Circulating Tumor DNA for Customisation of Tumor Immunotherapy: Technology Advance and Clinical Evidence

Abstract

Circulating tumour DNA (ctDNA) in blood is now used in a less invasive way to guide personalised cancer therapy. Several blood tests can be conducted on ctDNA to determine whether there is a distant spread of cancer cells, discover microscopic cancer cells remaining after surgery, and observe how the immune system responds to immunotherapy in time; thus, repeated tissue biopsies and delayed CT scans are reduced. The previous way of diagnosis cannot rapidly identify gene mutations in lesions, and frequent ctDNA tests can promptly detect cross-regional and time-dependent genomic alterations to provide real-time molecular support for clinical decisions. This paper first sorts out updated performance and lingering defects of current ctDNA detection platforms, then analyzes real clinical data covering four major tumor types: breast malignancies, colorectal carcinoma, melanoma, non-small cell lung cancer (NSCLC). Multiple prospective cohort observations and pooled meta-analysis data show that ctDNA surveillance can divide patients into high- and low-risk groups for recurrence, detect molecular relapse months before any visible lesion enlargement on scans, and identify newly arising drug-resistant mutant clones ahead of imaging signals. All collected clinical evidence shows that ctDNA serves as a daily diagnostic aid to continuously optimise the entire implementation logic of personalised tumour immunotherapy.