What is chemotherapy?
Chemotherapy is the use of biochemical methodologies to destroy cancer cells. The chemotherapeutic drugs usually work by preventing the cancer cells from growing, proliferating and invading other tissues. Since cancer cells have the ability to grow and proliferate faster than normal cells, chemotherapeutic agents have had a decent effect on restricting the raging dominance of cancer cells.
Evolution of Cancer Chemotherapy
Here are some of the historical landmarks in the evolution of cancer chemotherapy:
- In the early 19th century radical, super-radical and ultra-radical surgery, was propagated by William S Halstedt.
- Radical mastectomy was used to treat breast cancer for nearly about 90 years, between 1891 and 1981.
- In 1981, Bernhard Fisher disproved radical surgery as the treatment for cancer. This reduced the use of radical surgery dramatically and it was also catalyzed by the advent of systemic adjuvant therapy (which includes radiation and the application of cytostatic drugs), in combination with local surgery, producing similarly efficient results.
- In the late 1970s, bleomycin, vinblastine and cisplatin were novel drugs used to prevent cancer dissemination and metastasis. However, they had severe side effects, including vomiting nearly 12 times per day. This situation was aggravated by the fact that antiemetic drugs were not available at this time. This left the patients with no other option but to tolerate these harsh side effects.
- By 1979, the US National Cancer Institute (NCI), which was involved in research into cytostatic drugs, had constructed a network of 20 cancer centres. These centres were involved in conducting new studies of cancer therapy, designing control measures and sending reports to the clinical boards which were involved in the approval and coordination of studies involving human subjects. Some of the cytostatic drugs which were approved in this process had low effectiveness and severe side effects.
- With a more and better scientific understanding of the basis of cancer metastasis in animal tumour models (a method not widely practised before) and significant progress made in molecular biology, immunology and virology, over the last 60 years, novel types of cancer treatment could be developed. Targeted therapies via small molecule inhibitors (SMIs) or monoclonal antibodies (MAbs) came into the field of cancer chemotherapy.
- In recent years, two novel types of immunotherapy have made a mark in clinical oncology:
- Checkpoint inhibitory MAbs
- Chimeric antigen-specific receptor (CAR)-transfected T-cells (CAR-T cells)
- The rise of cancer immunotherapy has occurred over the past decade due to its effectiveness against cancer. Antigen-specific immune responses have been found to be very effective, even in the later stages of cancer.
- Antitumor vaccines and oncolytic viruses (OVs) have also been developed in recent decades. They are reportedly physiological and well-tolerated.
More research in understanding the hallmarks of cancer are leading to identification of potential cancer targets against which effective therapeutic solutions can be specifically targeted and easily administered.
Here is a list of the common side effects of traditional cancer chemotherapy:
- Muscle pain
- Stomach pain
- Pain from nerve damage, that might cause burning, numbness, or shooting pains, usually in the fingers and toes
- Mouth and throat sores
- Nausea and vomiting
- Blood disorders
- Nervous system effects:
- Weakness or numbness in the hands, feet, or both
- Weak, sore, tired, or achy muscles
- Loss of balance
- Shaking or trembling
- Stiff neck or headache
- Problems seeing, hearing, or walking normally
- Feel clumsy
- Cognitive dysfunction
- Sexual and reproductive issues
- Appetite loss
- Hair loss
- Heart health
- Long-term side effects
- Post-treatment changes in the nervous system
- Naturally Occurring Gut Bacteria Can Clean Up Chemotherapy Toxins in the Body
- Peto’s Paradox – An Answer to Cancer Therapy?
- Schirrmacher V. (2019). From chemotherapy to biological therapy: A review of novel concepts to reduce the side effects of systemic cancer treatment (Review). International journal of oncology, 54(2), 407–419. https://doi.org/10.3892/ijo.2018.4661