Chemotherapy

Chemotherapy

Chemotherapy entails using antineoplastic drugs or a combination of such drugs in a standardized treatment regimen to combat cancer.

The primary mechanism of action for most chemotherapy agents is targeting rapidly dividing cells, a characteristic shared by many cancer cells. However, this also affects normal cells with high rates of division, including those in the bone marrow, digestive tract, and hair follicles. Consequently, common side effects include myelosuppression (reduced blood cell production leading to immunosuppression), mucositis (inflammation of the digestive tract lining), and alopecia (hair loss).

Newer anticancer drugs focus on abnormal proteins in cancer cells, a strategy termed targeted therapy, which technically differs from traditional chemotherapy.

The origins of chemotherapy trace back to the early 20th century, initially unrelated to cancer treatment. Mustard gas, used as a chemical weapon in World War I, was observed to suppress blood production. Similar compounds, known as nitrogen mustards, were studied further during World War II, leading to their testing in patients with advanced lymphomas. This historical convergence paved the way for chemotherapy's development, with mustine being the first drug derived from this research.

While modern chemotherapy predominantly refers to cancer treatment, historically, the term encompassed the use of chemicals to treat various ailments, including microbial infections (antibacterial chemotherapy). Early chemotherapeutic agents like arsphenamine, sulfonamides, and penicillin were instrumental in treating conditions like syphilis.

Cancer arises from uncontrolled cell growth, often influenced by genetic predisposition and environmental factors, leading to invasive and metastatic behavior.

Chemotherapeutic drugs typically disrupt cell division, primarily targeting fast-dividing cells and inducing apoptosis (programmed cell death). However, their impact extends to normal rapidly dividing cells, resulting in side effects.

Tumors with high growth fractions, such as acute myelogenous leukemia, respond better to chemotherapy due to a larger proportion of dividing cells. Conversely, slow-growing tumors, like indolent lymphomas, exhibit limited responses.

Solid tumors pose challenges due to reduced drug penetration and decreased cell division at the tumor's core. Radiation therapy and surgery complement chemotherapy in addressing these issues.

Over time, cancer cells may develop resistance to chemotherapy, attributed in part to efflux pumps that expel drugs from cells. Research continues to explore inhibitors of these pumps to enhance chemotherapy effectiveness.