Rechallenge Therapy: New Dimensions in Cancer Therapy

Introduction: The evolution of resistance to different types of cancer therapies has become a significant challenge in oncology research, leading to disease progression and limited treatment options. Rechallenge therapy, where a previously used treatment is reintroduced after a period of discontinuation, has emerged as a potential strategy to overcome resistance. Methods: This review synthesizes current knowledge on rechallenge therapy by analyzing data from clinical trials, retrospective studies, and case reports. A comprehensive examination was conducted across multiple cancer types and therapeutic classes, including immunotherapy, chemotherapy, targeted therapy, hormonal therapy, and combination approaches. Results: The efficacy of rechallenge therapy varies across cancer types. For instance, in metastatic colorectal cancer, anti-EGFR rechallenge therapy has shown response rates of 20–30% in RAS wild-type patients after a drug-free interval. In prostate cancer, rechallenge with androgen deprivation therapy or abiraterone has demonstrated biochemical response rates of approximately 30–40% in selected populations. Discussion: In hormone receptor–positive breast cancer, endocrine therapy rechallenges, especially following a treatment break, have yielded clinical benefit rates of over 40% in some cohorts. These outcomes are influenced by tumor biology, duration of prior response, molecular profiling, and patient selection criteria. Conclusion: Rechallenge approaches show promise as viable options for treating cancer recurrence and resistance, but their application must be carefully tailored to each patient. A well-planned scientific strategy is required to optimize different rechallenge approaches, identify predictive biomarkers, and understand the longterm outcomes associated with this method.