Precision Chemotherapy: Towards Personalized Cancer Treatment

Precision chemotherapy represents a paradigm shift in oncology, tailoring cytotoxic regimens to molecular tumor profiles to improve efficacy and reduce toxicity. A multicenter observational study was conducted in Mexico and Ecuador with patients diagnosed with breast, colorectal, ovarian, and cervical cancers. Clinical and demographic data were collected, and molecular profiling was performed using tissue-based next-generation sequencing (NGS) and plasma-derived circulating tumor DNA (ctDNA). Outcomes included objective response rate (ORR), progression-free survival (PFS), overall survival (OS), toxicity, and patient-reported quality of life (QoL). High concordance above 80% was observed between NGS and ctDNA for key biomarkers, with BRCA1/2 and MMR/MSI alterations associated with superior ORR, PFS, and OS, whereas KRAS mutations correlated with poorer outcomes. Biomarker-guided chemotherapy significantly reduced grade ≥3 adverse events compared with conventional regimens and improved QoL scores by 8–10 points across functional domains (EORTC QLQ-C30). These findings confirm that precision chemotherapy enhances efficacy, tolerability, and patient-centered outcomes, while the binational experience in Mexico and Ecuador highlights both feasibility and the urgent need for equitable access to molecular diagnostics in Latin America. Precision chemotherapy should be prioritized as a central component of global cancer control strategies.