Clinical added value of MRI to CT in patients scheduled for local therapy of colorectal liver metastases (CAMINO): study protocol for an international multicentre prospective diagnostic accuracy study.

BACKGROUND: Abdominal computed tomography (CT) is the standard imaging method for patients with suspected colorectal liver metastases (CRLM) in the diagnostic workup for surgery or thermal ablation. Diffusion-weighted and gadoxetic-acid-enhanced magnetic resonance imaging (MRI) of the liver is increasingly used to improve the detection rate and characterization of liver lesions. MRI is superior in detection and characterization of CRLM as compared to CT. However, it is unknown how MRI actually impacts patient management. The primary aim of the CAMINO study is to evaluate whether MRI has sufficient clinical added value to be routinely added to CT in the staging of CRLM. The secondary objective is to identify subgroups who benefit the most from additional MRI. METHODS: In this international multicentre prospective incremental diagnostic accuracy study, 298 patients with primary or recurrent CRLM scheduled for curative liver resection or thermal ablation based on CT staging will be enrolled from 17 centres across the Netherlands, Belgium, Norway, and Italy. All study participants will undergo CT and diffusion-weighted and gadoxetic-acid enhanced MRI prior to local therapy. The local multidisciplinary team will provide two local therapy plans: first, based on CT-staging and second, based on both CT and MRI. The primary outcome measure is the proportion of clinically significant CRLM (CS-CRLM) detected by MRI not visible on CT. CS-CRLM are defined as liver lesions leading to a change in local therapeutical management. If MRI detects new CRLM in segments which would have been resected in the original operative plan, these are not considered CS-CRLM. It is hypothesized that MRI will lead to the detection of CS-CRLM in ≥10% of patients which is considered the minimal clinically important difference. Furthermore, a prediction model will be developed using multivariable logistic regression modelling to evaluate the predictive value of patient, tumor and procedural variables on finding CS-CRLM on MRI. DISCUSSION: The CAMINO study will clarify the clinical added value of MRI to CT in patients with CRLM scheduled for local therapy. This study will provide the evidence required for the implementation of additional MRI in the routine work-up of patients with primary and recurrent CRLM for local therapy. TRIAL REGISTRATION: The CAMINO study was registered in the Netherlands National Trial Register under number NL8039 on September 20th 2019.

Liver transplantation for unresectable colorectal liver metastases in patients and donors with extended criteria (SECA-II arm D study).

BACKGROUND: Patients with metastatic colorectal cancer receiving palliative chemotherapy have a 5-year survival rate of approximately 10 per cent. Liver transplantation using strict selection criteria in patients with colorectal cancer and unresectable liver-only disease will result in a 5-year survival rate of 56-83 per cent. The aim of this study was to evaluate survival of patients with colorectal liver metastases (CRLM) after liver transplantation using extended criteria for both patients and donors. METHODS: This was a prospective single-arm study. Patients with synchronous unresectable CRLM who were not suitable for arms A, B or C of the SEcondary CAncer (SECA) II study who had undergone radical resection of the primary tumour and received chemotherapy were included; they underwent liver transplantation with extended criteria donor grafts. Patients who had resectable pulmonary metastases were eligible for inclusion. The main exclusion criteria were BMI above 30 kg/m2 and liver metastases larger than 10 cm. Survival was estimated using Kaplan-Meier analysis. RESULTS: Ten patients (median age 54 years; 3 women) were included. They had an extensive liver tumour load with a median of 20 (range 1-45) lesions; the median size of the largest lesion was 59 (range 15-94) mm. Eight patients had (y)pN2 disease, six had poorly differentiated or signet ring cell-differentiated primary tumours, and five had primary tumour in the ascending colon. The median Fong clinical risk score was 3 (range 2-5) and the median Oslo score was 1 (range 1-4). The median plasma carcinoembryonic antigen level was 4·3 (range 2-4346) µg/l. Median disease-free and overall survival was 4 and 18 months respectively. CONCLUSION: Patients with unresectable liver-only CRLM undergoing liver transplantation with extended patient and donor criteria have relatively short overall survival.

ANTECEDENTES: Los pacientes con cáncer colorrectal metastásico (metastatic colorectal c¡ncer, CRC) que reciben quimioterapia paliativa presentan aproximadamente una supervivencia a los 5 años del 10%. El trasplante de hígado utilizando criterios de selección estrictos en pacientes con CRC y enfermedad localizada hepática no resecable presenta una supervivencia a los 5 años del 56-83%. El objetivo de este estudio fue evaluar la supervivencia de pacientes con metástasis hepáticas CRC no resecables (non-resectable CRC liver metastases, CRLM) después del trasplante hepático utilizando criterios extendidos para pacientes y donantes. MÉTODOS: Se ha realizado un estudio prospectivo de un solo brazo. A los pacientes con CRLM sincrónicas no resecables que no eran adecuados para ser incluidos en los brazos A, B o C del estudio SECA-II, con resección quirúrgica radical previa del tumor primario y que recibieron quimioterapia, se les realizó un trasplante de hígado con injerto de donante con criterios extendidos. Los pacientes con metástasis pulmonares resecables también podían ser incluidos. Los principales criterios de exclusión principales fueron el índice de masa corporal > 30 y metástasis hepáticas > 10 cm. La supervivencia se estimó utilizando el método de Kaplan-Meier. RESULTADOS: Diez pacientes (mediana de edad de 54 años, 3 varones) incluidos en el estudio tenían una carga tumoral hepática extensa con una mediana de 20 lesiones (rango 1-45) y un tamaño mediano de la lesión más grande de 59 mm (rango 15-94 mm). Ocho pacientes tenían (y) pN2, seis tenían tumores primarios pobremente diferenciados/células de anillo de sello y cinco tenían tumor primario en colon ascendente. La mediana del Fong Clinical Risk Score fue 3 (rango 2-5). La mediana del Oslo Score fue 1 (rango 1-4). La mediana del nivel de CEA en plasma fue 4 µg/L (rango 2-4346). La mediana de supervivencia libre de enfermedad y supervivencia global fue de 4 y 18 meses, respectivamente. CONCLUSIÓN: Los pacientes con CRLM no resecables localizadas en el hígado que se someten a un trasplante de hígado con criterios extendidos de pacientes y donantes tienen una supervivencia global relativamente corta.

The cloned human 5-HT7 receptor splice variants: a comparative characterization of their pharmacology, function and distribution.

Serotonin (5-hydroxytryptamine, 5-HT) receptor pre-mRNA is alternatively spliced in human tissue to produce three splice variants, h5-HT7(a), h5-HT7(b) and h5-HT7(d), which differ only in their carboxyl terminal tails. Using membranes from transiently and stably transfected HEK293 cells expressing the three recombinant h5-HT7 splice variants we compared their pharmacological profiles and ability to activate adenylyl cyclase. Using PCR on cDNA derived from various human tissues, the 5-HT7(a) and 5-HT7(b) splice variants were detected in every tissue examined. The h5-HT7(d) splice variant was detected in 13 of 16 tissues examined, with predominant expression in the heart, small intestine, colon, ovary and testis. All three h5-HT7 splice variants displayed high affinity binding for [3H]5-HT (pKd=8.8-8.9) in the presence and absence of 100 microM GTP and had similar binding affinities for all 17 ligands evaluated. In HEK293 cells expressing similar, high levels of receptor (approximately 10,000 fmol/mg protein), 5-CT (5-carboxamidotryptamine), 5-MeOT (5-methoxytryptamine) and 5-HT were full agonists while 8-OH-DPAT ((2R)-(+)-8-hydroxy-2-(di-n-propylamino)tetralin) was a partial agonist with relative efficacy of approximately 0.8. Even at this high receptor level, EC50 values for stimulation of adenylyl cyclase were 10- to 50-fold higher than the Kd values, indicating a lack of spare receptors. No significant differences in coupling to adenylyl cyclase were observed between the three splice variants over a wide range of receptor expression levels. For antagonists, binding affinities determined by displacement of [3H]5-HT binding and by competitive inhibition of 5-HT-stimulated adenylyl cyclase activity were essentially identical amongst the splice variants. These studies indicate that the three human splice variants are pharmacologically indistinguishable and that modifications of the carboxyl tail do not influence coupling to adenylyl cyclase.

5HT4(a) and 5-HT4(b) receptors have nearly identical pharmacology and are both expressed in human atrium and ventricle.

5-Hydroxytryptamine (5-HT) increases human heart rate and atrial contractile force and hastens atrial relaxation through 5-HT4 receptors. Moreover, 5-HT may be arrhythmogenic and give rise to atrial fibrillation. It is not clear which splice variant(s) of the 5-HT4 receptor is expressed and mediates these effects of 5-HT in the human heart. Previous studies have indicated different pharmacological properties of 5-HT4 receptors in human heart and mouse colliculi neurones, possibly due to expression of different splice variants. We therefore cloned the human 5-HT4(b) receptor and compared its pharmacological properties with those of the cloned human 5-HT4(a) receptor and searched for the corresponding mRNA in human tissues. The primary structures of the two human 5-HT4 receptor splice variants are identical except for divergent C-terminal tails of 28 and 29 amino acids in the 5-HT4(a) and 5-HT4(b) receptors, respectively. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that both variants were coexpressed in various tissues, including cardiac atrium and ventricle. Additional bands suggested the presence of more than two human 5-HT4 receptor splice variants. With cloned receptors stably expressed in HEK293 cells or transiently expressed in COS-7 cells, [3H]GR 113808 consistently showed slightly higher binding affinity to h5-HT4(b) than to h5-HT4(a) receptor (pKd 0.1-0.2 log units higher). Competition of agonists, partial agonists and antagonists for [3H]GR113808 binding revealed no significant differences between the two receptors. For 5-HT4 receptor agonists and antagonists, their potencies in stimulating or inhibiting, respectively, 5-HT-stimulated adenylyl cyclase activity correlated well with their binding affinities. Tropisetron and SB207710 showed partial agonist activity at high receptor expression levels for both isoforms. Cisapride and renzapride were both partial agonists at moderate receptor levels and full agonists at high receptor levels. Cisapride was more potent than renzapride while the converse was the case in human atrium, for which cisapride had lower affinity and agonist potency than at the recombinant receptors. The binding affinities and agonist potencies of ligands for both 5-HT4(a) and 5-HT4(b) receptors correlated with the corresponding affinities and potencies in human atrium. The agonist potency of SB207710 was around 10 times lower than its binding and blocking affinity for both splice variants, suggesting that activation of adenylyl cyclase and blockade of 5-HT responses are mediated through different conformational states. The similar pharmacological properties of the two human 5-HT4 receptor splice variants together with their expression in human atrium would be consistent with mediation of the cardiostimulant effects of 5-HT through both variants. However, the effects of cisapride appear either mediated through non-a and non-b splice variants of the 5-HT4 receptor or 5-HT4(a) and 5-HT4(b) receptor expression in human atrial cells alters somewhat their pharmacological profile through still unknown mechanisms.