The Different types of cancer drugs
(Click here to go straight to our A-Z review of 90 of the most common cancer drugs.)
When we hear about cancer drugs, most of us immediately think of chemotherapy. But Pharmaceutical companies are trying to consign the word chemotherapy to the past. The bad press, the Weapons of Mass Destruction imagery, side-effects barely mentioned, poor results for certain cancers, ever cover ups and fraud cases. Life must move on.
And so there is now a whole range of different cancer drug treatments as cancer treatment options on offer to patients which are not chemotherapy and so do not act indescriminately against rapidly dividing cells, but are instead purpose built, tailor made and focussed, targeted, with purpose ranging from hormone therapies to substances that strengthen the bones (bisphosphonates) to drugs that work with the immune system. The latest anti-cancer drugs are called Biologics and we have an article specifically on those too!
The different kinds of treatments are described below.
"There is also a trend in cancer drug prescribing toward personalising treatments," says Dr Nicola Hembry, Director of Integrated Health Screening and specialist in environmental and nutritional medicine. "With the availability of chemo-sensitivity testing you can even discover before you begin whether the drug offered is going to work well with your type of cancer."
Other tests on the cancer cells themselves also reveal what type of drug will work best with the way your cancer cells are operating. Another example is with the use of the drug 5FU which has been found not to be useful for some people who have a deficiency in an enzyme called DPD which makes my body unable to metabolize and detoxify it. This is not yet tested for in the UK.
For historic reasons, there is a general belief that cancer drugs can have a horrible effect on the body and the side-effects can be worse than the cancer. Fortunately newer, more-targeted drugs come with reduced side effects.
And, while there still often are side-effects, there is a great deal that can be done to minimize them. (For example in Cancer Watch you will find research that shows ginger is good for reducing chemo-induced nausea.)
We state this because in the listing below, many (but possibly not all) of the common side effects are listed. THIS DOES NOT MEAN EVERY PATIENT IS GOING TO HAVE THEM. There are no absolutes about side-effects so please read the information below as a guideline, not a prophecy. Each of us is different and our bodies respond in different ways. But please, always discuss any potential side-effects with your doctor or one of the nurses before you begin treatment.
Different types of Cancer Drugs
General Chemotherapy Drugs
These can be referred to as alkylating agents, anti-neoplastics, anti-metabolites and although they might have different ways of doing it, they all act on the DNA to stop cancer cells reproducing. The reason they also have side effects is that they cannot differentiate between the cancer cells and normal cells. You might also hear of chemotherapy drugs being referred to as cytotoxic which means they are toxic to cells.
These generally have three purposes. First, they enhance a sense of wellness in people undergoing treatment boosting appetite, for instance. Second, they have some active benefits, for example with pleural effusion (fluid in the lung) and swelling in the brain around brain tumours where the drug dexamethosone is likely to be used. Third, they reduce the effects of chemotherapy. The drug used here in this instance is more likely to be prednisolone.
These are drugs which can help protect the bones against some of effects of cancer such as pain or weakness and are sometimes described as bone strengthening. They also raise the level of calcium in the blood. Drugs in this category include Clondronate (Bonefos), Ibandronic acid (Bondranat), Pamidronate and Zoledronic acid.
Cancer cells need hormones to grow, so there are a variety of drugs available to act on the production of hormones. In women the cancers that are hormone sensitive include breast, ovarian and uterine, while for men prostate cancer is hormone sensitive. Hormones are also thought to be implicated in other cancers such as melanoma.
Oestrogen and progesterone both affect some breast cancers. Tests will be done to find out whether you are sensitive to either of these. Hormone therapy will then be prescribed to stop the hormones getting to the breast cancer cells thus starving them of something they need to grow.
Aromatase inhibitors are one particular kind of hormone therapy. Aromatase inhibitors are a type of hormone therapy which blocks the growth of tumours by blocking the amount of oestrogen in the body. Although oestrogen is made in the ovaries, aromatase inhibitors dont stop the ovaries from producing it, but they can block other tissues from making it. Thus, they are most often used in women who have reached menopause.
They include anastrozole (Arimidex); exemestane (Aromasin) and Letrozole (Femara). There is a risk of bone loss with these treatments, but other drugs can be taken to mitigate this. Zoledronic Acid has been shown to be helpful with this.
Tamoxifen is another drug which prevents the growth of oestrogen-sensitive breast tumours but has a different action whereby it blocks the tumours ability to use the oestrogen.
A third type of hormone treatment focuses on the hormones made in the pituitary gland. This is a treatment used for women who have not yet had a menopause. Goserelin (Zoladex) and leuprorelin are examples of this. For men, goserelin for prostate cancer, leuprorelin and triptorelin prevent the testicles from making testosterone.
Anti-androgens are another type of hormone treatment for prostate cancer and include biculatamide (Casodex), cyproterone acetate (cyprostat) and flutamide (Drogenil).
Biological therapies / Immunotherapy
Biological therapies use substances that naturally occur in the body to destroy cancer cells. There are various different types described below all with different mechanisms,
Monoclonal antibodies :-Our bodies are naturally designed to fight infection through the production of antibodies which work with the immune system to recognise an infection if we are exposed to it again and help the body deal with it (hence they are used to make vaccines). Monoclonal antibodies are made from a single cell and work by recognising the protein on the surface of the cancer cell and then locking onto it, which then triggers the immune system to attack and destroying the cancer cell. Drugs that end in MAB are monoclonal antibodies that target the protein receptors on the cell. These would include alemtuzumab or rituximab. Other monoclonal antibodies which act by stopping cancer cells from taking up proteins and they would include trastuzumab (Herceptin); bevacizumab (Avastin) and cetuximab (Erbitux).
Another type of biological therapy is the cancer growth blockers that block or inhibit the enzyme tyrosine kinase. These are known as tyrosine kinase inhibitors (TKIs). Proteasome / Protease inhibitors are another type of growth blocker.
Drugs that end in NIB act within the cell blocking the messenger activity of the tyrosine kinase which is part of the signalling process within the cell. When this is blocked the cells cant divide and grow. Examples include Erlotinib (Tarceva), imatinib (Gleevec), gefinitib (Iressa), dasatinib (Sprycel) and sunitinib (Sutent).
Proteasome Inhibitors (PIs) work on the proteasomes that are found within all cells with the role of breaking down proteins. This makes them essential in a host of normal cellular processes like gene expression and message carrying. Research has shown that inhibiting proteasome activity in cancer cells seems to block cell proliferation and increase apoptosis or cell death. Currently bortezomib, which is usually administered intravenously, is approved in the USA for patients with resistant or relapsed myeloma. Hospitals such as Sloan-Kettering in New York have high hopes for PI drugs and are investigating Carfilzomib.
Interferon and interleukin are natural substances that are part of our immune system. They are now manufactured in large amounts and one of their functions is to stimulate the immune system to produce killer cells which will take on the cancer cells. Aldesleukin comes into this class of drug.
INDIVIDUAL CHEMOTHERAPY DRUGS
Click here to go to our A-Z review of the most common cancer drugs.