Circulating cell-free DNA in plasma of locally advanced rectal
cancer patients undergoing preoperative chemoradiation: A potential diagnostic
tool for therapy monitoring
Affiliations: Department of General and Transplant Surgery,
Innsbruck Medical University, Austria | Molecular Oncology Group, Department of Obstetrics and
Gynecology, Vienna Medical University, Austria | Department of Radiotherapy and Radiooncology,
Innsbruck Medical University, Austria | Tyrolean Cancer Research Institute, Innsbruck,
Austria | Department of Medical Statistics, Informatics and
Health Economics, Innsbruck Medical University, Austria | Department of Radiooncology, Feldkirch General
Hospital, Academic Teaching Hospital, Feldkirch, Austria
Note: [] Corresponding author: Dietmar Öfner, MD, Department of
General and Transplant Surgery, Innsbruck Medical University, Anichstrasse 35,
A-6020 Innsbruck, Austria. Tel.: +43 512 5040; Fax.: +43 512 504 28519; E-mail:
dietmar.oefner@i-med.ac.at
Abstract: Circulating cell-free DNA opens up an interesting field for therapy
monitoring, in particular during multimodal therapy protocols. The objective of
this proof of principle study was to evaluate whether the amount of circulating
plasma DNA has the potential to serve as a marker for therapy monitoring during
the treatment course of locally advanced rectal cancer patients. We especially
focused on kinetics of circulating DNA to assess whether variances in kinetics
have the potential to discriminate between therapy responders and
nonresponders. The amount of circulating DNA in plasma of rectal cancer patients
undergoing preoperative chemoradiation was determined using real-time PCR
before chemoradiation, after the end of chemoradiation and at the end of
treatment. The study population was divided into responders (ypT0-T2 stage) and
nonresponders (ypT3-T4 stage). Both groups showed comparable median plasma DNA
values before and after the end of chemoradiation. At the end of treatment
responders showed a further decrease in circulating DNA, whereas in
nonresponders the circulating DNA manifestly increased (P =
0.006). This study demonstrates that circulating DNA in plasma of rectal
cancer patients undergoing preoperative chemoradiation might serve as a
surrogate marker to discriminate between responders and nonresponders.
Therefore, we hypothesize that quantification of plasma DNA could be of use as
an easily accessible tool for therapy monitoring in these patients.
