Cancer Research

Chapter # 1 (Notes For Medical Students) 

What Is Cancer?

Cancer is a disease. In which a group of cells display uncontrolled growth and causes to destroy adjacent tissues of body.
According to an article in the Journal of the National Cancer Institute for April 17,1996, (Page 496505), there will be 1,359,000 cases of cancer, of all types, diagnosed this year. The article says that 80 percent of these cancers are preventable because they are due to four major factors: (1) Lifestyle, which includes smoking, diet and infectious agents; (2) Workplace which includes chemicals, fibers and radiation; (3) General Environmental contaminants in air, water and food; (4) Clinical and other medications and radiation. All of these factors combine with the patients age, gender, ethnicity, genetics, nutrition, immune function and any preexisting disease to cause cancer.
Frederica P. Perea wrote an article for the May 1996 issue of Scientific American Magazine titled Uncovering New Clues to Cancer Risk. She says that there are over 400 chemicals that have been shown to be carcinogenic in humans and animals. Many of these carcinogens are in our air, water, food supplies and the workplace. If we could eliminate environmental exposures, she estimates that cancer incidence could be reduced by90 percent.
There will be over 520,000 deaths due to all types of cancer this year. Most of those deaths could have been prevented if only the cancer had been detected early. The answer to cancer is early detection!.
Question:    Which are the most common cancers?

The Most Common Cancers

In 1996, there were over 240,000 cases of breast cancer detected. About 46,000 women died from it. There were 317,000 cases of prostate cancer and over 41,400 men died from it. There were over 170,000 cases of lung cancer that affected both men and women and about 150,000 deaths due to it. There were 152,000 cases of cancer of the colon and rectum that affected both men and women with 57,000 deaths due to it.
Just a few years ago, there were more incidences of diagnosed breast cancer than prostate cancer. This is probably due to the fact that there are two breasts, but only one prostate. But more men are now being made aware of prostate cancer and are concerned enough to get a check up. However there are still a large number of men who have the disease and are not aware of it. At least one man out of every ten over 50 has prostate cancer. For black men, the risk is even higher. One out of every eight black men over 50 will have prostate cancer. At this time, there are about 40 million men in the U.S. over 50. This means that there are over four million men with prostate cancer. For many of these men, the cancer will never become significant. Yet, it kills more men than the dreaded AIDS.
Before 1990, the incidence of diagnosed prostate cancer was about half what it is today. Even the number of men who died from it was much less. Before 1985, the primary method of prostate cancer diagnosis was by digital rectal exam (ORE). This is the test that the doctor does when he has you bend over and puts his gloved finger in your rectum. The prostate can be felt through the rectal wall. Today we have the prostate specific antigen (PSA) blood test which is much more accurate in detecting prostate cancer. So many more cases are being diagnosed. One reason more men are dying from prostate cancer today in spite of the early diagnosis, is because fewer men are dying from heart disease, lung cancer and other diseases. Many men are now living long enough for their prostate cancer to kill them.
There is no way that we know to prevent cancers, but most of them can be easily cured if they are discovered early. Usually a breast cancer or prostate cancer that is found early is fairly inexpensive to treat and cure. But if the cancer is not found until it has spread, it can be treated, but it is incurable. It is also very expensive to treat. Doctors can offer palliative treatments to ease the pain and to try to keep the patient as comfortable as possible. In many cases, even with metastatic cancer, the patient can live a fairly good life. Of course the quality of life can never be the same. We will say it again and again, the best way to fight cancer is an early checkup and early defection.

Family Risks

We have known for some time that there is a definite familial risk among close male family members for prostate cancer. There is about the same familial risk for women who have breast cancer and close family members. A study reported in the Journal of the National Cancer Institute, May 19, 1993, page 776, indicated that close female relatives of men who have prostate cancer have a high risk of getting breast cancer. It works both ways so male relatives of women who have breast cancer have a 40% to 50% higher risk of prostate cancer. Men over 40 should have a prostate checkup at least once a year. Women over 40 should have a breast cancer checkup at least once a year.
Women are fortunate in one way in that the breast can be so easily examined. Women should learn how to do a breast self examination (BSE) and do it every month. About 80 percent of breast lumps are not cancerous, but any lump should be suspect and should be checked thoroughly.
We could probably save a lot of lives if a man could check his own prostate, but it would be rather difficult to do a digital rectal exam on himself. But there is no reason why a man's wife or significant other could not do a check. Just use a bit of KY Jelly to lubricate the anus, then put on a surgical glove and feel the prostate. It should be smooth with no hard nodules. Of course an exam such as this would not be nearly as good as the educated finger of a good urologist, but it might detect the obvious cancers.
Question:    What is the Prostate gland?

The Prostate Gland

The prostate gland is part of the male reproductive system. Sperm is manufactured in the testes, then during ejaculation the sperm is forced up the vas deference vessels. The seminal vesicles and the prostate gland add a gelatinous nutritive component which is mixed with the sperm as they are ejaculated.
The normal prostate gland in a young man is about the size of a chestnut and weighs about 3/4 of an ounce or 21 grams. The prostate gland continues to grow throughout life, so in an older man it may be three or four times larger than the one found in a young man. The prostate gland is located just below the bladder. The urethra, or urinary canal, passes through it.
Just as the breast is the most common site for cancer in women, the prostate is the most common cancer site in men. Many of the 370,000 new prostate cancers that will be detected this year will be insignificant and may not require anything but to be watched and monitored.
The normal prostate cells produce a substance called prostate specific antigen (PSA). Normally it is a very small amount, about 2 to 4 ng/ml of blood. Because there are more cells in cancer, the PSA may go from 4 ng/ml up to well over 1000 ng/ml. The increased amount of PSA is easily detected in the blood.
In benign prostatic hyperplasia (BPH) there is an overabundant growth of normal prostate cells. These extra cells can also cause a rise in the normal PSA level, but the BPH cells rarely cause a rise above 10 ng/ml. Prostate cancer cells produce ten times more PSA per volume of tumor compared to BPH cells.
The prostate gland and cancer tests will be discussed in more detail later.
Question:    What are the terms used for cancer?

Cancer Terms:

There are several terms that you may not be familiar with. We have a comprehensive glossary in the Appendix. Here are a few of the common terms that we will be discussed.
Cancer: Cancer is the abnormal and uncontrolled growth of some of the cells in a body. About 90% of cancers are called carcinomas. Some of the others are called sarcomas, which are usually found in connective tissues; osteomas, or bone cancer; melanomas, or cancers from moles.
Tumor: Tumor is Latin, meaning a swelling. The oma in carcinoma is a Greek suffix that means tumor. So cancers may also be called tumors, but not all tumors are cancerous. Some tumors are benign growths that may not be life threatening.
We mentioned earlier that the first rule about cancer is that there are no rules. Quite often, but not always, the cancer will be a herd lump. Ordinary cells usually have spaces between them end the tissue that they form is rather soft. Many cancers are hard lumps where the cells are packed very close together.
A tumor may also be called a neoplasm. Neo is Greek for new and plasma Latin for form or mold. A neoplasm has come to mean a new and abnormal formation of tissue.
The term carcinoma is derived from the Greek karkinos which means crab. The term cancer is derived from Latin which also means crab. The ancient physicians of the Hippocratic school thought that the cancer they saw in their patients looked like a many legged crab. The grasping branches of the cancer that spread out reminded them of the claws on the crab.
Cancer is like a parasite. A parasite is an organism that lives within or upon a host. It contributes nothing to the benefit, welfare or survival of the host. Parasites may be such organisms as fleas, lice, tapeworms, fungi, bacteria, and viruses. Often the parasites will become so greedy that they will suck the life right out of the host. Cancer can do the same.
As long as a cancer remains encapsulated as a tumor, it may not be much of a problem, unless it is growing on or in a vital organ such as the brain. But it becomes an incurable problem when the cells begin to spread and metastasize. The cancer may send fingers out and invade nearby tissues. Or a few cells may break away and escape in the blood stream. These cells may then set up a distant colony. If the cells came from the prostate, then it will still be prostate cancer, even if it is located in the bones of the spine.
Angiogenesis: When you think about it, setting up a distant colony is a remarkable feat. This cell, or a few cells, float around in the blood stream, then find a suitable spot and settle down. A few cells can exist for a while by diffusion of nutrition from existing blood vessels. But as they multiply they need an ever increasing and constant supply of blood to bring oxygen and food for their voracious appetites. But the lack of blood vessels is not much of a problem for the pioneer cells. They simply secrete substances that are attracted to the nearest blood vessel. The substances cause the blood vessel to break through and create a new path to the metastatic colony. This is called angiogenesis. According to a study reported in the June 1996 issue of Contemporary Urology, Drs. Campbell and Bouck say that over 40 of these angiogenesisinducing compounds have been identified. Several studies are being done to try to find ways to counteract these compounds. If a way can be found to prevent angiogenesis, cancer could be conquered.
Oncologist: A doctor who specializes in the management or treatment of cancer. Onkos is from the Greek, which means tumor or mass.
Adenocarcinoma: Adeno means gland. Since the prostate is a gland, prostate cancers are called prostatic adenocarcinomas. An adenocarcinoma could occur in any gland, such as the adrenals, the thyroid or the pancreas. A gland is usually an organ or structure that produces and secretes substances that may be used in other parts of the body.
Chromosomes: Your body is made up of several trillion very tiny cells. The cells have a central nucleus which contains the chromosomes, protoplasm and other structures. The chromosomes carry the 100,000 genes that determine the characteristics of the person. There are various numbers of chromosomes in the cells of different plants and animals. In the human, there are 23 pairs. These pairs of chromosomes are called diploid, which simply means twofold. Diploidy means that the cells have two sets of homologous chromosomes. Homologous means that they are similar, such as your two hands are similar.
Some cancer cells do not have the characteristic pairs of chromosomes. Some of them may be aneuploid, (the prefix an means without or not, eu means good), which means that the cells are not good and do not have the normal pairs of chromosomes.
A single cancerous tumor may have several different ploidy types of cells. Ploidy tests can be done on biopsied material from a tumor to determine the ploidy. Those tumors that have a high percentage of aneuploidy usually have a poor prognosis.
Carcinogens: We know that there are over 400 chemicals, toxic materials and carcinogens that contribute to the cause of cancer. For instance, we know that many people who smoke are going to die of lung cancer. But everyone is different. There are some people who smoke enough cigarettes to kill an elephant, yet they do not get cancer.
We know that radiation can cause cancer. We know that the ultraviolet rays of the sun can cause skin cancer. We know that some viruses can cause cancer. We know that injuries, constant abrading of tissues and many other things can cause it. We also know that some people are more predisposed to cancer than others. These people have inherited oncogenes (genes predisposed to cause cancer), from their parents and ancestors that put them more at risk for many types of cancer. If your parents or close blood relatives have had cancer of any sort, make sure that you have proper checkups. We will say it again and again, most cancers can be cured if detected early enough.