Circulating cell-free DNA: A promising marker of pathologic tumor response in rectal cancer patients receiving preoperative chemoradiotherapy

Marco Agostini, Salvatore Pucciarelli, Maria Vittoria Enzo, Paola Del Bianco, Marta Briarava, Chiara Bedin, Isacco Maretto, Maria Luisa Friso, Sara Lonardi, Claudia Mescoli, Paola Toppan, Emanuele Urso, Donato Nitti

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Abstract

Purpose: The circulating cell-free DNA (cfDNA) in plasma has been reported to be a marker of cancer detection. The aim of this study was to investigate whether the cfDNA has a role as response biomarker in patients receiving preoperative chemoradiotherapy (CRT) for rectal cancer. Methods: Sixty-seven patients (median age 61 years; male/female 42/25) who underwent CRT for rectal cancer were evaluated. After tumor regression grade (TRG) classification was made, the patients were classified as having disease that responded (TRG 1-2) and that did not respond (TRG 3-5) to therapy. Plasma samples were obtained from patients before and after CRT. The cfDNA levels were analyzed by quantitative real-time polymerase chain reaction of β-globin. On the basis of the Alu repeats, the cfDNA was considered as either total (fragments of 115 bp, Alu 115) or tumoral (fragments of 247 bp, Alu 247). The association between the pre- or post-CRT levels and between variations during CRT of the Alu 247, Alu 115 repeat, and Alu 247/115 ratio (cfDNA integrity index) and the pathologic tumor response was analyzed. Results: The baseline levels of cfDNA were not associated with tumor response. The post-CRT levels of the cfDNA integrity index were significantly lower in responsive compared to nonresponsive disease (P = 0.0009). Both the median value of the Alu 247 repeat and the cfDNA integrity index decreased after CRT in disease that responded to therapy (P <0.005 and P <0.005, respectively) compared to disease that did not respond to therapy (P = 0.83 and P = 0.726, respectively). The results of the multivariable logistic regression analysis showed that only the cfDNA integrity index was significantly and independently associated with tumor response to treatment. Conclusions: The plasma levels of the longer fragments (Alu 247) of cfDNA and the cfDNA integrity index are promising markers to predict tumor response after preoperative CRT for rectal cancer.

Original languageEnglish
Pages (from-to)2461-2468
Number of pages8
JournalAnnals of Surgical Oncology
Volume18
Issue number9
DOIs
Publication statusPublished - Sep 2011

ASJC Scopus subject areas

  • Surgery
  • Oncology

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    Agostini, M., Pucciarelli, S., Enzo, M. V., Del Bianco, P., Briarava, M., Bedin, C., Maretto, I., Friso, M. L., Lonardi, S., Mescoli, C., Toppan, P., Urso, E., & Nitti, D. (2011). Circulating cell-free DNA: A promising marker of pathologic tumor response in rectal cancer patients receiving preoperative chemoradiotherapy. Annals of Surgical Oncology, 18(9), 2461-2468. https://doi.org/10.1245/s10434-011-1638-y