| Abstract: |
The goal of chemotherapy is to inhibit or slow down rapidly proliferating cells. This avoids tumor multiplication, thus invasion and metastasis. However, since CTDs (chemotherapeutic drugs) cannot distinguish normal and mutated cells, toxic effects are common with both population of cells. Traditional CTDs primarily target macromolecular synthesis and cellular functions of neoplastic cells by interfering with DNA, RNA, proteins synthesis and signal processing. When stalling of these processes are sufficient, it leads to cell death in many forms. Multiple doses of CTDS are often required to kill neoplastic cells. Some of the CTDs are cytotoxic drugs, and they are active during specific stages of cell cycle (G0, G1, S or M), whereas some are non-specific. CTDs are often given in combination to avoid drug resistance. Cellular mechanisms that promote or suppress cell proliferation are complex, involve several genes, receptors, and signal transduction pathways; therefore, adjuvant therapies are becoming popular. Combined modalities like chemotherapy and radiation are also used to shrink the tumor before the surgery. Adjuvant therapy is now the standard for breast, lung, colorectal, and ovarian cancers. Studies have repeatedly shown that multitargeted therapy or combination therapy is far more superior to single-agent therapy. Combination CTDs with fundamentally different mechanisms of actions, and nonoverlapping toxicities have shown to avert resistance. A host of monoclonal antibodies are also used to treat different types of cancers, many that target cellular antigens, some activate the immune response, and a few tag cancer cells to make them vulnerable to attack. Overall, oncotherapeutics has made considerable progress in the last two decades. © 2024 Elsevier Inc. All rights reserved. |
