal cancer may be cultured in vitro as three-dimensional tumoroids that resembles the biological features in vivo including chemotherapy sensitivity and resistance. Tumoroid formation is well-established for resected tumour tissue, but there is a lack of detailed descriptions of cultivating tumoroids from liver biopsies. The purpose of this study was to compare metastasis, imaging, biopsy histology and tumoroid yield. Methods Patients exposed to all standard medical treatment for metastatic colorectal cancer were included within an ongoing phase II clinical trial (NCT03251612). Biopsies from liver were obtained with 16G needles and other localizations 18G. Microscopy was used to evaluate necrosis (present or not) and to quantify the fraction of vital carcinoma cells: 0 (0%), 1 (0-10%), 2 (10-50%) or 3 (50-100%). Tumoroid formation was quantified as 0 (0 tumoroids), 1 (1-10), 2 (10-100), 3 (100-1000) or 4 (>1000). Biopsies of low quality were pooled up to three together for tumoroid formation. Elastography during ultrasound were used to measure the tissue stiffness of a subset of liver metastases and was together with metastasis size other explorative variables. Results A total of 78 biopsies from 27 biopsy sessions were included from liver (22), lung (2), carcinomatosis (1), muscle (1) or kidney (1). No serious adverse events related to biopsy procedures were observed. 37 (49%) of 76 biopsies for histology contained vital carcinoma cells and necrosis was present in 43 (57%). The number of tumoroids after cultivation correlated with the level of vital carcinoma cells in biopsies (p = 0.008) and trend-wise inversely with the stiffness of the tumour (p = 0.05) but not the size of metastasis (p = 0.97) nor presence of necrosis (0.98). Conclusions The tumoroid yield after cultivation of biopsies from chemo-refractory colorectal cancer patients correlates with the level of carcinoma cells determined by microscopy and probably with the stiffness of the metastasis. Necrosis and size of metastasis were not related. These findings may have great implications for selecting and evaluating biopsies for tumoroid formation in precision medicine to colorectal cancer patients. Clinical trial identification NCT03251612. Legal entity responsible for the study The authors. Funding 2cureX. Disclosure L.H. Jensen: Research grant / Funding (institution): MSD; Research grant / Funding (institution): BMS; Research grant / Funding (institution): Incyte; Research grant / Funding (institution): 2cureX. G. Hagel: Shareholder / Stockholder / Stock options, Full / Part-time employment: 2cureX. H. Harling: Advisory / Consultancy: 2cureX. O. Thastrup: Leadership role, Shareholder / Stockholder / Stock options, Full / Part-time employment, Officer / Board of Directors: 2cureX. All other authors have declared no conflicts of interest.