Prostate Cancer (cont.)
Kevin C. Zorn, MD, FRCSC, FACS
Gagan Gautam, MD, MCh
William C. Shiel Jr., MD, FACP, FACR
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
Dennis Lee, MD
Dennis Lee, MD
Dr. Lee was born in Shanghai, China, and received his college and medical training in the United States. He is fluent in English and three Chinese dialects. He graduated with chemistry departmental honors from Harvey Mudd College. He was appointed president of AOA society at UCLA School of Medicine. He underwent internal medicine residency and gastroenterology fellowship training at Cedars Sinai Medical Center.
In this Article
Can prostate cancer be prevented?
No specific measures are known to prevent the development of prostate cancer. At present, therefore, we can hope only to prevent progression of the cancer by making early diagnoses and then attempting to cure the disease. Early diagnoses can be made by screening men for prostate cancer with PSA and digital rectal examination The purpose of the screening is to detect early, tiny, or even microscopic cancers that are confined to the prostate gland. Early treatment of these malignancies (cancers) can stop the growth, prevent the spread, and possibly cure the cancer.
Based on some research in animals and people, certain dietary measures have been suggested to prevent the progression of prostate cancer. For example, low-fat diets, particularly avoiding red meats, have been suggested because they are thought to slow down the growth of prostate tumors in a manner not yet known. Soybean products, which work by decreasing the amount of testosterone circulating in the blood, also reportedly can inhibit the growth of prostate tumors. Finally, other studies show that tomato products (lycopenes), the mineral selenium, and vitamin E might slow the growth of prostate tumors in ways that are not yet understood.
Recently, studies have shown that certain medications (finasteride [Propecia] and dutasteride [Avodart]) decrease the chances of getting prostate cancer when taken over the long term. These medications are currently used for shrinking the size of the prostate and relieving symptoms associated with benign (non-cancerous) enlargement of the prostate. However, they may have a future role for decreasing the chances of development of prostate cancer in men who are at high risk for the disease.
What will be the future treatments for prostate cancer?
The treatment of organ-confined prostate cancer to date has involved cutting out, radiating, or freezing the gland in trying to cure the disease. In more advanced cases, the goal has been to control the cancer for at least some time by using hormonal treatment or chemotherapy. Earlier diagnosis and improved treatment techniques in recent years have certainly led to better results.
The key to curing prostate cancer, however, ultimately will come from an understanding of the genetic basis of this disease. Genes, which are chemical compounds located on the chromosomes, determine the characteristics of individuals. Accordingly, investigators at research centers have focused on identifying and isolating the gene or genes responsible for prostate cancer. For example, studies are being conducted in men who have a family history of prostate cancer to try to uncover the genetic links of the disease. The investigators ultimately will try to block or modify the offending genes so as to prevent or alter the disease.
Recently, the FDA approved a prostate cancer vaccine called sipuleucel-T (Provenge) that has been made for people who are at an advanced stage of prostate cancer. It is appropriate for patients with asymptomatic metastatic prostate cancer which has become androgen independent. It has been shown to improve survival in patients whose cancer has become resistant to hormones. This treatment involves taking a patient's own white blood cells and using a drug that trains them to more actively attack cancer cells. Once these cells are removed from the patient, they are treated with the drug and placed back into the patient. After the treatment of these cells, they can kill cancer cells while leaving normal cells unharmed.
Another area of research is focal therapy for prostate cancer that attempts to mirror the evolution of breast cancer treatment, which often involves "lumpectomy" as part of the initial management of the disease. It involves treatment of only that part of the prostate that is affected by cancer and uses methods like cryotherapy (freezing), HIFU (heating), and brachytherapy (seed implantation) to treat the cancer. Focal therapy is still at its infancy and its role is unclear because of unresolved problems related to lack of a proper method for complete evaluation of cancer location within the prostate and the potential coexistence of many different cancerous areas within the same prostate.
There is also a great interest in inventing better methods to image prostate cancer to detect its location and spread in the body. Newer techniques like MRS (magnetic resonance spectroscopy), PET (positron emission tomography) and certain molecular imaging techniques hold promise in this regard.
Medically Reviewed by a Doctor on 12/9/2013
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