Prostate
Definition of the Prostate
The prostate is a walnut-sized gland positioned in front of the rectum and underneath the urinary bladder. The prostate produces some of the fluid that protects and nourishes sperm cells in semen. Located behind the prostate gland are the seminal vesicles that make most of the fluid for semen. The urethra, a tube that carries urine and semen out of the body through the penis, runs through the prostate.
The prostate grows until a man reaches adulthood. The continued growth is attributed to testosterone, a male hormone. As long as male hormones are present, the prostate will remain about the same size throughout adulthood.
In older men, the inner part of the prostate around the urethra may continue to grow, a condition called benign prostatic hyperplasia (BPH). This can create problems during urination because it can press on the urethra (the tube that carries the urine); it is important to note that BPH is not cancer.
Types of Prostate Cancer
Nearly 100% of prostate cancers develop from the gland cells even though several types of cells are found in the prostate. Gland cells make the prostate fluid that is added to semen. Cancer that begins in the gland cells is called adenocarcinoma
Sarcoma is another type of cancer that can start in the prostate gland. However, this type of prostate cancer is rare.
Pre-cancerous Conditions of the Prostate
Prostate cancer can begin with a pre-cancerous condition called prostatic intraepithelial neoplasia (PIN). PIN can appear in the prostates of some men as early as their 20s, and almost half of all men develop PIN by the time they reach age 50.
In this condition, there are changes in how the prostate gland cells look under the microscope. The changes are classified as either low-grade, meaning the patterns of prostate cells appear almost normal; or high-grade, meaning they look more abnormal.
If a high-grade PIN is found during a prostate biopsy, a repeat biopsy can confirm whether the cell was cancerous.
Another finding that may be reported on a prostate biopsy is atypical small acinar proliferation (ASAP). In ASAP, the cells look like they might be cancerous when viewed under the microscope. If ASAP is found, the chance that cancer is present in the prostate is much greater and another biopsy would be advised.
Treatment of Prostate Cancer Using CyberKnife®
Prostate cancer is the most common form of cancer in men in the United States.
It can be a frightening diagnosis for men. Now, there is good news in the fight against this life-threatening disease.
At Saint Francis’ CyberKnife® Center, doctors are now using leading-edge technology to treat patients with prostate cancer. CyberKnife employs an advanced, lightweight linear accelerator (LINAC), a device mounted on a robotic arm. It is used to concentrate a high dose of radiation through multiple radiation beams on a designated tumor or lesion. Using image-guided cameras, the CyberKnife system locates the exact position of the tumor. There is no incision involved, and patients can resume normal activity immediately following treatment.
Patients typically undergo a five-day course of treatment with CyberKnife, compared to a seven- to eight-week regimen of treatments with traditional radiation therapy. The key, according to Jeffrey Steinberg, M.D., Chairman/Director of Surgery, is CyberKnife’s ability to deliver much higher doses of radiation than other treatment systems without radiating other nearby tissues.
“The placement of four gold seeds in the prostate ahead of treatment allows us to precisely focus this radiation on the cancerous tissue,” he explains. “We can deliver a much higher dose per day with the CyberKnife than we can with conventional radiation therapy, but the total dose is much lower than with conventional radiation therapy.”
Treatments for prostate cancer can last 45 minutes. To be eligible for CyberKnife treatment, a patient’s cancer must not have spread beyond the prostate.
“Studies so far have shown that CyberKnife is effective for the treatment of prostate cancer, and with fewer side effects and much more convenience for the patient,” says Richard Shumway, M.D., Co-Director of the Center and a radiation oncologist.
Initial data from Stanford Medical Center shows that severe urinary symptoms are less than 10 percent in the long term. “No one has published data on erectile function, but because of the more precise nature of radiation delivery and total lower dose with CyberKnife, it is reasonable to assume this is much less frequent than with conventional radiation therapy,” says Dr. Steinberg.