Circulating cell-free DNA as a biomarker in the diagnosis and prognosis of colorectal cancer

Colorectal cancer (CRC) is a disease without evident clinical symptoms in early stages, leading to late diagnosis and disease management. Current diagnostic and prognostic tools require invasive procedures and circulating molecular biomarkers fail to have optimal sensitivity and specificity. Circulating biomarkers with high clinical performance may be valuable for early diagnosis and prognosis of CRC. The purpose of this review was to investigate the application of circulating cell-free DNA (ccfDNA) in CRC diagnosis and prognosis and the analytical methods used in blood samples in articles published between 2005 and 2016. Based on specific inclusion and exclusion criteria, 26 articles were selected. Most studies used ccfDNA quantification as the molecular biomarker. The analytical method was mainly based on the quantitative polymerase chain reaction (qPCR). Biomarkers based on aberrantly methylated genes (n=6) and ccfDNA integrity/fragmentation (n=2) were also used for the CRC diagnosis. The CRC prognosis used the detection of oncogene mutations, such as KRAS and BRAF, in ccfDNA. Significant differences were found in variables among the studies revealing potential bias. ccfDNA quantification as a diagnostic biomarker for CRC has promising results but it lacks clinical specificity since other diseases present a similar increase in ccfDNA content. However, increasing research in the epigenomic field can lead the way to a clinically specific biomarker for the CRC early diagnosis. As for the analytical method, qPCR and derivatives seem to be a perfectly valid technique. The use of ccfDNA quantification in CRC prognosis seems promising. The attempt to use the ccfDNA quantification in clinical practice may reside in the prognosis using a qPCR technique

Assessment of circulating DNA in the diagnosis of recurrence in colorectal cancer: systematic review and meta-analysis

O câncer colorretal (CCR) tem altas taxas de incidência e de mortalidade. Seu diagnóstico hoje se baseia em exames de imagem e na dosagem sérica do antígeno carcinoembriogênico (CEA). O último de baixa sensibilidade e especificidade na detecção de recorrências. Entre biomarcadores periféricos em estudo destaca-se o DNA circulante (cDNA). Aqui avaliamos a acurácia da quantificação do cDNA na detecção de recorrência em pacientes com CCR. Uma revisão sistemática foi conduzida com estudos publicados até janeiro de 2022. Dados foram coletados permitindo agregar a sensibilidade (S), especificidade (E) e razão de chances diagnósticas (DOR), assim como apresentar uma curva ROC sumária (sROC) para os estudos incluídos. Foram incluídos 127 estudos para a etapa qualitativa que mostraram dois principais biomarcadores de cDNA: a quantificação total de DNA (cfDNA) e a quantificação de mutações alvo (ctDNA). Desses, 59 foram incluídos na meta-análise e apresentaram S = 62,7% (IC95% 54,9 69,8), E = 81,6% (IC95% 75,1 86,7) e DOR = foi de 7,427 (IC95% 5,052 10,917). A melhor performance diagnóstica foi encontrada no subgrupo de estudos ctDNA, que incluíram pacientes não metastáticos S = 69,1% (IC95% 52,9 81,7), E = 88,1% (IC95% 81,4 97,7) e DOR = 16,63 (IC95% 8,557 32,319). Biomarcadores, que quantificam mutações relacionadas a doença (e.g KRAS, BRAF, PIK3CA), demonstram um melhor poder na identificação de recorrências. Apesar da performance aceitável do cDNA, a partir das evidências disponíveis, não foi possível demonstrar uma performance diagnóstica melhor ou comparável àquela da dosagem do CEA (> 5ug/ml) na detecção de recorrência do câncer colorretal.Colorectal cancer (CRC) has high incidence and mortality rates. Its diagnosis is currently based on imaging tests and serum levels of carcinoembryogenic antigen (CEA). The latter of low sensitivity and specificity in detecting recurrences. Among the peripheral biomarkers being studied, circulating DNA (cDNA) stands out. Here we evaluated the accuracy of cDNA quantification in detecting recurrence in patients with CRC. A systematic review was conducted with studies published up to January 2022. Data were collected, allowing the aggregation of sensitivity (S), specificity (E) and diagnostic odds ratio (DOR), as well as presenting a summary ROC curve (sROC) for the studies. included. 127 studies were included for the qualitative stage that showed two main cDNA biomarkers: total DNA quantification (cfDNA) and quantification of target mutations (ctDNA). Of these, 59 were included in the meta-analysis and presented S = 62.7% (95%CI 54.9 69.8), E = 81.6% (95%CI 75.1 86.7) and DOR = was 7.427 (95%CI 5.052 - 10.917). The best diagnostic performance was found in the subgroup of ctDNA studies that included non-metastatic patients S = 69.1% (95%CI 52.9 81.7), E = 88.1% (95%CI 81.4 97.7) and DOR = 16.63 (95%CI 8.557 32.319). Biomarkers that quantify disease-related mutations (e.g. KRAS, BRAF, PIK3CA) demonstrate better power in identifying recurrences. Despite the acceptable performance of the cDNA, based on the available evidence, it was not possible to demonstrate a better or comparable diagnostic performance to that of the CEA dosage (> 5ug/ml) in the detection of CRC recurrence

Circulating cell-free DNA as a biomarker in the diagnosis and prognosis of colorectal cancer

Abstract Colorectal cancer (CRC) is a disease without evident clinical symptoms in early stages, leading to late diagnosis and disease management. Current diagnostic and prognostic tools require invasive procedures and circulating molecular biomarkers fail to have optimal sensitivity and specificity. Circulating biomarkers with high clinical performance may be valuable for early diagnosis and prognosis of CRC. The purpose of this review was to investigate the application of circulating cell-free DNA (ccfDNA) in CRC diagnosis and prognosis and the analytical methods used in blood samples in articles published between 2005 and 2016. Based on specific inclusion and exclusion criteria, 26 articles were selected. Most studies used ccfDNA quantification as the molecular biomarker. The analytical method was mainly based on the quantitative polymerase chain reaction (qPCR). Biomarkers based on aberrantly methylated genes (n=6) and ccfDNA integrity/fragmentation (n=2) were also used for the CRC diagnosis. The CRC prognosis used the detection of oncogene mutations, such as KRAS and BRAF, in ccfDNA. Significant differences were found in variables among the studies revealing potential bias. ccfDNA quantification as a diagnostic biomarker for CRC has promising results but it lacks clinical specificity since other diseases present a similar increase in ccfDNA content. However, increasing research in the epigenomic field can lead the way to a clinically specific biomarker for the CRC early diagnosis. As for the analytical method, qPCR and derivatives seem to be a perfectly valid technique. The use of ccfDNA quantification in CRC prognosis seems promising. The attempt to use the ccfDNA quantification in clinical practice may reside in the prognosis using a qPCR technique