Radiation Therapy Treatment for Prostate Cancer

Radiation Therapy Options for Treating Prostate Cancer

After a diagnosis of prostate cancer has been established with a biopsy, the patient should discuss the treatment options with a radiation oncologist and a urologist. Radiation therapy treatment options to cure prostate cancer include:

• External beam radiotherapy - (IMRT/IGRT)
• Prostate brachytherapy.

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External Beam Radiation Therapy (3D, IGRT, IMRT, CBCT)

• Until recently, external beam radiation therapy using 3D Conformal radiation therapy was the gold standard approach. In this technique, many beams of radiation are focused to target tissues, reducing the areas of the bladder and rectum that recieve radiation.
• Intensity Modulated Radiation Therapy (IMRT) is the most commonly used radiation therapy for prostate cancer today. Unlike the 3D Conformal approach, IMRT conforms the radiation dose to the shape of the target in three dimensions, thus reducing the dose delivered to the nearby normal tissues, including the rectum and bladder. IMRT is associated with excellent outcomes and less toxicity.
• Image Guided Radiation Therapy (IGRT) refers to the use of modern imaging to improve the targeting and delivery of radiation treatment. With IGRT, a patient can be imaged in the treatment room while on the treatment table. This is a MAJOR advancement in that preious techniques required that patients were only imaged periodically. At North Shore Radiation Therapy, patients are imaged EVERYDAY prior to treatment to ensure accuracy. At our NEW site, IGRT is delivered on a brand new Varian Linear Accelerator, which is equipped with a state-of-the-art on-board imager (OBI). To accomplish this, small seeds are placed inside the prostate prior to treatment in a minor procedure done right in our office. These are used to locate the precise position of the prostate gland prior to EACH TREATMENT. The treatment couch is then adjusted to ensure that each and every treatment is accurate. IGRT improves therapuetic ratios by allowing our physicians at North Shore Radiation Therapy to safely and effectively escalate the dose to the prostate, while at the same time, reducing the dose to the surrounding tissues. An another feature of the Varian Linear Accelerator is the ability to generate volumetric images, known as cone-beam CT (CBCT) imaging. These CBCT images are obtained by rotating the OBI imager aroud the patient and reconstructing these images into a three dimesional image. These high quality images are done quickly and with a low dose to the patient. In contrast, other IGRT approaches (like Tomotherapy) use megavoltage x-rays. This results in inferior images and much higher doses to the patient.
• The ability to generate high-quality kV CBCT imges of the patient immediately prior to treatment is a new revolutionary treatment for prostate cancer available at North Shore Radiation Therapy.

Potential side effects, including fatigue, increased frequency or discomfort of urination, and loose stools, typically resolve within a few weeks after completing treatments. Impotence is also a potential side effect of any treatment for prostate cancer. However, many patients who receive radiation therapy for prostate cancer are able to maintain sexual function.

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Prostate Brachytherapy

Prostate brachytherapy, better known as a seed implant, is often done in the operating room.

There are two methods of delivering internal radiation for prostate cancer:

• Permanent seed implants.
• High-dose rate temporary seed implants.

These treatments are designed to deliver a very high dose of radiation to the tumor by inserting radioactive seeds directly into the prostate gland under ultrasound guidance while the patient is under anesthesia. Isotopes of iodine or palladium are most commonly used. The seeds are approximately four millimeters long and less than a millimeter in diameter. In certain situations, both prostate brachytherapy and external radiation may be recommended to combat the tumor.

The side effects from seed implants are similar to those experienced with external beam radiotherapy. Patients usually experience urinary frequency and discomfort in urination. These effects may be lessened with medication and usually dissipate over the course of three to six months.

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Proton Beam Therapy

In a few parts of the country, proton beam therapy is being used to treat prostate cancer.

Proton therapy is administered much the same way as external beam therapy, but it uses protons rather than x-rays to irradiate cancer cells.

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Hormone Therapy

Certain patients may benefit from hormone therapy in addition to radiation. In some patients, hormone therapy works with radiation therapy to improve cure rates.

Facts About Prostate Cancer

Prostate cancer is the most common malignancy in American men.

• In 2003, more than 220,000 men were diagnosed as having prostate cancer, making it the number one type of cancer in men.
• Nearly 29,000 men died from prostate cancer in 2003.
• More than 75 percent of prostate cancer is diagnosed in men over age 65.

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Risk Factors For Prostate Cancer

Incidence of prostate cancer increases with age.

• Median age at diagnosis in Caucasian males is 71.
• African-American men have the highest incidence of prostate cancer in the world.
• Heredity accounts for 5 to 10 percent of cases.

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Screening For Prostate Cancer

According to the American Cancer Society, men aged 50 or older should be offered a digital rectal exam (DRE) and a PSA blood test. However, it is a good idea to visit your doctor earlier to establish a baseline PSA level so you can monitor changes.

• Prostate specific antigen (PSA) is a valuable marker for prostate cancer although BPH or infection may also cause a rise in PSA.
• Normal range is 0-4, however, a PSA above 3 in men younger than 60 may be considered abnormal.
• African-American men and men with a family history of prostate cancer should be examined beginning at an earlier age.

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Diagnosing Prostate Cancer

Prostate cancer is most often diagnosed through a blood test measuring the amount of prostate specific antigens (PSA) in the body. However, signs and symptoms of prostate cancer can include:

• Changes in urinary flow: Frequency, urgency, hesitancy.
• Frequent nighttime urination.
• Painful urination.
• Blood in urine.

Other conditions that may cause these symptoms include an enlarged prostate (benign prostatic hypertrophy or BPH) or infection.

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