Cell-free DNA in healthy individuals, noncancerous disease and strong prognostic value in colorectal cancer

Abstract

The purpose was to investigate total cell-free DNA (cfDNA) in colorectal cancer (CRC) patients during treatment with secondline chemotherapy and in healthy controls and patients with different comorbidities. Patient treated with second-line irinotecan for metastatic CRC (n 5 100), a cohort of healthy controls with and without comorbidity (n 5 70 and 100, respectively) were included. cfDNA was quantified by an in-house developed quantitative polymerase chain reaction from plasma samples drawn prior to the first cycle of chemotherapy and at time of progression. cfDNA levels were significantly higher in CRC compared to controls, with a clear capability for discriminating between the groups (receiver operation curve analysis; area under the curve 0.82, p < 0.0001). Patients with high levels had a shorter survival from irinotecan compared to those with lover levels. The cohort independent upper normal limit divided patients into high and low risk groups. The progression-free survival (PFS) was 2.1 months [95% confidence interval (CI) 2.0-3.4] and 6.5 (95% CI 4.2-7.2) months [hazard ratio (HR) 2.53; 95% CI 1.57-4.06, p < 0.0001] and overall survival (OS) 7.4 months (95% CI 4.3-8.7) and 13.8 months (95% CI 11.9-18.9; HR 2.52; 95% CI 1.54-4.13, p < 0.0000), respectively. Cox regression multivariate analysis showed a PFS HR of 1.4 (95% CI 1.1-1.7) for each increase in cfDNA quartile, p 5 0.03 and 1.6 (1.3-2.0) for OS, p < 0.0001, respectively. A combined marker analysis with plasma KRAS mutations added further prognostic impact, which was consistent when performed on the samples drawn at time of progression. In conclusion, cfDNA measurement holds important clinical information and could become a useful tool for prediction of outcome from chemotherapy in mCRC.Despite the availability of several effective cytotoxic drugs and new biological agents the prognosis of metastatic colorectal cancer (mCRC) is still poor and the curative options are limited to a subgroup of patients with resectable metastasis. Consequently, the majority of patients will be offered several lines of palliative chemotherapy, which imply a high level of side effects and careful selection of patients and monitoring during therapy is therefore essential. Irinotecan (a semisynthetic analog of camptothecin) is widely used in combination with flouropyrimidines or as monotherapy for mCRC. 1 The major dose limitating toxicities include diarrhea and myelosupression. 2,3 Better selection criteria in terms of predictive and prognostic markers to optimize treatment are needed.The presence of circulating nucleic acids in peripheral circulation was discovered more than 60 years ago by Mandel and Metais 4 followed by Leon et al. 5 in 1971 who later described the importance of circulating tumor DNA in cancer development. A substantial proportion of the circulating cell-free DNA (cfDNA) in cancer patients is believed to originate from tumor cells. 6,7 Recent studies have consequently focused on the multipurpose utility of cfDNA for molecular characterization to aid in...

Circulating DNA as a Strong Multimarker Prognostic Tool for Metastatic Colorectal Cancer Patient Management Care

“…Several reports have already described the potential impact of ccfDNA on the prognosis of patient outcome in terms of either OS or progression-free survival (6,9,28,29). Most of these previous publications were oriented to analyze the correlation between an increase in the total level of ccfDNA with a decrease in PFS and OS.…”

“…Tumor cells release ccfDNA, which exhibits the genetic and epigenetic alterations of the tumor of origin (4). The clinical significance of tumor-derived ccfDNA released in the blood of patients with colorectal cancer has already been investigated as a prognostic tool in previous studies using various technologic approaches (5)(6)(7)(8)(9). In a recent large meta-analysis, a high correlation between ccfDNA concentration and mCRC patient survival was observed, revealing that patients with relatively low levels of ccfDNA lived significantly longer than patients with higher levels (6).…”

Methodological, biological and clinical aspects of circulating free DNA in metastatic colorectal cancer

“…Identical laboratory methods were used, and the analyses showed similar baseline levels in all cohorts of mCRC patients [32,33,[54][55][56][57][58][59]. Furthermore, analysis of samples from a large normal cohort enabled definition of an upper normal limit [57]. In addition, the levels of cfDNA seem stable between different cohorts of CRC patients, (whereas some differences seem to exist between different tumor types as illustrated in the data from Perkins et al [64]).…”

“…Although the potential that lies in detection and measurement of the tumor-specific DNA has been established, the clinical value of total cfDNA quantification is still being debated. Only few studies take the total levels of cfDNA into consideration as a picture of the overall complex biology, but recently a series of studies reported a clear correlation between total cfDNA levels and mutated DNA [45,[54][55][56][57][58][59][60][61][62][63].…”

“…Still, in a series of seven independent and consecutively conducted Danish phase II trials in mCRC, the levels of cfDNA were measured immediately prior to initiation of therapy. Identical laboratory methods were used, and the analyses showed similar baseline levels in all cohorts of mCRC patients [32,33,[54][55][56][57][58][59]. Furthermore, analysis of samples from a large normal cohort enabled definition of an upper normal limit [57].…”