Cancer Doubts .com
  Information for patients researching their options

Learn about cancer and
Talk to your doctor with confidence

  Cancer information  

 
         
 Contents
01 What is cancer?
02 Cancer symptoms and screening (how cancer is detected)
03 Causes of cancer
04 Can cancer be prevented?
05 Cancer Stages
(how long do patients live?)
06 Cancer treatment and therapy (how cancer is treated)
07 Types of doctors who treat cancer
08 Choosing a doctor (or getting a second opinion)
09 Preparing for Chemotherapy and Radiotherapy
10 Cancer support (patient psychology and feelings)
11 Cancer suport - How friends can help
12 Is it important to do my own research? (or do I just follow doctor's orders)
13 Cancer information (research your treatment options)
14 Alternative and complementary treatments for cancer
15 Avoiding dubious treatments
16 How medical research is done (how to read medical research papers)
A About this site
 

How is cancer treated?

The goal of cancer treatment is to kill or inactivate all the cancerous cells in the body. There are few ways that this can be done: (1) cut out all the cells through surgery, (2) by using using radiation to destroy ("zap") the cancerous cells, (3) by taking medicine (injected or oral) to put molecules in the body that can cause the cancer cells to die, and (4) by getting the immune system to recognize the cancer cells and triggering the immune system's NK-cells and T-cells to kill the cancerous cells.

The choice of treatment method depends on the nature of the cancer, the location of the cancerous tumor, and how far the cancer cells have spread. Sometimes doctors will combine different treatment methods to control a cancer.

 

(1) Surgery - This is the most straightforward way to address a cancer - a surgeon operates on the patient to cut out a tumor. This is practical only if the tumor can be safely removed without destroying the organ's ability to function. For example, small tumors in the colon can usually be removed through surgery because cutting a portion of the colon won't affect the overall ability of the body to function (there is about 5 feet of colon in the body, and the colon is like a pipe which can be cut and rejoined). Surgery isn't practical in cases where the tumor cannot be removed without destroying the organ. For example, in some stomach cancers, instead of growing polyp like tumors which can be cut off the stomach, some cancer tumors grow as diffuse tumors where they spread out and grow along the surface of the stomach. In such cases, it is can be very difficult to remove the tumor without destroying the stomach.

If the cancer has not grown out of the original host organ and is still within its boundaries, (ie. stage 1 cancer), then surgery can potentially be a cure for the cancer. There is a good chance that the cancerous cells are only in the tumor and nowhere else, so removing the tumor through surgery can potentially remove all the cancerous cells from the body. However, if the cancer tumor has already grown out of the original organ (stage 2, 3 or 4) cancers, then surgery would only be a temporary stop-gap measure. Removing the primary tumor would help to reduce the tumor burden on the body (less stressful for the body), but there is a high possibility that cancer cells are already present in small numbers elsewhere in the body. The problem is that there are probably millions of the cells circulating in the body, and many of them would just be small groups of cells that are not visible as tumors. It would be impossible for surgery to find and remove all of them (they may also be in the blood stream). Nonetheless, where possible, doctors will often recommend removing the primary tumor first, just to reduce the tumor burden on the body and "buy time" to try other treatments.

 

Gamma Knife Radiosurgery

Image: A Gamma Knife radiotherapy machine, used to treat cancer tumors in the brain. The patient lies on the bed and the patient's head is secured by a frame. High energy raditation beans are then projected into the brain to kill tumor cells. Source: Wikimedia Commons, used under the GNU license.

(2) Radiotherapy (or radiation therapy) - this refers to the use of radiation to kill cancer cells. There are two ways this can be done: (1) using a machine to project radiation beams into the body, or (2) injecting or putting small bits of radioactive material in the body near the tumor. Projecting radiation from an external machine is commonly done to destroy cancer cells that are difficult to remove surgically. It is also used in some cases where a primary tumor has been removed surgically, to radiate the area around the primary tumor. This is done in the belief that the radiation will destroy and remaining cancer cells that may have been left behind in the general area after the main tumor was removed. (Cancer cells are very small and cannot be seen by the naked eye, nor can they be seen by CT scans. Even if there is no visible tumor in the body, it is possible that small clusters of cancer cells may be present) The key drawback to radiotherapy is that the radiation also kills normal healthy cells. In effect, the patient will get some degree of radiation burn when radiotherapy is used. This can cause bleeding, peeling skin, pain and other effects associated with exposure to radiation. Doctors have to look at each patient's case carefully, to make sure that radiation therapy won't cause more harm than benefit.

In cases where cancer cells have already spread into the bloodstream or lympathic system (i.e. metastatic cancers, stage 4), then radiation therapy is often not used because its side effects far outweigh its benefits. Since the cancerous cells are already "running around" the rest of the body and in the bloodstream, radiation therapy to a particular spot on the body won't do much good.

 

(3) Chemotherapy - this refers to taking medicine to control cancerous cells. Depending on the medicine being used, it may be either injected (intravenous) or taken orally. Apart from injecting chemotherapy medicine in through the arm, some medicines may need to be injected through blood vasculature somewhere else in the body (e.g. near the heart). This is usually done either because because medicine would overload the relatively small blood vessels in the arm, or to deliver the chemotherapy closer to the tumor's location. In these cases, Instead, a tube needs to inserted into a vein near the heart where the blood vessels are stronger, and the chemotherapy medicine injected in through the tube. As a result, many chemotherapy patients have some form of catheter surgically installed so that chemotherapy can be delivered regularly.

Chemotherapy treatments usually take place in cycles. (The exact duration and nature of the cycles depends on the medicine being prescribed). A common cycle is 3-week cycle, where a patient is given chemotherapy for a 1-3 day period, then waits for 3 weeks before the next dosage is delivered. For injected chemotherapy, each chemotherapy session may last up to 4-5 hours, as the medicine is slowly dripped (IV drip) into the body. Some medicines may need to be delivered slowly over a 24-48 hour period. In such cases, the patient is given a portable pump to be worn until all the medicine has been injected into the body.

Chemotherapy medicine tries to destroy cancer cells in one of the following ways:
(1) by attacking all cells that are undergoing multiplication - because cancer cells multiply very often, it is hoped that this attack will disable them as they try to reproduce. The side effect is that many normal cells in the body also undergo regular reproduction. For example, the cells in your mucus membrane in the mouth and throat and regularly renewed - old cells die and new cells are created through cellular division (mitosis). This type of chemotherapy medicine will affect these cells too, leaving patients prone to mouth ulcers and other side effects.

Antibody

Image Above: An antibody molecule. The Y-shaped variable end is like a jigsaw puzzle piece. It attaches itself to other molecules or cells in the body. In the case of cancer therapies, the variable portion is created in a shape that allows it to connect to certain parts of cancer cells. The other side of the antibody molecule can attach to other molecules, such as immune system cells, in the body. In a sense, an antibody molecule is like a matchmaker - it attaches to one thing on the straight side, then attaches to something else on the Y-side, thus bringing two molecules/cells together. Image Source: Wikimedia Commons.

Image Below: Antibody molecules attaching themselves to a tumor cell. Some of the antibodies shown are being used to bring radioactive molecules to a cancer cell to kill it. Others just attach themselves to the tumor cell so that certain cellular signals are not received by the tumor cell.

Antibodies Attaching to a Tumor Cell
 

(2) by preventing cancerous cells from receiving signals or sending "kill yourself (apoptosis)" triggers to cancerous cells. Recall that cancer cells, like all cells, react to ligand molecules that bind to receptors on their surface. These ligand molecules can trigger the cell, through cell signaling pathways, to do certain things, like grow, or die. Some chemotherapy medicine are specially designed molecules which can connect to certain receptors on the cancerous cells, and either trigger them to die, or prevent other ligand molecules from connecting to them and triggering them to continue duplicating. For example, many colon cancer cells have an excess of Epidermal Growth Factor receptors (EGFr) on their surface, and normal EGF and Transforming Growth Factor-alpha molecules in the body bind with these receptors and trigger the cancer cells to continue growing. The chemotherapy drug Erbitux (cetuximab) is a molecule that binds to these EGFr receptors, thus "plugging them up" and preventing the other normal molecules from connecting to the receptors. This prevents the cancer cells from being triggered to continue growing. Many such chemotherapy medicines are known as monocolonal antibodies because their molecules are similar in principle to antibodies manufactured by our own bodies.

(3) by preventing cancer cells from forming tumors. Remember that cancers usually only become fatal when they grow into large tumors which destroy an organ's ability to function. So, a medication that tries to prevents clusters of cancer cells from becoming a tumor might be able to prolong life. Strange as it sounds, but tumors are like a mini-organ which need to have blood vessels growing into them, so that they can receive nutrients and remove waste. To trick the body's normal blood vessels into growing an extension into the tumor, cancer cells secrete VEGF protein molecules. When these molecule come into contact with VEGF receptors on normal blood vessel cells, they cause the blood vessel cells to extend the blood vessel (like a new tree branch) into the tumor. Chemotherapy medicines like Avastin (bevacizumab) try to prevent this. Avastin is a ligand molecule that binds to the VEGF receptors on regular blood vessel cells without causing them to grow. In effect, they are "plugging the receptors" so that VEGF protein molecules from the cancerous cells cannot connect to them. As a result, the tumor is unable to attract a blood vessel to grow into it, and is unable to get nutrients which it needs to grow bigger. An interesting side effect of Avastin is that it also causes the existing blood vessels in the tumor to "straighten out". This makes it easier for other chemotherapy medicines to get into the center of tumors and start killing cancer cells at the center of the tumor.

As with all medications, chemotherapy has side effects. Side effects depend on the medicine being taken, but common side effects include feeling numbness in the extremities, memory loss, nausea, hair loss and fingernails turning dark purple. Doctors can usually prescribe other medications to counter side effects like nausea, but you should always tell the doctor about the side effects you are experiencing. Most side effects are non-fatal and expected, but some may be an indication of a more serious problem occurring in the body and your doctor is the best person to make that assessment.

All chemotherapy medicines also carry a small, but definite risk of a fatal allergic/hyper-sensitivity reaction. For example, the drug oxaliplatin which is based on platinum, is known to cause a fatal reaction in some patients. So some medical protocols call for a doctor to be present the first time such a drug is injected, in case a dangerous reaction occurs.

 

Immunotherapy Macrophages attacking Cancer

Image: Macrophages, a type of cell that makes up the immune system, attacking a cancer cell. Source: Dr. Raowf Guirguis. National Cancer Institute.

(4) Immunotherapy - this refers to the process of getting your body's immune system to recognize the cancer cells and start attacking them. There is a belief among many in the medical research community that immunotherapy holds the best promise in finding a cure for cancer, because the immune system can potentially hunt down and destroy every last cancerous cell without causing too much damaging side effects. Immunotherapy is a relatively new area in research terms, and there are new developments coming out very often. The Stanford Cancer Center (link on the right) is one of the main centers for this type of research, and I encourage you to explore their website. The idea behind immunotherapy is to get the immune system to detect the cancerous cells. In many cases, the surveillance cells in the immune system treat cancerous cells as normal cells, and do not initiate an attack to kill them. It is not entirely understood why this happens. Some attempts to make cancerous cells recognizable are to inject monoclonal antibody molecules which can bind to cancerous cells with one side of the molecule, and leave another side of the molecule on the outside of the cancerous cell. The exposed side of the molecule would ideally be something that makes the immune system see the cell as dangerous, and get it to attack and kill it.

Another approach has been to get the immune system to go into a heightened state of alert, so that it will see cancerous cells for what they are. It is thought that some molecules in foods like certain mushrooms can make trigger the immune system into a higher state of alert, because of beta-glucan molecules that exist in many mushrooms. It is theorized that some beta-glucan molecules may look like the outer coatings of dangerous bacteria, and when the immune system sees them, it goes into a high-alert state. Researchers at Memorial Sloan Kettering's Integrative Medicine Service have or are conducting trials of certain foods/herbs like Maitake mushrooms, Astragalus and Ashgawandha to see if they affect the immune system this way. (The link is on the right)

I would advise you to tell your doctor if you are taking any supplements or herbs for this purpose. All such foods can have potential side effects which can interfere with your chemotherapy. For example, grapefruit is known to reduce the effectiveness of many forms of chemotherapy. All foods have bio-active compounds that interact in some way with medicines and your body's molecules. Just because something is natural doesn't mean it won't cause any unintended side effects when it is taken with medicine.

 

Book recommendation: I highly recommend the book "Chemotherapy and Radiation Therapy Survival Guide" for anyone who has to undergo chemotherapy or radiation therapy. It explains the effects on patients from a nursing perspective. I found it extremely useful to know beforehand what the treatement entailed. Nothing beats being prepared - it is a exhausting and potentially painful treatment, and being prepared helps a lot. The link to the book is on the right hand side bar of this page.

 

 


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Medical information for cancer I am not a medical professional; please consult your doctor for a medical opinion. This is my attempt to explain cancer to anyone who is affected by it. If this site helps just one person, then it will have served its purpose.

 

 
 Cancer Links
Prominent research and treatment centers
Stanford Cancer Center
Memorial Sloan Kettering
M.D. Anderson Cancer Center
Kimmel Center at Johns Hopkins
Dana-Farber/Harvard
Mayo Clinic
 
Information on Drugs
Drugs at FDA
NCI Drug Info
 
Complementary and Alternative Medicine Information
Sloan Kettering
(Integrative Medicine Service)
Medline Plus
American Cancer Society
PDR (Herbals and Supplements)
 
Complementary Medicine and Supplement Suppliers
Cuesta Agaricus Mushrooms
Agaricus Farm Mushrooms
Mitobi Mushrooms
Freshes Mushrooms [Bulk]
AllStarHealth [Maitake D-Fraction]
Maitake Products [D-Fraction]
LifeStream [BRM 360 capsules]
Himalaya Herbals [Ashwagandha]
Vita Green [Yun Zhi extract]
 
Clinical Trials
Clinical Trials (NIH)
 
Research Papers
National Center for Biotechnology Information
Google Scholar
 
New Drug Approvals / Drugs in the pipeline
FDA approvals
 
Helpful Books and Sites
Chemotherapy and radiation therapy survival guide
Cancer Guide.org
The biology of cancer
 
Patient Stories
Andrew Grove
Steve Dunn

 


 

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Site Copyright © 2008 Wei-lung Wang. Top banner images from the Wikimedia Commons, and used under the terms of the GNU General Public License.