Treatment monitoring in metastatic colorectal cancer patients by quantification and KRAS genotyping of circulating cell-free DNA.
Treatment of metastatic colorectal cancer (CRC) has continuously improved over the last decade. However, disease monitoring remains underdeveloped and mostly dependent on imaging e.g. RECIST 1.1 criteria. The genetic landscape of individual cancers and subsequently occurring treatment-induced evolution remain neglected in current surveillance strategies. Novel biomarkers demand minimally invasive and repetitive tracking of the cancer mutagenome for therapy stratification and to make prognostic predictions. Carcinoembryonic antigen (CEA), a routinely used tumor marker for CRC, does not meet these goals and thus prevents its use as a reliable monitoring tool. A tumor-derived fraction of circulating cell-free DNA (cfDNA), isolated from blood samples, may bypass the limitations of currently available biomarkers and could be a tool for noninvasive disease monitoring. Here, total cfDNA levels differentiated a cohort of metastatic CRC patients from healthy controls. Furthermore, we correlated cfDNA during chemotherapy of 27 stage IV patients with clinical parameters to establish its prognostic and predictive value. Indeed, cfDNA levels in chemotherapy naive patients correlate with the tumor burden and CEA values at diagnosis and increase upon disease progression during 1st and 2nd line treatment. Moreover, we confirm the possibility of cfDNA-based genotyping of KRAS to early detect the emergence of resistance during chemotherapy. These data indicate that repetitive quantitative and mutational analysis of cfDNA might complement current treatment standards but may have also limited value in some patients.
Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, Ulm, Germany.
Andreas W
AW
Berger
Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, Ulm, Germany.
Daniel
D
Schwerdel
Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, Ulm, Germany.
Hanna
H
Welz
Institute of Pathology, Ulm University, Albert-Einstein-Allee 23, Ulm, Germany.
Ralf
R
Marienfeld
Department of Diagnostic and Interventional Radiology, Ulm University, Albert-Einstein-Allee 23, Ulm, Germany.
Stefan A
SA
Schmidt
Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, Ulm, Germany.
Alexander
A
Kleger
Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, Ulm, Germany.
Thomas J
TJ
Ettrich
Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, Ulm, Germany.
Thomas
T
Seufferlein
D000328:Adult; D000970:Antineoplastic Agents / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000235:genetics; D002272:Carcinoembryonic Antigen / Q000235:genetics; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000235:genetics*; D004252:DNA Mutational Analysis / Q000379:methods; D004273:DNA, Neoplasm / Q000235:genetics*; D018450:Disease Progression; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D009154:Mutation / Q000235:genetics; D011379:Prognosis; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics*
D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D004273:DNA, Neoplasm; C117307:KRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras)