Circulating tumor DNA dynamics as an early predictor of recurrence in patients with radically resected colorectal cancer: Updated results from GALAXY study in the CIRCULATE-Japan.

• DOI: 10.1200/jco.2023.41.16_suppl.3521
• Publication Date: 2023-06-04T15:36:10Z
• Authors: Eiji Oki; Daisuke Kotani; Yoshiaki Nakamura; Saori Mishima; Hideaki Bando; Hiroki Yukami; Koji Ando; Masaaki Miyo; Jun Watanabe; Keiji Hirata; Naoya Akazawa; Kun-Huei Yeh; George Laliotis; Shruti Sharma; Minetta Liu; Hiroya Taniguchi; Ichiro Takemasa; Takeshi Kato; Masaki Mori; Takayuki Yoshino
• Keywords: Circulating tumor DNA; Clinical endpoint; Primary tumor

3521 Background: Postoperative circulating tumor DNA (ctDNA)-based molecular residual disease (MRD) is reported to be associated with a high risk of recurrence. Here, we present an updated analysis and the lead time interval (LTI) ctDNA positivity radiographic recurrence in patients (pts) radically resected colorectal cancer (CRC), stage II-IV observational GALAXY study. Methods: Serial was analyzed using personalized tumor-informed assay (Signatera bespoke multiplex-PCR NGS assay) at 1 (4-week MRD point), 3, 6, 9, 12, 18, 24 months after surgery until recurrence, CT scans were conducted every 6 months. The primary endpoint disease-free survival (DFS), defined as between date diagnosis relapse or death due any cause. LTI from first positive post-surgery Results: Among 3,615 CRC pts who enrolled May 2020 April 2022 study, 2,083 that met inclusion criteria this report. median follow-up period 16.3 Of analyzed, 286 (14%) ctDNA-positive 4-weeks point 1,797 (86%) ctDNA-negative. Pts ctDNA-positivity timepoint demonstrated inferior DFS 12 times more likely recur, compared ctDNA-negative (HR:12, 95CI: 9.1-15%; p < 0.0001). We further combined status BRAF V600E 4-week observed mutation showed significantly shorter wild-type (p 0.001). Whereas, ctDNA-negativity no significant difference = 0.306). On performing dynamics weeks, remained (N 1529), for converted 112, HR: 14.5, 95%CI: 8.8-23.8%, 0.0001) 124, 25.4, 18.3-35.3; Radiographic 186 (46%). these, 121 (65%) had imaging performed months, per protocol. 142 days (IQR, 43-189 days). Conclusions: Our study builds on existing evidence recently published, prospective prognostic patient outcomes most factor regardless status. predicted radiologic several ahead clinical postoperative should examined carefully ctDNA-guided adjuvant strategy will established by ongoing randomized VEGA ALTAIR studies CIRCULATE-Japan. Clinical trial information: UMIN000039205 .