PO.CL01.09 · 临床研究
通过循环肿瘤DNA分析检测结直肠癌患者术后的微小残留病灶
Detection of minimal residual disease in colorectal cancer patients after surgery through circulating tumor DNA profiling
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
在以根治为目的的切除术后准确识别微小残留病灶（MRD），仍是结直肠癌（CRC）中一项关键的未满足需求。鉴于当前辅助化疗（ACT）改善预后的术后窗口期狭窄，快速且可靠的生物标志物对指导及时的治疗决策至关重要。在此，我们评估了一个靶向液体活检突变面板用于术后ctDNA检测的预后性能，以识别MRD并支持CRC中的ACT决策。我们使用Thermo Fisher Scientific NGS平台（基于Ion S5 Oncomine的面板）进行靶向测序，评估关键CRC相关基因中的200余个热点突变。所有样本使用10–20 ng的cfDNA测序至约50,000×的平均深度，从而能够检测VAF>0.05%的变异。在49例可切除的I–III期CRC患者（32例结肠癌，17例直肠癌）中，于治疗前后评估ctDNA，血液样本于基线以及术后或新辅助治疗后4周采集。基线ctDNA改变在75%的患者中被检出（37/49），III期检出率（78%；21/27）高于II期（69%；11/16）和I期（67%；4/6）。在所有基线阳性样本中，共在10个基因中鉴定出76个突变，主要为TP53（n=26）、APC（n=14）、KRAS（n=10）和PIK3CA（n=6），中位VAF为0.97%（范围0.05–17.9%）。治疗后ctDNA阳性见于57%的患者（28/49），提示持续存在MRD。治疗后VAF下降见于30%（15/49），其中9例患者降幅>50%，与部分分子反应但仍有亚临床疾病相一致。相反，27%（13/49）显示VAF升高，提示治疗反应不足及复发风险较高。ctDNA完全清除见于24%的患者（12/49），其中8例结肠癌和4例直肠癌，所有这些患者至少12个月保持无事件。截至目前，一例直肠癌患者保持ctDNA阴性达18个月。最后，18%的患者在两个时间点均无可检测到的突变，凸显了进一步完善检测方法以提高该亚组检测灵敏度的必要性。总之，术后ctDNA阳性识别出具有持续分子疾病的患者，而ctDNA清除与短期无事件结局相关。这些发现支持将ctDNA分析用作指导术后治疗决策的实用工具。
查看英文原文 English abstract
Accurate identification of minimal residual disease (MRD) after curative-intent resection remains a critical unmet need in colorectal cancer (CRC). Given the narrow postoperative window during which current adjuvant chemotherapy (ACT) improves outcomes, rapid and reliable biomarkers are essential to guide timely treatment decisions. Here, we assess the prognostic performance of a targeted liquid-biopsy mutation panel for postoperative ctDNA detection to identify MRD and support ACT decision-making in CRC. We performed targeted sequencing using a Thermo Fisher Scientific NGS platform (Ion S5 Oncomine based panel) to assess more than 200 hotspot mutations across key CRC-associated genes. All samples were sequenced to a mean depth of ~50,000× using 10-20 ng of cfDNA, enabling detection of variants with a VAF >0.05%. ctDNA was evaluated before and after treatment in 49 patients with resectable stage I-III CRC (32 colon, 17 rectal), with blood samples collected at baseline and again 4 weeks after surgery or neoadjuvant therapy. Baseline ctDNA alterations were detected in 75% of patients (37/49), with higher detection rates in stage III (78%; 21/27) compared with stage II (69%; 11/16) and stage I (67%; 4/6). Across all baseline-positive samples, 76 mutations were identified in 10 genes, predominantly TP53 (n=26), APC (n=14), KRAS (n=10), and PIK3CA (n=6), with a median VAF of 0.97% (range 0.05-17.9%). Post-treatment ctDNA positivity was observed in 57% of patients (28/49), indicating persistent MRD. A reduction in VAF after treatment occurred in 30% (15/49), including 9 patients with >50% decreases, consistent with a partial molecular response but ongoing subclinical disease. Conversely, 27% (13/49) showed increased VAF, suggesting inadequate treatment response and a higher risk of relapse. Complete ctDNA clearance occurred in 24% of patients (12/49), 8 with colon cancer and 4 with rectal cancer, all of whom remain event-free for at least 12 months. Up to date, one rectal cancer patient remains ctDNA-negative for 18 months. Finally, 18% of patients had no detectable mutations at either time point, underscoring the need for further assay refinement to improve detection sensitivity in this subgroup. In conclusion, postoperative ctDNA positivity identified patients with persistent molecular disease, while ctDNA clearance correlated with short-term event-free outcomes. These findings support the use of ctDNA profiling as a practical tool to guide postoperative treatment decisions.
利益披露 Disclosure
L. Maya Janssen, None..
E. Apagnha, None..
F. Teles Barreto, None..
A. de Medeiros Silva, None..
M. Ayrimoraes Soares, None..
J. de Sousa, None..
F. Pittella-Silva, None.