Why would two people with cancer receive different treatments? Patients often ask me this when they find out that they are being prescribed a medication that is different than the one that worked for their friend, neighbor, or co-worker who had cancer. The answer involves many incredible advances in cancer treatment, which I have seen progress in the 30 years I have been practicing oncology.
What is a cancer cell?Cells are the basic components of all of our organs. The liver is made of liver cells, the heart, of heart cells, and so on. There are two basic differences between cancer cells and “normal” cells. The normal cells that make up the organ or tissue know when to stop growing and multiplying. A cancer cell can also grow and multiply, but unlike a normal cell, it does not know when to stop. The result is a tumor, or lump, which is made up of this abnormal growth of cells.
The second difference between normal cells and cancer cells is that the cancer cells that make up a lump or tumor can travel to other parts of the body and start growing again. That’s what happened in the case of Elizabeth Edwards, whose cancer recurrence has been in the news lately. The original breast cancer cells that were found in October 2004 escaped from the breast and took up residence in one of her rib bones. This is not bone cancer, but breast cancer that has spread (metastasized) to the bone.
Cancer treatment in the pastIn the past, oncologists had very crude ways of stopping the growth of cancers. The drugs that stopped growth could not distinguish normal cells from cancer cells. So while the treatment worked wonders in damaging cancer cells, the unfortunate result was that it also damaged normal cells such as those lining the hair, mouth, and digestive system, and blood cells. This damage leads to the dreaded complications of chemotherapy -- hair loss, nausea and vomiting, and lowered blood counts and infection.
New discoveries in treating cancerToday, fortunately, we have learned a great deal about the chemicals (factors) in the body that can cause cancer to develop and grow. For example, normal breast tissue can grow under the influence of hormones such as estrogen or progesterone. Likewise, breast cancers can also grow under the influence of such hormones. One common way to stop their growth is to use drugs that block the effects of these hormones.
It’s been discovered that other chemicals (called growth factors) can also cause a cancer to grow. Different factors cause different cancers to multiply, and there are now drugs that specifically interfere or block these growth factors. We can test a cancer in the laboratory and determine if its growth is influenced by one of these factors. If so, the patient is often given one of the drugs that block that particular growth factor. Ten years ago, we were only beginning to understand these factors -- today we both understand them, and are administering drugs to patients to block them.
There are two other major advances that help us select drugs for patients with cancers. Most, if not all cancers, require the development of new blood vessels to nourish them. There are now drugs that can block the formation of these new, cancer-related blood vessels, thus denying the cancer the chance to thrive and survive. The second discovery is the understanding that there might need to be 10 or 15 chemical reactions in a cancer cell in order for it to grow. We now understand many of these chemical reactions and can treat patients with a drug that specifically blocks the chemical reaction (or reactions) that will stop their cancer cells from growing.
Personalized, targeted treatmentsAll of these discoveries are leading to a more “personalized” treatment approach for each patient’s individual cancer. In the past, we had much less information to decide what therapies would be best for a particular person at a particular time. Today, people with cancer are likely to get specific, tailor-made combinations of drugs that block the particular chemicals or factors that cause their individual cancer to grow.
Another important benefit of these newer treatments: they can “target” cancer cells, thereby reducing damage to normal tissues and helping to minimize the side effects that so notoriously characterized chemotherapy in the past.
So if you have been diagnosed with cancer, don’t be surprised if you get a treatment that’s different from that given to a friend. These differences represent all we have learned about cancer, and how to best treat it in individual people.
What have your experiences with cancer treatment been like? What about those of your friends and family? Tell me about them, and maybe I’ll use them as inspiration for future articles.
The main differences between cancer cells and normal cells are that cancer cells don’t know when to stop growing, and they can spread to other areas of the body. |
Marc Garnick, M.D., is an internationally renowned expert in medical oncology and urologic cancer, with a special emphasis on prostate cancer. He is a Clinical Professor of Medicine at Harvard Medical School and maintains an active oncology practice at Beth Israel Deaconess Medical Center. Dr. Garnick serves as Editor in Chief of Perspectives on Prostate Diseases, a quarterly report from Harvard Health Publications.
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Comments: 31
Thank you.
Is there any validity to the chemical reactions of excess salt and sugar, feeding cancer cells?
Many thanks.
I have a question... when the Doctor tells you you have a 'Carcinoid tumor' but they don't know it's point of origin... what exactly does that mean?
I have one patient who went in for supposed gall bladder infection and was then diagnosed with cancer and told it was a carcinoid tumor. I've looked for information on Medline Plus, the NIH library website but the most I can find is a very sketchy and ambiguous explanation that basically uses a lot of words to tell me nothing useful!
The poor woman is imagining the worst case scenario, pancreatic cancer, and I'd like to be able to provide her with some more usefull information to help calm her fears and give her some idea of what to expect.
I have a question about the state of growth factors research, as it pertains to developing more precise, specific ways to treat cancer on the cellular level. I've read that there is a relationship between cancer and adult bone marrow stem cells. Tumors contain growth factors and they utilize stem cells to help build the infrastructure they need (including fibroblasts and blood vessels). Are we closer to understanding how different types of tumors lure stem cells to the site of the tumor? And, is there any possibility of creating a mechanism for using those stem cells to stop the cancer?
You mentioned treatments which block the effects of hormones. With respect to estrogen sensitive tissues, I was wondering whether any SERMs (selective estrogen receptor modulators) other than tamoxifen and raloxifene were under development. Also, we hear a lot about SERMs for treating breast cancer and postmenopausal problems such as osteoporosis (e.g. raloxifene, which is purported to exert beneficial effects on bones, heart, and blood vessels without increasing a woman's risk of developing cancer), but how prevalent is the use of SARMs (selective androgen receptor modulators) in men? I know that GnRH agonists have been used to reduce testosterone levels in prostate cancer patients. Are SARMs being used in a similar fashion to block testosterone's negative effects on the prostate?
One last comment (which might be the inspiration for a future article) concerns the use of nanotechnology in cancer detection, diagnosis, prevention, and therapy. Nanotechnology has the advantage of multiplexing at the cellular level. It may shed light on the life cycle of the normal cell and the point at which molecular processes and changes within cells become correlated with the development of cancer.
A nanodevice of particular interest to me is the nanopore, which provides an improved method of reading the genetic code to help researchers detect errors in genes that may contribute to cancer. Nanopores (tiny holes that allow DNA to pass through one strand at a time) should make DNA sequencing more efficient. As DNA passes through a nanopore, the shape and electrical properties of each base, or letter, on the strand can be monitored. Since these properties are unique for each of the four bases that make up the genetic code, scientists can use the passage of DNA through a nanopore to decipher the encoded information, including errors in the code known to be associated with cancer.
Technologies such as this offer great hope of finding preventative strategies, as well as creating individualized treatment for each patient's cancer. One impediment to developing this type of technology is the difficulty of bringing physicists, engineers, biologists and clinicians together in a way that would allow them to work efficiently towards a common goal. I believe that nanotechnology could offer detection and diagnosis sooner than prevention or treatment, but it is difficult to determine how far off such technologies are from becoming a reality.
Thyroid cancer treatment is based often times upon the unique characteristics of thyroid cells. Because the thyroid gland makes thyroid hormone which contains the element iodine, often time thyroid cancer is treated with radioactive iodine. This is done because the thyroid cells, both cancerous and normal, can accumulate the radioactive iodine, thus concentrating a large amount of radioactive iodine in very close proximity or actually within the cancer. Other cancers or cells of other organs do not have this ability to accumulate radioactive iodine
Cancer cell certainly need nutrients to grow and nourish themselves, including the basic components of water, salt and sugar. They generally derive these through the creation of new blood vessels. Without these new vessels, the essential nutrients for both normal and cancerous cells growth cannot be obtained. Thus, the development of new drugs that block the formation of these new blood vessels are very promising, in that they actually "starve" the tumor of its needed ingredients.
Carcinoids are a rare type of cancer or tumor that resemble the more common type of cancers called carcinomas. Most often, they arise from the gastrointestinal tract (small bowel or appendix) a well as the lung, in so called bronchial carcinoids. They are often associated with the secretion of special chemicals, coming from the tumor. When these chemicals get secreted by the carcinoid, they get into the blood stream and may sometimes cause diarrhea or facial redness or flushing. Carcinoids are often diagnosed when patients present with symptoms thought to arise from the gastrointestinal tract. Further testing shows the abnormal tissue to be a carcinoid. Very commonly carcinoids can be cured by surgical removal; however, they may sometimes also spread or metastasize, requiring additional treatments in addition to surgery.
Mooclonal antibodies are being used more and more frequently for both the treatment of cancer as well as other diseases such as arthritis. Because we now have a better understanding about the chemicals and other factors such as receptors that allow a cancer to grow, we can now develop antibodies to block their growth. Monoclonal antibodies have been used extensively in breast cancer, where a specific receptor for growth (the Her 2 Neu receptror) can be "targeted" with a monoclonal antibody. Very encouraging results accompany the use of this antibody, called Herceptin. Other receptors that cause the growth of colon cancer or lung cancer have been targeted, and are now in clinical use.
In addition, the chemical substances on certain cancer cells, such as lymphoma cells (lymphoma is a cancer of the lymph nodes and the cells that normally make up a lymph node) can be targeted with a monoclonal antibody. The combination of the monoclonal antibody with the specific chemical has in the case of certain lymphomas resulted in excellent results in terms of cancer shrinkage and improvement in symptoms.
A large number of additional antibodies are also being actively investigated and we are likely to see many new advances in the months and years to come.
The whole scientific field that studies stem cells is very exciting but also early in terms of our understanding. Stem cells can populate the cells that eventually develop into an tissue or organ. Many cancer researchers are trying to determine if, during the development of a cancer, there is a specific stem cell that gives rise to abnormal growth, leading to tumor formation. We do not yet know if stem cells will be able to be used to stop cancers.
Normally, the bone marrow, is the site where red blood cells, white blood cells and platelets are manufactured. Each of these type of cells have at their origin a so called stem cell. Thus, the bone marrow has been the most studied organ in the body in which stem cells can be seen.
Of great interest is the presence of specific chemicals on the surface of stem cells. We can now, with very sophisticated laboratory testing, study certain cells and determine if they contain stem cells. We can also select these specific cells for further testing to try to get an understanding of what factors or chemicals make them grow and what makes them stop growing. We hope to apply this information to the development of drugs that will help cancer cells to stop growing.
Nanotechnology is indeed a very new and exciting field. You have mentioned several potential applications of nanotechnology. Nanotechnology may also be used to help target drugs to go to specific areas in the body. Nanoparticles that are fused with specific chemicals may also be used to improve the delivery of certain chemicals or drugs to areas that are not necessarily accessible. I know that we will be discussing in greater detail the use of nanotechnology in future postings on Gather.com
Thanks so much for your interest and for taking the time to write.
Lisa B,
We "Lisas" shouldn't be shy about using proper terminology ;-).
Lisa B. wrote: "Is there a reliable website which would list clinical trials for MAbs for lymphoma?"
If you want to look up clinical trial information for a patient, a good source would be the Clinical Trials database at the National Cancer Institute Web site. You can access it here: http://www.cancer.gov/clinicaltrials. Select "Advanced Search" after clicking on the link for "Find a Clinical Trial". This will allow you to refine your search by cancer type (e.g. Hodgkins or non-Hodgkins lymphoma), stage, type of trial, location, type of treatment (e.g. antibody therapy or antiangiogenisis therapy), drug name, phase of trial, etc. Maybe Dr. Garnick has other suggestions, as well.
Dr. Garnick,
Thanks for the informative reply to my questions. I look forward to reading articles detailing the use of nanotechnology in your future postings on Gather.com.
I apologize for not reading your article sooner, but it rings too close to home for my comfort level. I have lost three people I loved dearly to cancer. Each loss took a long time to heal and the most recent may never completely heal.
How much assistance do you believe stem cell research will be in eradicating cancer?
Monoclonal antibodies were mentioned. Dr Howard Weiner of Harvard U (Bringham & Women's Hospital) had been researching them. Do you know him? Has his research assisted in your quest?
Thank you so much for taking the time to write and I express my sympathies on your losses.
I believe that stem cell research is but one element of our multi-pronged attack on cancer. Such significant advances are occurring in terms of targeted therapies and the better understanding of stem cells and the biology of what makes stem cells do what the do will certainly go a long way helping us understand how best to apply these advances.
I believe that we all have a responsibility in helping with the ultimate eradication of cancer. Certainly the research that is coming from laboratories around the world is very imortant. However, I believe that all of us must appreciate that a significant amount of the cancer burden in this country could be lessened by behavioural changes by ourselves. The cessation of smoking, the elimination of the obesity epidemic, certain dietary changes, and the more stringent enforcement of hydrocarbon emissions are among a few that could make an important impact on the suffering caused by the very common cancers. Thus, I view the cancer problem as a global problem and the answers will come not only form stem cell research and other research and clinical advances, but also from changes in some of our less desirable habits.
Dr. Howard Weiner, a fellow faculty member at Harvard Medical School, is an internationally recognized expert in the field of multiple sclerosis. Much research from his laboratory has shed light to help us better understand the reasons why patients get multiple sclerosis, some of which includes work with antibodies. The wonderful thing about research on one disease is that many of the discoveries can be applied to other diseases. For example, drugs such as interferon which are very effective in one disease such as multiple sclerosis and hepatitis, may also be effective is certain types of cancers and cancers of the blood forming organs, such as leukemia. Thus, we are all working together, either directely or indirectly in our quest to better understant the mechanisms of disease and hope that discoveries in one can be applied to those of others.
Thanks again for writing.
To Isabella: Thanks so much for writing. The issue of chemotherapy side effects is an important one. Equally important to appreciate are the wonderful advances that have occurred in the past ten to fifteen years in modulating and lessening the side effects of chemotherapy. While in the past a patient may have been quite skeptical to receive chemotherapy because of anticipated side effects, the supportive measures that have now been developed include our ability to decrease the intensity and frequency of nausea and vomiting, decrease the likelihood of infections resulting from low blood counts, among others. We still have a great way to go, but progress in both the type of chemotherpy that is selected and the administration of treatments that make chemotherapy more tolerable has come a long way.
Marc B. Garnick MD