A COMPHRENSIVE REVIEW: DRUG RESISTANCE IN CANCER CHEMOTHERAPY: MECHANISMS AND STRATEGIES TO OVERCOME

Chemotherapy failure due to cancer resistance prevents patients from achieving long-lasting therapeutic benefits.[1,2] Some tumours are resistant from the start (intrinsic resistance), while others become resistant over time as treatment continues (acquired resistance).[1,3] The body develops resistance through biological mechanisms, including drug elimination processes, detoxification system enhancements, target protein changes, DNA repair system improvements, cell death resistance, tumour cell adaptability, and environmental assistance from tumour surroundings.[1,4] Research discoveries have identified cancer stem cells, metabolic changes, epigenetic controls, and non-coding RNA networks as factors that create drug resistance.[2,5] Researchers have found various resistance pathways in cancer cells so we need multiple treatment approaches which should combine different therapy methods to fight this issue.[1,4,6] Scientists use six different methods to fight resistance because they mix drugs smartly with resistance pathway blocking, epigenetic treatments, nanoparticle drug delivery, immunotherapy, and molecular testing-based patient care.[6,9] The review examines why drugs lose their effectiveness against cancer cells while it also discusses proven and emerging techniques which can restore cancer cell sensitivity to treatments.[1,4,9]