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
 

What is Cancer?

Like all living things, the human body is made up of millions of cells. Each cell in our body has a specific form and role to play. For example, red blood cells take on the job of transporting oxygen. Likewise, liver cells are found only in the liver and cluster together to form the organ that we know of as the liver. For many years, medical science only understood the human body in terms of organs and their behavior. For example, we knew that liver cirrhosis happens when the liver starts to harden and becomes unable to do its job properly. In those days, cancer was thought of simply as lumps or growths in the body and treatment was by cutting the lumps out.

In the past twenty years, advances in molecular and cell biology have allowed us to understand how the human body works at the cellular level. For example, instead of just knowing that the liver filters our blood, we are now able to understand how the liver cells work together to regulate our blood, and also understand how liver cells organize themselves so that they become the organ known as the liver. It was with this medical knowledge that we now know that cancer happens when normal cells start to misbehave. All normal cells go through a life cycle; they are created, they multiply, and they die. This life cycle is regulated by a complex interaction of molecules in the body. At a molecular level, the body is essentially a complex universe of cells and molecules mingling with each other. When certain molecules come into contact with cells at certain times, they cause them to hibernate, multiply, or die. This series of interactions is what makes our bodies grow into our normal forms. Liver cells will organize themselves and only multiple enough times to gives us a liver of a normal size, likewise stomach lining cells will only multiple enough times to line our stomachs adequately. They will not "over-grow" and spill over into other organs or fill-up our stomachs.

Cancer Progression

Normal cells grow in an orderly fashion and die when they are supposed to. If the cells start to grow a lot, but are still dying when they are supposed to, then the condition is called Hyperplasia. This can happen when the body is fighting an inflammation, or during pregnancy. If cells start to multiply in a slightly uncontrolled fashion, then we may see the condition called dysplasia. This means that there are many more "young/immature" cells then there are "old/mature" cells. This can the start of a cancer, or it may just resolve itself over time. This can be detected if a biopsy is done on the suspected cells. However, if the cells continue to grow without control, then a cancer develops. This is known as a carcinoma. If the cells are still at the original area, then it is called carcinoma in situ. If the cancer cells have started growing into neighbouring parts of the body, then it is an advanced stage of cancer. Image source: Wikimedia Commons.

But sometimes cells get mutated and stop following their normal lifecycle. They either multiply uncontrollably, and/or refuse to die. The guardian cells in the body's immune system is sometimes able to detect the mutated cells. This causes a chain reaction that mobilizes immune system killer cells to destroy the bad cells through an action called lysing. But because cells can go bad in many ways (there are millions of ways for cells to mutate), some bad cells may take on a form that the guardian cells cannot recognize. The guardian cells may instead treat them as normal cells or normal molecules. In these cases, the bad cells have free reign to live forever and multiply without being attacked.

As the cells multiply, they clump together and form large masses known as tumors. The rate at which a tumor grows depends on how fast the cancerous cells multiply. This is also sometimes described as how aggressive the cancer is. In some cases, a series of reactions causes this to stop after a while, and the tumor becomes a benign growth, which isn't dangerous. But sometimes, the growth doesn't stop and keeps going on uncontrollably. This is when the tumor becomes malignant and the mutant cells are considered cancerous cells. Malignant tumors are dangerous because they grow uncontrollably. The growing tumor masses can squeeze normal organs until they are unable to function, or even grow into a healthy organ and disrupt its normal functions. It is similar to how tree roots can grow in a concrete pavement and cause the concrete to crack. Tumors are also dangerous because tumor cells feed off the nutrients that are in the body, which in turn weakens the body's organs. If the malignant growth is not stopped or controlled, the human body will eventually cease to function.

Cancer Metastasis

Image: How metastasis occurs. Source: Wikimedia Commons.

Cancer Growth and Stages
Cancers usually start out a some small part of the body, often in an organ. For example, colon cancer starts when a few colon cells become mutated and start to multiply uncontrollably. This usually causes a tumor mass to form in the organ itself. However, over time, the mass will continue growing until it "breaks out" of the organ and starts growing into the connective tissue or extra cellular matrix which sits between our organs and blood vessels. If it continues growing, it will eventually start pushing against another organ, or even break through the cells lining a neigbouring organ and start growing into the organ. As the tumor grows, it is not uncommon for some of the cancerous cells in the tumor to become dislodged and "fall off" the tumor. If these cells get into the blood stream or the lympathic system, then the cancer becomes a little more dangerous. The blood vessels in the body channel blood cells all over the body, so a cancerous cell that manages to get into this stream will be transported all over the body. Blood cells move very fast and blood undergoes lots of pressure changes as it moves through the heart and the blood vessels, and many non-blood cells will be destroyed by the hydrostatic pressure. But if the cell does survive, then it has a chance to lodge itself in another part of the body. To do this, it has to leave the blood vessels and break into the tissue surrounding the blood vessels or the tissue at another organ. This is often not a straightforward process, because the behavior of the cells and molecules at the new site are often very different from that of the cancerous cell's original site. But if the cancer cell has a behavior and properties that allow it to survive there, then it can start multiplying again and form a second tumor. The lympathic system is another system of vessels in the body that transmit lymph fluid. Cancer cells can likewise migrate to other parts of the body through this channel. Once cancer cells leave their primary site, the cancer is considered to have metastasized. Cancers that have metastasized are more difficult to treat, because they are now "floating in the blood stream" and can literally attach themselves anywhere. Simply cutting out a tumor through surgery will no longer solve the problem fully.

Cancer Terminology
As a matter of terminology, cancers are named according to the organ in which they first started. So for example, a cancer that started in the colon is called colon cancer. This name stays the same even if the cancer cells have spread to the liver. The cancer cells or tumor in the liver is simply referred to as colon cancer that has metastasized (moved, or displaced) to the liver. It is not called liver cancer.

 

 


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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.