|
Hopkins News for You
This is a monthly service for our patients and friends around the world from Johns Hopkins International. To receive monthly reports via e-mail, please send e-mail to patientnewsletter@jhmi.edu.
February 2003
An Orange a Day?
Johns Hopkins Inaugurates Gamma Knife Center
Advances in the Treatment of Parkinson's Disease
The Importance of Experience in Sentinel Node Biopsy
Nagi Khouri, M.D., on Breast Cancer Diagnosis
An Orange A Day?
Here is a quick health quiz: What is one of the best dietary ways to control blood pressure? If you said lower sodium intake, you are half right. New studies suggest that adding another common dietary component can also help.
Johns Hopkins Internist Lawrence Appel, M.D., explains: "The diet that is high in potassium and low or reduced in sodium is the best diet for controlling blood pressure and preventing hypertension. It seems that an increased intake of potassium through foods blocks the effect of sodium in raising blood pressure."
Dr. Appel says potassium can be found in many vegetables and fruits. Bananas, oranges, orange juice, potatoes and pumpkin are great sources. Appel says the potassium may allow blood vessels to relax which in turn lowers blood pressure. Along with exercise and drugs, proper diet can help manage hypertension.
Johns Hopkins Inaugurates Gamma Knife Center
Johns Hopkins has completed a $4.5 million Gamma Knife Center for the non-invasive treatment of brain tumors and other neurological conditions.
The gamma knife, which is really not a knife at all, uses 201 beams of highly focused cobalt gamma radiation instead of a scalpel to painlessly "cut" through and destroy benign and malignant brain tumors, vascular abnormalities, and diseased areas of the brain without harming healthy tissue. It also provides an alternative for patients with tumors or abnormalities deep within the brain that cannot be reached through conventional surgery.
Although the entire process generally takes several hours, actual treatments last 15 minutes to an hour, depending on the size of the abnormality being treated. Patients usually return home the same day.
Advances in the Treatment of Parkinson's Disease
A new technique being used at Johns Hopkins helps diminish Parkinson's tremor, slowness and gait problems, and also dramatically cut the dyskinesia--periods of rigidity and slowness or inability to move--in patients with the disease. According to Hopkins neurosurgeon Frederick Lenz, the procedure, called deep brain stimulation, or DBS, also reduces many patients' medication needs. "They can function on less. One or two patients have gone off the drug altogether," he says.
In DBS, Lenz plots a path to the appropriate spot in patients' brains to stimulate, usually, the subthalamic nucleus. Locating the nucleus requires high precision, and the awake patient plays an active role in helping to pinpoint the target. Then, with the patient anesthetized, Lenz inserts and anchors a small electrode connected to a pacemaker-size neurostimulator he implants below the clavicle.
"The stimulation blocks the ability of target basal ganglia to fire, as though they have been lesioned.," says Lenz, who has performed over 200 DBS surgeries. A few weeks after the procedure, clinicians use telemetry to fine-tune the stimulation frequency, distribution, and voltage.
The Importance of Experience in Sentinel Node Biopsy
Sentinel lymph node biopsy--removal of one key lymph node rather than all of a woman's nodes to help determine the extent of her breast cancer--has become very popular in recent years. But how surgeons perform the procedure, and therefore the results they get, tends to vary with their experience.
Ted Tsangaris, M.D., Director of the Johns Hopkins Breast Center, has performed more than 400 sentinel node biopsies, and has done extensive research on various approaches and outcomes. The procedure, which involves injecting a blue dye and/or a mild radioactive material around the primary tumor in the breast, from where it travels to the lymph nodes, is not as easy as it sounds, he says.
Precisely when and where the tracer substance is injected influences the ease with which the sentinel node is identified. If injected too early, the tracer may have time to wander off to other nodes. If injected beneath the nipple or in overlying skin rather than around the breast tumor itself, the tracer may take an alternative route, bypassing the sentinel node.
"By not injecting the tracers correctly, you can end up looking at the wrong nodes," Tsangaris explains. Such errors account for a significant number of false-negatives in breast cancer diagnosis. Studies have shown that these wrong readings tend to occur early on in a physician's experience with SNL biopsy.
: Nagi Khouri, M.D., on Breast Cancer Diagnosis
Accounting for 1 out of 3 cancers diagnosed in women, breast cancer is still a devastating killer. In the United States, among cancers, only lung cancer kills more women every year. In the fight against breast cancer, early detection can still make the difference between life and death. To discuss the latest diagnostic tools available for early detention, we interviewed Dr. Nagi Khouri, Director of Breast Imaging in the Johns Hopkins Breast Center. A graduate of the American University in Beirut, Lebanon, Dr. Khouri has dedicated his efforts since 1986 to researching new breast imaging techniques and to educating other professionals in the latest imaging techniques.
What are the risk factors for breast cancer?
Dr. Khouri: At least 70% of breast cancers develop in women who have no known risk factor other than being a woman of advancing age. The occurrence of breast cancer starts becoming significant after the age of 40. Higher risk factors for the development of breast cancer include family history such as breast cancer in a first degree relative. A personal history of breast cancer or a biopsy proven high risk tissue from a prior surgical biopsy are other risk factors. Hormonal factors, postmenopausal hormonal therapy and diet may also play a role.
Why are mammograms so important?
Dr. Khouri: Mammograms allow early detection of breast cancer long before a woman or her physician can feel it. Using high quality mammography, expert interpretation and with the proper screening frequency, the mortality of breast cancer may decrease by as much as 50%. A number of studies carried out over the past 40 years, frequently with less than optimal mammography and with variable compliance by women, have shown a drop in mortality by factors ranging from 25 to 30%.
When and how often should women have mammograms?
Dr. Khouri: For the general population, several professional organizations in the United States recommend annual screening with mammography every year after age 40. The screening should consist of 2 views of each breast. High-risk individuals may need to start screening at a younger age. In addition, every woman should have an annual clinical examination of the breast by a health care professional and should be familiar with her breasts (breast self-examination). She should report any changes to her physician.
How reliable are mammograms?
Dr. Khouri: While mammography (traditional or digital) is the fundamental breast cancer screening tools it is important to remember that it is not perfect and that up to 15% of cancers may not be seen on a mammogram. Other imaging modalities are available to supplement screening in high risk individuals or complement mammography in certain situations, such as the detection of a mass felt on examination or seen on a mammogram, or to evaluate the extent of a suspected malignancy to better plan the optimal surgical procedures.
What are those supplemental imaging modalities for the breast?
Dr. Khouri: They include high resolution Breast Ultrasound (which is a fundamental part of breast imaging along with mammography), Breast MRI and Sestamibi Scintimammography for evaluation of the breasts. Also Positron Emission Tomography (PET scan) is used to evaluate possible regional lymph node involvement in patients with a known primary breast cancer as well as for evaluation of possible distant metastases. We also use the PET scan to monitor treatment response in patients with locally advanced breast cancer being treated with chemotherapy.
Can you tell us about the research your Division of Breast Imaging at Johns Hopkins is involved in?
Dr. Khouri: We are participating in a multi-institutional study to compare digital mammography to standard film mammography. We also are engaged in a study to evaluate the use of MRI in screening the contralateral breast in women recently diagnosed with breast cancer. Hopkins is also conducting a study to compare MRI and Whole Breast Ultrasound in breast cancer screening of very high-risk individuals.
What are the challenges to an effective breast cancer-screening program?
Dr. Khouri: These challenges are numerous. First at all, it is key that we inform and educate women about breast cancer and about the benefits of mammographic screening. Part of that education also involved updating and training physicians. Many nations lack a national policy for breast cancer screenings and there is a huge need for more screening and diagnostic centers.
Specialized training is also needed in order for technologists, radiologists and surgeons to perform their tasks well. The fight against breast cancer requires learning how to image the breasts, detect abnormalities, diagnose them and perfect the surgical techniques for the treatment of breast cancer.
What lessons can be learned from the Hopkins and American approach to the diagnosis of breast cancer?
Dr. Khouri: Breast cancer is a complex condition that requires the work of a team that includes the surgeon, the radiation therapist and the medical oncologist. But there are other members of that team who are also key and must be professionally trained and developed. I am referring to the social workers, the physical therapists and the psychologists who play a very important role in educating and supporting comprehensive care for our patients.
|
