Chemotherapy Treatment Options for Breast Cancer
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Experts agree that for most breast cancer cases, chemotherapy is not the first treatment of choice. But for those for whom it is appropriate, it can provide effective, long term results.
Chemotherapy consists of using drugs to combat cancer. With the increasing sophistication of pharmacology, those drugs are safer, more effective and more targeted, with fewer side effects than ones of the past. Today, it’s common to use a drug ‘cocktail’ in order to offset side effects and provide a more effective treatment.
The drugs used typically interfere with the cells’ ability to divide, since that is one of the chief characteristics of cancers, an uncontrolled growth from abnormal cell division in breast cancer tissue.
Chemotherapy is often chosen when the cancer has become more advanced, requiring more a rigorous response to eradicate cancer cells. Cancer cells clumps can grow and metastasize (spread of a primary tumor to other areas, forming secondary tumors of similar type). That condition may indicate that chemotherapy is an appropriate regimen.
Cancers can recur. The causes are still poorly understood. In some cases it may be that the initial cancer wasn’t entirely eradicated. Or, it may be that the underlying cause that generated the tumor is still present and active, causing the cancer to regenerate. But whatever the basic reason, chemotherapy is often used in such cases.
But one of the more serious complications with chemotherapy treatments is related to its side effects. Though the drugs are improving in this regard, chemotherapy treatments sometimes affect healthy cells as well as cancerous ones. That results in healthy systems being harmed and lessened in function.
Since some of that function is to fight disease such as the cancer itself, a double harm occurs. Radiation therapy has a similar drawback in that it compromises the immune system, which is part of what helps to fight the cancer and its effects.
The digestive system is often affected in negative ways, leading to nausea, common among those undergoing chemotherapy treatments. Hair loss is a by-now familiar effect. But chemotherapy can even affect the composition of bone marrow, which leads to a number of harmful effects. Bone marrow performs several functions in the body. Foremost among them is aiding in the production of red and white blood cells.
Damage to heart, kidney and other organs is possible, though this is uncommon since cells in these organs don’t divide as frequently under natural circumstances. In some studies, memory and concentration loss were associated with chemotherapy treatments. Older female patients often find the reproductive cycle altered, bringing on premature menopause. ‘Female patients’ is specified here since men, too, can contract breast cancer.
Still, drugs in use today are better tolerated and more targeted that those of previous generations. They may help cut off vessels that supply blood to the tumors which encourage the growth of just such vessels to feed themselves. There are a variety of chemotherapy regimens, with each one designed for the individual patient and his or her circumstances.
Though never pleasant, chemotherapy provides an important tool in the fight against what was once an almost always fatal disease. Today, long term survivability is greater than ever with fewer long-term side effects. Chemotherapy is one of the reasons.
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Breast Cancer Symposium 2008
Direct anti-tumor and anti-vascular effects were studied of Tykerb, Nexavar and Avastin in fresh biopsy specimens of breast cancer and presented at the American Society of Clinical Oncology Breast Cancer Symposium on September 5, 2008.
While the other clinically-available ‘nib’ drugs have been shown to have anti-vascular activity, anti-vascular activity of Tykerb has not been previously reported.
Angiogenesis studies are limited by the clinical relevance of laboratory model systems. They don’t do “real world” studies under “real world” conditions. Patient outcomes need to be reported in real-time, so patients and cancer physicians can learn immediately if and how patients are benefiting from new drug therapies.
Cell culture detection of microvascular cell death in clinical specimens of human neoplasms and peripheral blood can identify the activity of both single drugs and combinations of drugs at the level of individual patients with individual cancers. It works by measuring drug effects (real-time) upon endothelial cells which make up blood vessels.
Drugs like Avastin had striking anti-microvascular effects but minimal anti-tumor effects. Tarceva and Gleevec had mixed antitumor and anti-microvascular effects. Anti-microvascular effects of Tarceva and Iressa were equal to those of Sutent and Nexavar. Anti-microvascular additivity was observed between Avastin and other drugs on an individual basis.
Conclusions of the study had shown that Tykerb has antivascular activity superior to that of Nexavar. Avastin + Tykerb may be the first clinically-exploitable antivascular drug combination. High dose, intermittent ‘bolus’ schedules of Tykerb to coincide with Avastin administration may be clinically advantageous, even in HER2-negative tumors.
The system utilized for the study was a functional profiling assay, which may be used to individualize antivascular therapy. It can be adapted for simple, inexpensive and sensitive/specific detection of tissue and circulating microvascular cells in a variety of neoplastic and non-neoplastic conditions, for drug development, and individualized cancer treatment.
The cell-based assay can accurately sort drugs into categories of above average probability of providing clinical benefit on one hand and below average probability of providing clinical benefit on the other hand, based both on tumor response and patient survival.
Poster: www.weisenthal.org/Weisenthal_ASCO.pdf
Source: Weisenthal Cancer Group
In chemotherapy selection, Gene and Protein testing examine a single process within the cell or a relatively small number of processes. The aim is to tell if there is a theoretical predisposition to drug response.
Functional Profiling tests not only for the presence of genes and proteins but also for their functionality, for their interaction with other genes, proteins, and processes occurring within the cell, and for their response to anti-cancer drugs.
Genes create the blueprints for the production of proteins within the cell. A protein is a molecule that makes a cell behave in a certain way. It does so by interacting with other proteins in a complex series of steps.
The goal of Gene testing is to look for patterns of normal and abnormal gene expression which could suggest that certain proteins might or might not be produced within a cell. However, just because a gene is present it does not mean that an associated protein has been produced.
Protein testing goes one step further by testing to see if the relevant protein actually has been produced. However, even Protein testing cannot tell us if a protein is functional or how it will interact with other proteins in the presence of anti-cancer drugs.
Gene and Protein testing involve the use of dead, formaldehyde preserved cells that are never exposed to chemotherapy drugs. Gene and Protein tests cannot tells us anything about uptake of a certain drug into the cell or if the drug will be excluded before it can act or what changes will take place within the cell if the drug successfully enters the cell.
Gene and Protein tests cannot discriminate among the activities of different drugs within the same class. Instead, Gene and Protein tests assume that all drugs within a class will produce precisely the same effect, even though from clinical experience, this is not the case. Nor can Gene and Protein tests tell us anything about drug combinations.
Functional Profiling tests living cancer cells. Functional Tumor Cell Profiling assesses the net result of all cellular processes, including interactions, occurring in real time when cancer cells actually are exposed to specific anti-cancer drugs. Functional Tumor Cell Profiling can discriminate differing anti-tumor effects of different drugs within the same class. Functional Profiling can also identify synergies in drug combinations.
Gene and Protein tests are better suited for ruling out “inactive” drugs than for identifying “active” drugs. When considering a cancer drug which is believed to act only upon cancer cells that have a specific genetic defect, it is useful to know if a patient’s cancer cells do or do not have precisely that defect.
Although presence of a targeted defect does not necessarily mean that a drug will be effective, absence of the targeted defect may rule out use of the drug. Of course, this assumes that the mechanism of drug activity is known beyond any doubt, which is not always the case.
Although Gene and Protein testing currently are limited in their reliability as clinical tools, the tests can be important in research settings such as in helping to identify rational targets for development of new anti-cancer drugs.
As you can see, just selecting the right test to perform in the right situation is a very important step on the road to personalizing cancer therapy.
Literature Citation: Eur J Clin Invest 37 (suppl. 1):60, 2007