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Prostate Cancer Treatment Overview

The radiation oncologists at Emory Proton Therapy Center work with the multidisciplinary Prostate cancer team at Winship, which includes experts in urology, medical oncology, radiology, pathology, supportive oncology, dieticians, social workers, physical therapy, and cancer rehabilitation. Your prostate radiation oncologist will work closely with these other specialists to customize your proton prostate cancer treatment plan and coordinate your care. We can also partner and coordinate with a patient’s existing care team, whether they are across town or around the world.

Proton Therapy for Prostate Cancer

A prostate cancer diagnosis can be one of the biggest challenges you and your family will ever face. Our team is dedicated to helping you meet that challenge through supportive care using the most advanced prostate radiation treatments available. Proton therapy may be a more precise radiation option for treatment of your prostate cancer to help protect the function of important nearby organs like the rectum, bladder, and bowels, as well as reducing the risk of developing a future cancer. Our prostate cancer specialists will work with you to develop a personalized treatment plan which aims for fewer side effects and improved quality of life.

What We Treat

  • Prostate adenocarcinoma
  • Recurrent prostate cancer after surgery (post-prostatectomy adjuvant or salvage)
  • Prostate small cell carcinoma
  • Prostate sarcomas
  • Pelvic lymph node metastases
  • Re-irradiation

Not all prostate cancer is the same

When you are first diagnosed with prostate cancer, a natural response is to wonder “how severe is it?”  During consultation, our radiation oncologists evaluate several factors to perform a “risk stratification” of the prostate cancer. Risk stratification of prostate cancer relates to the prognosis (how bad is it; how likely is the cancer to spread or recur), guides recommendations on management, and identifies which treatment plans are most likely to cure the cancer.


Understanding a prostate cancer diagnosis can be overwhelming. There are many medical terms, different tests and procedures, and many treatment options to consider! If you meet with one of our expert prostate radiation oncologists in consultation, they will help you to cut through the clutter and focus on what’s relevant to your care. During consultation we also want to answer your questions, review your treatment options, address your concerns, and understand your desires. The best treatment plan is one which aligns with your preferences and goals. 

Understanding Risk Stratification

Several factors are used for risk stratification of prostate cancer, some of which are discussed below.

Prostate Specific Antigen (PSA) is a cornerstone of prostate cancer, used in screening, risk stratification, and disease surveillance. PSA is a protein made by prostate cells (including normal and cancerous prostate cells) and is detected in a blood sample.


PSA is not a perfect screening test but a low PSA level < 4 ng/mL has typically been considered “normal” with a low risk for prostate cancer. A higher PSA level can lead to further tests to look for prostate cancer. Guidelines have changed over time about whether and when men should have a PSA screening test for prostate cancer. According to the US Preventive Services Task Force, men aged 55 to 69 years old should participate in a shared decision with their medical provider about whether to undergo a PSA screening, weighing the potential benefits of early diagnosis against the potential harms of “false alarms” or eventual diagnosis and treatment of low risk prostate cancer which may never have needed treatment at all.


Once a prostate cancer diagnosis is confirmed, the PSA level is one important component used to understand the risks stratification of the prostate cancer. A PSA < 10 ng/mL is a favorable or low risk value, a PSA of 10 – 20 ng/mL is an intermediate value, and a PSA > 20 ng/mL is a high risk value. However, PSA needs to be evaluated in combination with other factors to understand the risk level of the cancer and best treatment options.


Finally, PSA is used to assess response to therapy. The term “biochemical control” refers to when the PSA values are consistent with no active cancer after treatment, while “biochemical failure” or “biochemical relapse” refers to occasions when the PSA rises above a threshold level after treatment and may indicate a recurrence of cancer.


PSA density refers to the total PSA divided by the size (volume) of the prostate. A higher PSA can simply be a by-product of having a larger prostate gland that is a common side effect of normal aging, also known as benign prostatic hyperplasia (BPH). So a higher PSA value in a small prostate gland is more worrisome than the same value in a bigger prostate gland. PSA velocity refers to how quickly the PSA is changing over time. A rapid rise in PSA is more concerning than a slow rise.

Gleason Score and Grade Group refers to the appearance of the cancer cells identified on a prostate biopsy. The Grade Group or Gleason Score is a key factor that guides recommendations about your treatment plan.

  • Grade Group 1 = Gleason 6 (or less). Cancer cells look very similar to healthy cells and are considered low-grade. This is the most favorable risk prostate cancer.
  • Grade Group 2 = Gleason 3+4=7. There are mainly low-grade cells but with some more aggressive cancer cells. Often called “favorable intermediate,” the prognosis for cure is still very good.
  • Grade Group 3 = Gleason 4+3=7. There are more aggressive cancer cells but still some low-grade cells too. Often called “unfavorable intermediate.”
  • Grade Group 4 = Gleason 8. The cancer cells are more aggressive.
  • Grade Group 5 = Gleason 9-10. These are the most aggressive prostate cancers, more likely to grow quickly and spread.

Staging (the TNM system) refers to an evaluation of the primary prostate Tumor (“T”), lymph Nodes (“N”) and whether the cancer has spread elsewhere in the body (Metastasis “M”). You may have a clinical T stage (written as cT) if you have not undergone surgery to remove the prostate or a pathologic T stage (pT) if you have undergone a surgery to remove the prostate. Clinical T stage is based on a digital rectal exam (DRE) to determine whether the cancer can be felt in the prostate. For many men the cancer cannot be felt (cT1c) while for others there may be a hard nodule felt on the prostate (cT2) or in more advanced disease, one may be able to feel the cancer extending outside the confines of the prostate gland (cT3).

Genomic or molecular testing refers to specialized testing which may be performed on a prostate biopsy or the tissue removed during prostatectomy. One common brand of genomic testing is the Decipher score, which looks at a panel of gene expression to help predict the risk that the prostate cancer may spread elsewhere in the body (distant metastasis). For some men, genomic testing may help guide decisions such as whether to pursue active surveillance, or whether and for how long to use androgen deprivation therapy (ADT). Your radiation oncologist can help you understand whether you may need or benefit from the information provided by genetic testing.

Prostate Cancer Risk Groups

The National Comprehensive Cancer Network (NCCN) provides one of the most commonly used risk stratification methods for prostate cancer. Using PSA, Grade Group, the T stage, and other factors, the NCCN has 6 risks groups:

  • Very low risk. Active surveillance is recommended for most patients. Active surveillance involves careful monitoring so that curative treatment may be offered if there are any future signs of the cancer becoming more aggressive. More than half of patients in active surveillance are able to safely avoid treatment for at least 10 years.
  • Low risk. Active surveillance is recommended for most patients.
  • Favorable intermediate risk. Active surveillance remains an option. Additional tests may help decide whether to pursue treatment rather than active surveillance. Both radiation (including proton therapy) and surgery may be treatment options.
  • Unfavorable intermediate risk. Treatment is generally recommended unless advanced age or other medical problems predicts a limited life expectancy. Both radiation (including proton therapy) and surgery may be treatment options. Androgen deprivation therapy is likely to be recommended.
  • High risk. Treatment is generally recommended. Both radiation (including proton therapy) and surgery may be treatment options. Androgen deprivation therapy is recommended.
  • Very high risk. Treatment is generally recommended. Both radiation (including proton therapy) and surgery may be treatment options. Androgen deprivation therapy is recommended.

Comparison of Proton and X-Ray Therapy

Proton Therapy

Proton therapy is an extremely precise form of radiation treatment that can often better focus the radiation to match the shape and depth of the target. After treating the target, protons stop, avoiding exit dose radiation through the body. By reducing or avoiding radiation to sensitive normal healthy tissues and organs, proton therapy may reduce some of the side effects that can occur as a result of radiation treatments.

X-Ray Therapy

X-ray based radiation typically requires more beams or angles to deliver the radiation to the target. Unlike proton therapy where the radiation stops at the target, x-rays continue to deliver radiation as they exit through the body. As a result, x-ray based treatments typically result in increased radiation to normal healthy tissues and organs.

Proton Therapy Spares Radiation to the Bladder and Rectum

Proton Therapy for Prostate Cancer Illustration
Proton Therapy
Xray Therapy for Prostate Cancer Illustration
X-Ray Therapy


In prostate radiation treatments, proton therapy can reduce or avoid radiation to surrounding healthy tissue and organs. Depending on the tumor location and type, proton therapy may achieve the following benefits:

  • Reduced risk of frequent urination or stinging or burning with urination during treatment, or of chronic urinary problems after treatment.
  • Reduced risk of nausea and diarrhea during treatment.
    Reduced risk of diarrhea and rectal soreness (proctitis) during treatment and of chronic rectal problems after treatments such as rectal bleeding or ulceration.
  • Reduced radiation to the bone marrow and circulating lymphocytes, which may help support the function of the immune system in taking on cancer.
  • Reduced risk of developing a future second tumor or cancer, which is most relevant in younger patients, those with a good prognosis and a long life expectancy, and those patients who may have genetic conditions putting them at higher risk for developing other cancers.

SpaceOAR® Hydrogel: Reducing Radiation Exposure

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The prostate and rectum are located very close to each other and are separated only by a small space. When undergoing proton therapy for prostate cancer, your doctor will determine if you are eligible for placement of a special hydrogel between the prostate and rectum (SpaceOAR®). The SpaceOAR hydrogel creates additional space between the prostate and the rectum to further reduce radiation exposure to the rectum, thereby minimizing unwanted side effects and potential injury to the rectum during treatment. More than 50,000 patients worldwide have been successfully treated with SpaceOAR Hydrogel.

The placement of the hydrogel is a minimally invasive procedure done within our center and the hydrogel remains inside the body throughout treatment. The material that the SpaceOAR Hydrogel is made from has been used in other implants such as surgical sealants used in the eye, brain and spine. The biodegradable material naturally dissolves after a few months and is cleared in your urine.

Schedule a Consultation

What to Expect With Proton Therapy

The first step in your care is a consultation. During consultation, we review your medical history, perform a physical exam, decide if any additional tests are needed, discuss all radiation options that may be appropriate for your treatment plan, make recommendations, and answer questions.

Patients with prostate cancer typically undergo a minor procedure to place three small markers in the prostate, called fiducial markers. These markers allow the treatment team to accurately align the treatment each day to the location of the prostate. Your doctor will also determine if you are also eligible for placement of a special hydrogel between the prostate and rectum (Space OAR®), which creates additional space between the prostate and the rectum to further reduce radiation exposure to the rectum and dissolves after a few months.

SpaceAOR Hydrogel Steps

After placement of the markers (and the hydrogel if applicable), most patients return another day for a “simulation” or planning session. During this visit our radiation therapists will help position you the way you will be treated each day. A CT scan will be done to create a picture of you in the treatment position to design your radiation plan. Some patients also undergo an MRI during this visit to help identify the target for treatment. It normally takes 10 days for the team to design the proton treatment plan and perform the quality assurance checks before treatment begins.

Depending on the stage and other factors, proton therapy for prostate cancer may be delivered over two weeks, six weeks, or eight weeks of therapy. Typically, radiation is given once daily during the weekdays, Monday through Friday. For those receiving five treatments or fewer, proton therapy may be delivered every other day. While some situations are treated with proton therapy alone, depending on the stage, Gleason score, PSA level and other factors, proton therapy may be combined with androgen deprivation or prostate brachytherapy. Proton therapy may also be used in patients who have had surgery or other cancer treatments as part of a comprehensive plan of care.

Like other types of radiation, proton therapy treatments are invisible and painless. Most prostate treatments average 20-30 minutes each day in the treatment room.

Patients are seen by the radiation oncology physician team weekly during treatment to monitor progress, answer questions, address concerns, and manage any side effects from treatment. Your radiation oncologist will discuss a plan to assess response to treatment and for long-term follow-up after therapy.

Studies on Proton Therapy in Prostate Cancer

Our team has identified these studies as examples of the clinical benefits of proton therapy in prostate cancer.

Patient Stories