Cell-free DNA and preoperative chemoradiotherapy for rectal cancer: a systematic review.

Background: Preoperative chemoradiotherapy is the standard of care for patients with locally advanced rectal cancer, yet valid circulating biomarkers are lacking. We aimed at systematically reviewing the literature of cell-free DNA and locally advanced rectal cancer.

Methods: A systematic literature search was performed. We retrieved papers reporting a correlation between a clinical outcome and cell-free DNA for patients receiving chemoradiotherapy for locally advanced rectal cancer.

Results: We included nine studies of a total of 615 patients. Only single-arm studies were identified, analyzing either the total level of cell-free DNA or tumor-specific DNA. Despite differences in the methodology and outcomes, eight of the nine studies showed a correlation between cell-free DNA and a clinical outcome.

Conclusions: Cell-free DNA might hold prognostic and predictive information for patients with locally advanced rectal cancer receiving preoperative chemoradiotherapy; although, firm conclusions are limited by the heterogeneity in this field.