History of Cancer Treatments: Chemotherapy
Chemotherapy in the 1930s – Naval personnel expose to mustard gas through military action found to have toxic changes in bone marrow cells that progress into blood cells. During that same period, the US Army studied several chemicals related to mustard gas to grow more effective agents for warfare and develop protective measures. In that work, a compound called nitrogen mustard was investigated and found to work against a cancer of the lymph nodes called lymphoma. This agent helped as a model for a long series of similar but more effective agents that killed fast-growing cancer cells by damaging their DNA.
Not long after discovering nitrogen mustard, a compound linked to the vitamin folic acid produced reductions in children with severe leukemia. Aminopterin jammed a critical chemical reaction necessary for DNA replication. That drug was the predecessor to methotrexate, a commonly used cancer treatment drug. Since then, other researchers have discovered drugs that block further cell growth and replication functions. The era of chemotherapy had started.
Over the years, chemotherapy (chemo) drugs have successfully treated many people with cancer. First cured in 1956 once methotrexate was used to treat a rare tumor called choriocarcinoma. Treatments of testicular cancer were seen over the next decade. Many other types of cancer can be controlled with chemotherapy for long periods, even if they are not cured.
Several approaches are available to improve activity and reduce the side effects of chemotherapy. These include:
- New drugs, new drug combinations, and new administration methods
- Novel approaches that aim drugs more specifically at cancer cells to produce fewer side effects
- Medications to reduce side effects, such as colony-stimulating factors, chemoprotective agents (such as dexrazoxane and manifesting), and antiemetics (to reduce nausea and vomiting)
- Agents that overcome multidrug resistance (when cancer does not respond to the usual treatment drugs)
In the early 20th century, only cancers small and localize enough to be removed entirely by surgery were treatable. Later, radiation was used after surgical treatment to control minor tumor growths that were not surgically detached. Finally, it destroys small tumor advances that had spread beyond the reach of the surgeon and radiation therapist. Chemotherapy used after surgery to kill any remaining cancer cells in the body is calles adjuvant therapy. Adjuvant therapy was first tested in breast cancer and found to be effective. Later it used in colon cancer, testicular cancer, and others.
How are Chemotherapy Treatment Cycles Determines in Cancer Patients?
In the first investigations carried out with drugs, first in preclinical studies and later in phase I clinical trials, pharmacokinetics, and pharmacodynamic studies show how these drugs interact with our body and vice versa.
Pharmacodynamics studies the action of drugs and their effects on the body. It is how you find the ideal dose and frequency—balancing what is effective and what the body can tolerate. Always based on studies, always on clinical trials.
Both the dose and the frequency have modify for better tolerance, but I repeat, under clinical trial.
How do Chemotherapy Cycles Work?
I will give you an example. We use intravenous adjuvant chemotherapy in breast cancer called paclitaxel every three weeks. It was possible to destroy the cancer cells that circulated in the blood in this way. Still, the tolerance was not very good. The patients suffered from fatigue. Their bone marrow did not have time to fully recover, causing a decrease in defenses, platelets, and globules—Red (anemia).
Sometime later, another clinical trial was carried out with this drug, dividing the total dose every 21 days into three parts, administering each third once a week. Instead of giving a large quantity every 21 days, a small amount is given every week. So patients had fewer side effects, but the drug was still effective.
Cancer treatment is complex. We need to check the cells that want to grow without stopping but without causing severe side effects. For this, clinical trials are essential, in which we study doses, times, routes of administration, drug combinations, etc. Thanks to the patients who participate in them, science can continue to advance. Thank you.
Types of Chemotherapy
Agents used in chemotherapy are classified into various pharmacological groups according to their structure, mechanism of action, and metabolism. The Goodman and Gilman classification is widely recogniz and has served as a reference for generations of physicians and oncologists. This classification groups the different agents into five large categories:
- Alkylating Agents.
- Natural products
- Hormones and Agonists.
- Miscellaneous Agents.
The different groups, the most representative agents, mechanism of action, metabolism, and main toxicities are summarize. This table does not include tyrosine kinase inhibitors (target therapies) or immunotherapy, as these agents are generally not considering cytotoxic agents.
To block, inhibit, or modify critical cell structures that are ideally unique to cells with malignant biological behavior by the chromosomal translocation known as the Philadelphia chromosome responsible for oncological transformation in chronic myeloid leukemia. Although reality, all agents, in one way or another, have been ” target therapies” due to the ability to inhibit or affect critical structure for the functioning of malignant cells, the term coin in 2001 with approval. This new group of agents, also known as tyrosine kinase inhibitors or target therapies, was develop.
Experts Assure that Chemotherapy Remains the option even in the Most Advanced Cancers.
- They have wanted to deny some hoaxes and fake news, claiming that chemotherapy shortens life when it does not cure. The efficacy of chemotherapy in advanced cancer depends on multiple factors, but it generally exceeds 20 percent, although there are highly chemosensitive tumors, with effectiveness more significant than 80 percent”.
- In this sense, his main statement is that chemotherapy continues to be the primary weapon even against advanced cancer. He says that new alternatives are effective for approximately a third of patients with advanced cancer, such as immunotherapy and other treatments.
- However, the reality is that for now, “many patients treated with chemotherapy are in advanced and incurable phase. The objective is, in most cases, to achieve control of the disease that allows improving the quality of life and, in some cases, making the disease chronic, with the impact that this has on survival”.
Myths about Side Effects
Thus, the expert explains that “if chemotherapy produces severe and fatal complications due to toxicity. It should always consider unexpected toxicity. Something different is that its administration can, especially in young patients. It causes some late effects that impact their quality of life when surviving cancer, but in no case does it impact the duration of life of patients”.
Another idea that this doctor denies is the effects of chemotherapy are incurable: “They depend above all on the type of drug and the dose in which it is administer. They are generally infrequent, and the oncology team puts preventive measures so that they do not occur, and if they do appear, they must be mild. In practically all cases, the side effects of chemo are reversible”, concludes the expert.
Chemotherapy – treats several kinds of cancer. The treatment types will depend on the type of cancer you have, whether and where it has spread, and whether you have other health problems. For some people, chemotherapy may be the only treatment they receive. But more often, you will receive chemotherapy and other cancer treatments.