Early Assessment of Lymphoma Treatment Response Using Phased Variant Analysis With Next-Generation Sequencing

Lymphoma is a prevalent lymphoid malignancy globally and in Taiwan. Large B-cell lymphoma (LBCL) is the most common subtype of aggressive B-cell lymphoma. LBCL's aggressive nature manifests through extranodal involvement, severe symptoms, and relative refractoriness to therapies, leading to a 5-year overall survival rate of 60-70% across developed countries and poorer outcomes in high-risk patients with primary refractory disease. Chemoimmunotherapy remains the primary treatment for LBCL, requiring comprehensive assessment through clinical and imaging examinations, biomarkers, and molecular testing. Currently, computed tomography (CT) and positron emission tomography (PET) scans are the standard modalities for treatment response evaluation, though their radioactive nature calls for the development of safer alternatives. Circulating tumor DNA (ctDNA) analysis has emerged as a promising field, providing insights into tumor molecular characteristics, clinical status, and treatment response by analyzing DNA fragments released from tumor cells into the bloodstream. Dynamic monitoring of ctDNA during treatment can effectively gauge therapeutic efficacy-decreasing ctDNA concentrations suggest successful treatment, while increasing levels may indicate treatment failure or tumor recurrence. The detection of ctDNA has been much improved through advances in next-generation sequencing (NGS) technologies, particularly taking advantage of analyzing phased variants, consecutive gene mutations on the same chromosome, enhances the sensitivity and specificity.