Established radiotherapeutic treatments for early stage (localized) prostate cancer

Patients who elect to have some form of radiation therapy which is intended to cure their prostate cancer should have cancer that is confined to the prostate and/or the immediately surrounding tissues (i.e., clinical stages T1, T2, and T3).  As with patients who elect surgery, evident signs and symptoms of metastatic disease should be clearly ruled out prior to therapy.

Until the early to mid-1990s, radiation therapy for the treatment of prostate cancer was only widely available in one form: so-called “wide-field,” external beam radiation. “Wide-field” radiation was difficult to focus with precision on the prostate alone. This meant that the total amount of radiation that could be given was limited, and the risk of side effects to the tissues surrounding the prostate (e.g., the rectum, the bladder, and other tissues) was not negligible.

Over the past 15 years the situation has changed almost beyond recognition. So here is a list of the types of radiation that are available today for the treatment of early stage, localized prostate cancer with curative intent:

  • Conformal beam radiation therapy (CRT), which is any form of radiotherapy designed to radiate the precise volume of the prostate (or the prostate and selected nearby tissues as necessary)
  • Intensity-modulated radiation therapy (IMRT), which is a form of radiation therapy in which the intensity of the radiation delivered to a specific area of the prostate can be carefully controlled in  order to maximize the amount of radiation delivered to selected areas of the prostate and to minimize the risk of excess radiation to non-targeted tissues
  • Photon beam radiation therapy (“standard” external beam radiation therapy or EBRT), in which photons are the particles used to radiate the target tissues
  • Proton beam radiation therapy (PBRT) , which uses protons (as opposed to photons) as the form of ionizing radiation
  • So-called CyberKnife radiotherapy, using a technique known as stereotactic body radiation therapy, which permits higher doses of radiation to be targeted to the prostate and therefore allows the patient to be treated with fewer visits to the radiotherapy center
  • So-called RapidArc radiotherapy, using a modified form of IMRT, which also allows higher doses of radiation to be targeted to the prostate and therefore allows the patient to be treated with fewer visits to the radiotherapy center
  • Classical brachytherapy, in which radioactive pellets or seeds are permanently implanted into the prostate according to a predesigned three-dimensional pattern, and the pellets radiate the prostate over time
  • So-called high dose radiation (HDR) brachytherapy, in which radioactive pellets or seeds are temporarily implanted into the prostate according to a predesigned three-dimensional pattern using ultrafine needles, and the pellets radiate the prostate for a brief period of timke and are then withdrawn
  • Some combination of brachytherapy and external beam radiation therapy, which is may be appropriate for use in carefully selected patients.

In other sections we will address relevant details of each of these forms of radiation treatment.

Like surgery, all forms of radiation therapy are associated with complications, including acute cystitis (inflammation of the bladder and/or the urethra), proctitis (inflammation of the rectum), and enteritis (inflammation of the intestine, commonly associated with diarrhea). In addition, most series of radiotherapy patients have been associated with some subsequent urinary and sexual dysfunction.

Also as with surgery, patients are advised that better outcomes tend to be associated with radiotherapy centers carrying out treatment on large numbers of patients with prostate cancer.

There are two things that are very important for you to understand about radiotherapy as a treatment for localized prostate cancer and that are very different from surgery:

  • After surgery, a pathologist can look at the prostate removed by the surgeon and tell precisely what the pathological stage and grade of your disease really was. This is not possible after radiotherapy because the remaining prostate tissues (hopefully all dead) are still in your body. This means that if you have radiation therapy for localized prostate cancer, you will never know what the pathological stage of your cancer was post-treatment.
  • Also, after surgery, if the operation is successful and all of the prostate tissue is removed, your PSA will drop rapidly to < 0.1 ng/ml (or < 0.03 ng/ml if your urologist has requested an ultrasensitive PSA test). In the case of radiotherapy, however, the PSA will drop much more slowly to what is known as a “nadir” value (the lowest value that it reaches). The nadir is rarely as low as <0.1 ng/ml. Furthermore, the PSA may then rise again slightly after it reaches a nadir level before it stabilizes. (This is often referred to as a PSA “bounce”.) A man who is effectively treated with curative radiation therapy (of any type) may therefore end up with a PSA level somewhere between 0.2 and 1.0 ng/ml, but it should not be surprising if the PSA rises again over time to as much as 3.0 ng/ml.

External beam radiation therapy and proton beam radiation therapy have historically required daily visits to the radiation oncologist over a period of several (usually about 8) weeks. Patients receive treatment every day Monday through Friday, with a rest period over the weekend. Some men can find this very difficult to manage. By comparison, permanent and temporary forms of brachytherapy can be carried out on an outpatient basis in a single day. More recently the CyberKnife and RapidArc techniques have allowed for external beam radiotherapy to be carried out with just 5 visits to the radiotherapy center, significantly easing the burden on the patient to be available on a daily basis for an extended period.

If you want to consider any form of external beam radiotherapy as a treatment for your prostate cancer, we suggest that you read “Nine tips to picking a radiation oncologist to treat your prostate cancer,” by Matthew Katz, MD. If you are interested in considering brachytherapy as a form of treatment, we recommend that you read “How to select your brachytherapist,” by Michael F. Sarosdy, MD.

Content on this page last reviewed and updated May 15, 2009.
%d bloggers like this: