Breast Cancer May Spread Earlier Than ThoughtFinding Could Lead To New Approach To Treatment< June 11, 2003 >Individual breast cancer cells may escape from the original tumor and travel to other parts of the body at an earlier stage than originally thought, say researchers in a report in the medical journal Proceedings of the National Academy of Sciences (PNAS). This finding could change the way cancer treatment is approached, say experts. "It's definitely a new paradigm," says Dr. Christos Patriotis, an oncologist at the Fox Chase Cancer Center in Philadelphia. "There's always been a suspicion among scientists that advanced metastatic disease is not necessarily the same disease as the primary disease." The classic paradigm for cancer metastasis holds that cells in the primary tumor undergo a long series of genetic changes before leaving that tumor and heading off to other parts of the body. "So far, we have thought that probably the most advanced cell within the primary tumor will leave the primary site and found a metastasis," says study author Dr. Christoph Klein, of the Institut fur Immunologie, Ludwig-Maximilians Universitat in Munich, Germany. Experts Hail Findings, Want More AnswersBreast cancer is the most common cancer among women, excluding non-melanoma skin cancer. Currently, about 3 million women in the US are living with the disease, including 2 million who have already been diagnosed, and another 1 million who do not yet know they have the disease. The new research, which focused on breast cancer but could apply to other types of cancer, raises the possibility that there are actually two different routes by which the disease can spread: the classic one and this entirely new way. The idea could affect how physicians find metastatic cancer, which is cancer that has spread from one part of the body to another. "Many people are using primary tissue from the original breast tumor and exploring it, looking for indicators of spread," says Dr. Clifford Hudis, chief of the breast cancer medicine service, Memorial Sloan-Kettering Cancer Center in New York City. "And what this [the new research] says is the changes you find in that breast tissue cancer may, in fact, not be the full changes that you get when there's metastatic disease," Dr. Hudis says. "It is really interesting and it's not what anybody expected." Looking at Implications for Future Treatment"In most of the cases where there is a very clear in situ disease [one that has not spread], then the strategy is to have minimum surgery and treatment, as little as necessary," Dr. Patriotis says. "You treat the primary disease and ignore any other disease that has already escaped because you believe there is no such disease." But in breast cancer and also prostate cancer, there have been cases where the initial cancer is seemingly "cured," yet a secondary tumor develops years later. "We see cases where we treat the primary disease, we think that we are clean and out, then three to four years down the line we get relapses with metastatic disease," Dr. Patriotis explains. Ideally, the study authors say, treatment should take into account any differences between primary tumors and cells that have dispersed. "We think if you want to perform adjuvant therapy you have to know the characteristics of the target cells," Dr. Klein says. "Clinicians are administering drugs to patients to kill these [metastasized] cells but they don't know anything about them. That was why we decided to investigate these cells." Dr. Klein and his colleagues took bone marrow from breast cancer patients and analyzed individual cells that had migrated to the marrow from the primary tumor. The sample group included both patients whose cancer had spread or metastasized and those whose cancer was still localized. "We were quite surprised about the genetic findings," Dr. Klein says. "It seems that the cells leave the primary tumor very, very early. We found [the dispersed cells] had even less changes than the primary tumor, meaning they leave at an early stage of genetic development, even before the primary tumor has accumulated certain changes." The majority of these wandering cells will not develop into a tumor, but there is always that potential. "That's why time is against us," Dr. Patriotis says. "The longer you live and the longer you have those cells around, the higher the risk that cells will accumulate the necessary mutations and really take off to become tumors." Which is why it is vital to find them as quickly as possible. The results of this study may lead to new clinical practices, such as sampling bone marrow even when a patient has localized disease. "Their [the study authors'] point is that looking for genetic indicators of metastatic potential might not help us much right now because genetic changes might occur late in game," Dr. Hudis says. "We have to look differently." There may also be a drive to find new signs of single metastatic cells in patients with early-stage cancer, Dr. Patriotis adds. Researchers would then need to see if the drugs that are used on primary tumors will also be effective on these errant cells. "Companies that develop new therapies should try to validate whether or not their compounds can work on these cells," Dr. Klein says. "They cannot rely on the data of the primary tumor." Investigations are already under way to see if the same process is at work in other cancers, such as prostate cancer, Dr. Klein says. Always consult your physician for more information. |
For more information on health and wellness, please visit health information modules on this Web site. Risk Factors for Breast CancerWhat is a risk factor? A risk factor is anything that may increase a person's chance of developing a disease. It may be an activity, such as smoking, diet, family history, or many other things. Different diseases, including cancers, have different risk factors. Knowing your risk factors to any disease can help to guide you into the appropriate actions, including changing behaviors and being clinically monitored for the disease. What are the risk factors for breast cancer? Any woman may develop breast cancer. However, the following risk factors may increase the likelihood of developing the disease. Risk factors that cannot be changed:
The most frequently cited lifestyle-related risk factors:
Environmental risk factors: Exposure to pesticides, or other chemicals, is currently being examined as a possible risk factor. Estrogen replacement therapy and breast cancer: The safe use of estrogen replacement therapy, also known as hormone replacement therapy, has long been a topic of debate among medical experts. Estrogen replacement therapy has been in wide use among women during menopause to reduce the common symptoms associated with menopause. In 2002, the National Heart, Lung, and Blood Institute (NHLBI) halted a major clinical trial of the risks and benefits of combined estrogen and progestin in healthy menopausal women, due to findings of an increased risk of invasive breast cancer among its participants. The trial also found increases in risk of coronary heart disease, stroke, and pulmonary embolism. The study was scheduled to run until 2005. Always consult your physician for more information. Online Resources(Our Organization is not responsible for the content of Internet sites.) Centers for Disease Control and Prevention (CDC) National Cancer Institute (NCI) National Heart, Lung, and Blood Institute (NHLBI) National Institutes of Health (NIH) |
