2. Antitumor Drugs
2.1 Alkylating Agents
These drugs were developed from wartime research on mustard gases. They interfere with cellular DNA preventing mitosis. Most of these drugs are absorbed after oral administration, but a few are given intravenously. They distribute to all tissues and are toxic to the bone marrow and are in themselves carcinogenic and mutagenic. Some of the agents have additional adverse effects.
Mustard gas is a highly toxic and deadly gas that causes conjunctivitis, blindness and death. Its vapor is extremely poisonous and can be absorbed through the skin. It causes cancer of the bronchi in workers exposed to it and cancer of the lung, larynx, trachea, and bronchi in cancer patients treated with it.
Antimetabolites inhibit a metabolic pathway essential for the viability or reproduction of a cancer cell. No metabolic pathway is unique for cancer cells so all body cells are affected.
Methrotrexate – This drug is toxic to the bone marrow. In addition, it is toxic to the orogastrointestinal epithelium, and two to seven days after administration one often sees oral reddening and ulceration, nausea, and vomiting. Diarrhea, dysphagia, and gastrointestinal bleeding may result as more serious effects. Skin rashes and baldness occasionally are seen. With very large doses, hepatic damage or renal damage progressing to uremia may occur. Prolonged usage is associated with liver damage with a cirrhosis-like syndrome. Leukoencephalopathy (abnormal amount of white blood cells in the brain) may occur.
6-Mercaptopurine (6MP) and 6-thioguanine (6TG) -Toxicity consists of bone marrow depression and orogastrointestinal damage similar to that seen with methotrexate.
Cytarabine (ARA-C, arabinosylcytosine) – A marked bone marrow depressant; causes lesions of orogastrointestinal epithelia, and occasionally gives rise to hepatic and renal toxicity.
5-Fluorouracel (5FU) – This drug can cause devastating bone marrow and gastrointestinal toxicity. Baldness, skin rashes, or cerebellar dysfunction are also noted.
Dacarbazine (DTICJ) – Toxicity includes bone marrow depression, gastrointestinal erosions, marked vomiting, and occasionally an influenza-like syndrome.
A number of antibiotics have antitumor effects. Some are complex alkylating agents; the remainder are
rather large molecules that bind to DNA.
Dactinomycin (actinomycin D) – Toxicity includes bone marrow depression, orogastrointestinal ulceration, nausea and vomiting, and baldness. A specific effect is a severe skin reaction wherever there has been previous (or concomitant) radiation.
Doxorubicin (adriamycin) and Daunorubicin (daunocycin, rubidomycin) – Toxicity includes bone marrow depression, baldness, and orogastrointestinal reactions. They also can result in cardiac failure, often severe and irreversible. Apparently the drugs accumulate in cardiac muscle and result in severe cardiac damage if a certain total dosage is exceeded.
Bleomycin – Bleomycin results in erhythema, pain, and hypertrophic changes in the skin in areas where there is a lot of keratin, and ulceration in these areas and pigmentation of the nails may occur. Pulmonary fibrosis, which is sometimes fatal, occurs in 5 to 15% of patients who receive more than 100 mg/m2. Patients are often given as much as 300 mg/m2.
Mithramycin – Bone marrow toxicity is marked. Mithramycin also results in bleeding by depressing the coagulation factors manufactured by the liver, and it inhibits the activity of osteocytes, depressing serum levels of calcium.
Vincristine and vinblastine – Both drugs result in baldness and bone marrow depression. Both drugs have neuromuscular toxicity (which is more marked for vincristine) leading to severe constipation, paresthesia, loss of reflexes and weakness of extremities.
2.5 Miscellaneous Compounds
Procarbazine – In addition to nausea, vomiting, and bone marrow depression, there are neurologic effects—somnolence, confusion, and cerebellar ataxia.
Hydroxyures – Its main toxicity is bone marrow depression.
Asparaginase – Asparaginase results in many serious toxicities in man, especially in those organs that synthesize large amounts of proteins, such as the liver and pancreas. Liver toxicity is moderate, but an occasional patient will develop pancreatitis. There are occasional central nervous system manifestations and, because it is a protein given IV, some people (about 5% develop “allergic reactions” (severe sensitivities) and sometimes anaphylatic shock.
Mitotane (ortho, para-DDD) – This drug is related to DDT and is especially toxic to the cells of the adrenal cortex. Lethargy and somnolence occur in some people; less common effects include skin rashes, bone marrow depression, and liver damage.
Cisplatin – In addition to severe nausea and vomiting and hematologic depression, its effects include renal damage and ototoxicity.
As you can see, rather than “curing” anything, these drugs make it virtually impossible for the body to heal itself. The drugs are so toxic that the body must use its energies to try to eliminate or detoxify these poisons. In its weakened condition, the body becomes overcome by the toxins and permanent damage often results.
- Part I
- 1. Introduction
- 2. The History Of Cancer
- 3. What Cancer Is
- 4. Cancer Incidence
- 5. Normal Cells To Cancer Cells
- 6. A “Cure” For Cancer
- 7. The Seven Stages Of Disease
- 8. Can Cancer Be Prevented?
- 9. How Not To Develop Cancer
- 10. The Requirements For Health Will Fullfill The Needs Of The Sick
- 11. Habits
- 12. Cancer Treatment
- 13. Chemical Contaminants
- 14. Geographical Factors
- 15. Cocarcinogens
- Part II
- Part III
- Part IV
- Part V
- Part VI
- Part VII
- Questions & Answers
- Article #1: Autolyzing Tumors By Dr. Herbert M. Shelton
- Article #2: Some Prefer Cancer By Lewis E. Machatka
- Article #3: Black Pepper Causes Cancer!
- Article #4: Ten Commandments of Cancer Prevention