Szeto Säde, Kytölä Soili, Erkan Erdogan Pekcan, Ahtiainen Maarit, Mecklin Jukka-Pekka, Kuopio Teijo, Sallinen Ville, Lepistö Anna, Koskenvuo Laura, Renkonen-Sinisalo Laura, Anttonen Anu, Heiskala Kukka, Tulokas Sanni, Mäkelä Siru, Wirta Erkki-Ville, Tuunanen Tuija, Salminen Tapio, Ristimäki Ari, Seppälä Toni T
Applied Tumor Genomics Research Program, Research Program Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
Department of Genetics, HUS Diagnostic Center, Helsinki University Hospital, Helsinki, Finland.
Cancer Med. 2025 May;14(9):e70943. doi: 10.1002/cam4.70943.
Circulating tumor DNA (ctDNA) can potentially identify rectal cancer patients benefiting from neoadjuvant and adjuvant therapy. This study compared droplet digital PCR (ddPCR) and next-generation sequencing (NGS) for ctDNA detection in localized rectal cancer before and after surgery.
Pre-therapy plasma and rectal tumor samples were collected from a development group (n = 41) and a validation group (n = 26). Mutations in tumor samples were identified using NGS, and ctDNA detection was performed with both ddPCR and NGS. Recurrence was assessed 1 year after surgery in the development group.
In the development group, ddPCR detected ctDNA in 24/41 (58.5%) and NGS panel in 15/41 (36.6%; p = 0.00075) of the baseline plasma. In the validation group, 21/26 (80.8%) patients had detectable ctDNA in the pre-therapy plasma. A positive ctDNA result was associated with higher clinical tumor stage and with lymph node positivity as detected by MRI. Postoperative ddPCR did not detect ctDNA before most recurrences.
We demonstrated a practical oligomarker ctDNA test for localized rectal cancer suitable for clinical workflow, and that ddPCR detects ctNA from pre-therapy plasma at a satisfactory level in advanced rectal cancers. Detecting ctDNA with ddPCR may help to assess the local severity, but the clinical utility of this approach should be evaluated in clinical trials.
循环肿瘤DNA（ctDNA）有可能识别出从新辅助和辅助治疗中获益的直肠癌患者。本研究比较了液滴数字PCR（ddPCR）和下一代测序（NGS）在局部直肠癌手术前后ctDNA检测中的应用。
从一个开发组（n = 41）和一个验证组（n = 26）收集治疗前血浆和直肠肿瘤样本。使用NGS鉴定肿瘤样本中的突变，并同时用ddPCR和NGS进行ctDNA检测。在开发组中，术后1年评估复发情况。
在开发组中，ddPCR在24/41（58.5%）的基线血浆中检测到ctDNA，NGS panel在15/41（36.6%；p = 0.00075）的基线血浆中检测到ctDNA。在验证组中，21/26（80.8%）的患者在治疗前血浆中可检测到ctDNA。ctDNA检测结果为阳性与较高的临床肿瘤分期以及MRI检测到的淋巴结阳性相关。术后ddPCR在大多数复发前未检测到ctDNA。
我们展示了一种适用于临床工作流程的针对局部直肠癌的实用寡标志物ctDNA检测方法，并且ddPCR在晚期直肠癌中从治疗前血浆中检测ctNA的水平令人满意。用ddPCR检测ctDNA可能有助于评估局部严重程度，但这种方法的临床实用性应在临床试验中进行评估。
