By Joy Angelica Subido
Collateral damage. In contemporary parlance, this refers to negative incidental or secondary effects of a maneuver. But while in the past, this was customarily used in relation to military operations, its use has become colloquial so that it is now applied in relation to a variety of situations.
In the matter of breast and other types of cancers, the damage to surrounding healthy cells in the course of destroying the cancer cells may be referred to as collateral damage. Cancer treatment is a war against malignant cells where treatment modalities are dependent on the stage of the disease. Thus, it is expected that as the cancer becomes more advanced, stronger medicines are also employed. But because the usual oncology drugs are unable to distinguish between “good” and “bad” cells, all cells are harmed or destroyed during the course of treatment. Consequently, there is a magnification of negative side effects and deterioration of a patient’s quality of life.
Fortunately for some advanced breast cancer patients, targeted cancer therapy is now an option that can significantly improve survival rates. “The objective of targeted therapy is to stop the signaling system of cancer cells,” says Dr. Antonio Villalon, top medical oncologist and Cancer Institute director of the St. Luke’s Medical Center.
Dr. Villalon explains that targeted therapy entails interfering with the cellular processes of individual cells and depriving them of the signals for cancer activity. “Targeted cancer therapies are designed to slow or stop the growth of cancer cells. These types of therapies are more precise, so that there is less damage inflicted on surrounding normal cells.”
One such drug that acts on the principle of targeted therapy is Lapatinib, manufactured by pharmaceutical firm GlaxoSmithKline. By inhibiting tyrosine kinase, an enzyme in cancer cells that is identified as responsible for tumor growth, the drug slows down the course of the disease. Lapatinib was approved in first line, postmenopausal, hormone-positive, ErbB2-positive metastatic breast cancer therapy in combination with an aromatase inhibitor.
“This is a milestone drug that allows us the option of a non-chemo therapy regimen to select population of breast cancer patients,” says Dr. Villalon. He clarifies that not all breast cancers are responsive to targeted cancer therapy, and Laptinib is specifically indicated for the population positive for HER2/neu. “This is a tumor receptor status called human epidermal growth factor receptor 2,” Dr. Villalon elucidates. “Between 20 and 25 percent of the population who have breast cancer are HER2/neu positive.” The drug is the first and only oral treatment of its kind for this sector of breast cancer patients that significantly slows down the progress of advanced breast cancer in patients whose disease has progressed following treatment with other cancer therapies.
Although Dr. Villalon defers revealing the cost of the drug, manufacturer GlaxoSmithKline(GSK) has announced that the price of the targeted therapy drug Lapatinib is reduced by 40 percent under its Value Health program. Value Health was established in response to the need for more Filipinos to have access to high quality and affordable medicines.
The sad truth is that despite awareness drives, breast cancer continues to be diagnosed only when the disease has reached advanced stages. Statistics indicate that around six percent of breast cancers are metastatic upon diagnosis. This means that cancer cells have spread from a breast tumor to other parts of the body through the bloodstream or lymphatic system. The median survival time for women with metastatic breast cancer is placed at two to four years, with only one in five women surviving beyond five years. Definitely, ongoing efforts to promote breast cancer education and prevention need to be amplified and supported.
Dr. Cliff Hudis: Multi-Targeted Therapy Is Extending Non-Chemotherapy Options in Advanced Breast Cancer
ReplyDelete2011 Jan 4, Interview by L Scott Zoeller
Dr. Clifford A. Hudis is Chief, Breast Cancer Medicine Service, Memorial Sloan-Kettering Cancer, New York, NY.
OncologySTAT:In your view, which development in advanced breast cancer research that occurred in 2010 could have the most impact on oncology?
Dr. Hudis: I think that the big advances in breast cancer research are in targeted therapy, primarily those drugs that are targeting HER2, but also including, obviously, the Poly (ADP-ribose) polymerase (PARP) inhibitors and, potentially, others. This is a somewhat global answer to the question; however, the point I want to make, which is echoed not just in breast cancer but throughout solid tumor oncology, is that it is increasingly clear that many subtypes of individual malignancies are driven by either oncogenes or other narrowly activated targets. These, in turn, can be inhibited in order to treat these malignancies.
The global theme is continued expansion, if not an explosion, in the availability of viable targets for treatment development. This has, I think, the greatest potential impact on all of oncology, not just breast cancer. However, it carries with it a very obvious cost, which is we are going away from, as we have predicted for years we would, the notion of one disease universally consistent across patients.
It is becoming very clear that even people who have similar, if not identical, conventionally defined histologic types of cancer may indeed have molecular biology that is different. This is going to be a huge issue because the rarity of important targets across populations will make drug development increasingly challenging.
OncologySTAT: What specific changes in oncology have you observed or do you foresee as a result of this development?
Dr. Hudis: It is becoming increasingly clear that at least some patients with advanced breast cancer for some period of time may be able to obtain treatment that does not involve conventional cytotoxic chemotherapy. This is an advance in that it represents, at a minimum, a likely quality-of-life improvement, if not an effectiveness improvement, as well.
OncologySTAT: Could you put this development into historical perspective for the practicing oncologist?
Dr. Hudis: In terms of breast cancer, we have had targeted therapy in the form of hormone treatment dating back more than a century, starting with ovarian ablation and suppression. We more recently have had a second viable target, of course—HER2, targeted by trastuzumab. This is revolutionary, although it might not at first seem like it. By targeting these pathways in multiple ways, or by targeting them with more effective drugs, we are essentially able to extend the non-chemotherapy option to patients with disease other than hormone receptor–positive breast cancer.
Now, it is conceivable that we could have several lines of therapy for patients with HER2-positive breast cancers that are chemotherapy sparing, if not chemotherapy avoiding. It is conceivable that we could have even non-chemotherapy–containing regimens for triple-negative breast cancer; albeit, not tomorrow.
OncologySTAT: Would you sum up in a single sentence why you chose this development as the top story of the past year?
Dr. Hudis: We are in the beginning or maybe even middle of a long-awaited transition with functional, practical, and clinically relevant importance that is both redefining breast cancer and its treatment.
[...] A non-chemo therapy for breast cancer patients [...]
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