Neoadjuvant chemotherapy (neoCTx) followed by hepatic resection is the treatment of choice for patients with colorectal cancer liver metastasis (CLM). Treatment response is generally assessed using radiologic imaging after several cycles of chemotherapy. However, earlier assessment of response would be desirable since nonresponders could be switched early to an alternative chemotherapy regimen. Recent evidence suggests that circulating free methylated tumor DNA is a highly sensitive biomarker and may more accurately reflect tumor burden and treatment response than conventional markers for CRC.
Thirty-four patients with CLM who received neoCTx prior to intended hepatic resection were included in this prospective nonrandomized study. Peripheral blood plasma was collected at baseline and before each cycle of neoCTx and was then analyzed for aberrant methylation of 48 CRC-associated genes. Methylation marker levels were correlated with baseline tumor volume and treatment response and compared with the standard tumor markers CEA and CA 19-9.
The methylation markers SEPT9, DCC, BOLL, and SFRP2 were present in all patients at baseline and displayed a stronger correlation with tumor volume than CEA and CA 19-9. Serial measurement of these methylation markers allowed for discrimination between operated and nonoperated patients already after 1 cycle of neoCTx with high sensitivity and specificity. The early dynamic changes of SEPT9 and DCC also seemed to correlate with pathohistological response.
Our data suggest that serial measurements of CRC-associated methylation markers could be a particularly valuable tool for early response assessment in patients receiving neoCTx for CLM.
*Department of Surgery, Medical University of Vienna, Vienna, Austria
†Department of Pathology, Medical University of Vienna, Vienna, Austria
‡Center for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Vienna, Austria
§Department of Radiology, Medical University of Vienna, Vienna, Austria
¶Austrian Institute of Technology, Vienna, Austria
||Department of Surgery, Rudolfstiftung Hospital, Vienna, Austria
**Surgical Research Laboratories, Medical University of Vienna, Vienna, Austria
††Clinical Department of Medical and Chemical Laboratory Diagnostics, Medical University of Vienna, Vienna, Austria.
Reprints: Thomas Bachleitner-Hofmann, MD, Department of Surgery, Medical University of Vienna, Austria, Währinger Gürtel 18-20, A-1090 Vienna, Austria. E-mail: email@example.com.
The study was supported by the research grant No. 14786 by the Jubilee Fund of the National Bank of Austria.
The authors report no conflicts of interest.