Radiation Treatment

After surgery, radiation is the most frequent treatment of prostate cancer in the United States. Its popularity increased after Andy Grove, chairman of Intel, published a 1996 Fortune magazine cover story account of why he had selected radiation treatment for his prostate cancer. An analysis of Medicare data found that radioactive seed therapy (brachytherapy) ''is replacing radical prostatectomy as the treatment of choice for early-stage prostate cancer.''1 Radiation is, of course, used to treat many forms of cancer. It works by disrupting the deoxyribonucleic acid (DNA) of cancer cells, which grow more rapidly than do normal cells; both types of cells are damaged, but cancer cells are damaged more severely.

Radiation has been used to treat prostate cancer since the early years of the last century. One of the originators of the idea was Alexander Graham Bell. In 1903, while president of the National Geographic Society, Bell wrote to a physician who was treating cancer: ''There is no reason why a tiny fragment of radium sealed in a fine glass tube should not be inserted into the very heart of the cancer, thus acting directly upon the diseased material.'' Bell's suggestion was implemented, and by 1917 reports began to be published on the efficacy of radium, inserted directly into the tumor, for treating prostate cancer.2 The use of external radiation to treat prostate cancer, called beam therapy, did not become widespread until the 1960s.

Both forms of radiation treatment—placing the radioactive substance into the cancer, and beaming it into the cancer from outside the body—are widely used. The former is now widely referred to as seed therapy. Officially, it is called interstitial radiotherapy or brachy-therapy, ''brachy'' being the Greek word for short and implying that the radiation is placed a short distance from the cancer. The seeds may be implanted permanently or just for several hours; the latter is known as high dose rate (HDR) brachytherapy. Radioactive forms of iodine, palladium, and iridium are presently used to generate the radiation.

Radiation can be beamed into the body from an external source in a variety of ways. The newer methods utilize computers and hightech equipment to focus the radioactivity sharply on the cancerous tissue, thereby causing less damage to the surrounding tissues and fewer complications. Beam therapy is officially referred to as external beam radiation therapy (EBRT), and the newer variations are called three-dimensional conformal radiation therapy (3DCRT) and intensity-modulated radiotherapy (IMRT). Proton and neutron beam radiation are in experimental stages. The technology of both seed and beam radiation treatment is continuously evolving; it is likely to improve further, especially in the ability to focus the radiation specifically on the cancerous tissue.

Ways Radiation Is Used to Treat Prostate Cancer

A. By placing the radioactive substance directly into the cancer. This is called seed therapy, brachytherapy, or interstitial radiotherapy.

1. Permanent: Seeds are inserted and left in permanently.

2. Temporary: Seeds are implanted for several hours, then removed. This is called HDR (high dose rate) brachytherapy and is sometimes referred to as the Andy Grove method, since it was popularized by the Intel chairman.

B. By beaming the radiation into the cancer from outside.

This is called external beam radiation therapy, or EBRT.

1. Three-dimensional conformal radiation therapy (3DCRT): special computers produce a precise focus of the beam.

2. Intensity-modulated radiotherapy (IMRT): a high-tech version of 3DCRT in which radiation comes from multiple directions.

3. Conformal proton beam radiation therapy: as above, but using protons rather than X-rays.

WHO ARE GOOD CANDIDATES?

Radiation treatment, like surgical treatment, works best on men with less severe forms of prostate cancer. Ideal candidates are thus men whose tumor is not palpable (stage T1c), or palpable but occupying less than half of one lobe (stage T2a); whose PSA is less than 10; and whose Gleason score is 6 or less. For Gleason scores of 7 or more, seed therapy is not recommended unless it is used together with beam therapy. One study showed that the best candidates for beam therapy are those with the lowest percentages of cancer-positive cores (one third or less) on biopsy; this finding is similar to the recommendation for good candidates for surgical treatment.3

A Man Who Chose Beam Therapy

If I have surgery, I'll be inactive for a long time. I'm in good shape for seventy-eight and want to stay that way a while longer. I don't know what side effects I'll have with radiation but I'm optimistic, I feel I'll be able to continue my power walks, travels and work. . . . I need to be in Boulder for an Antarctic workshop May 7 to 9.

—Charles Neider, Adam's Burden

Men who do not wish to have surgery or who cannot have surgery for medical reasons are also candidates for radiation therapy. Some men simply do not wish to subject themselves to a major surgical procedure with its attendant risks and extended recovery period. Others have heart, lung, kidney, or other medical conditions that increase the risk of major surgery. Seed therapy requires minor surgery and thus can be carried out on many of these men; beam therapy requires no surgery at all and is often the first choice of such men.

It can also be argued that radiation therapy is a wise choice for older men, especially those with a life expectancy of less than fifteen years. As will be discussed below, the long-term survival of men treated with radiation appears to be as high as that of those treated surgically for at least the first ten years following diagnosis of their cancer; if surgical treatment has an advantage in regard to life expectancy, it probably becomes manifest only after that period. Therefore, if a man is not likely to live more than ten years, it is logical to select a treatment without the burden and complications of prostate surgery. In practice, older men are more likely to choose radiation over surgical treatment; in one study of men in their 70s, radiation was chosen seven times more frequently than surgery.4

Finally, beam radiation therapy is increasingly being used for men who have undergone surgical removal of their prostate cancer but in whom, following surgery, it is discovered that not all the

A Man Who Chose a Combination of Seed Therapy and Beam Therapy

Whatever therapy I chose, I would be willing to accept an increased risk of dying, if I could preserve my sexuality. I also vowed to do whatever I could to avoid becoming a urological cripple. That determination would become my compass, as I worked to set a course in—what was for me—the uncharted wilderness of cancer.

—Michael Dorso, Seeds of Hope cancer was removed (there is a ''positive margin,'' or the cancer has spread through the prostate capsule). A 2005 European study demonstrated definitively that beam therapy following such surgery significantly improved the outcome.5

Finally, men may select radiation treatment because they believe that it has fewer side effects, especially incontinence and impotence, than surgical treatment.

Some men are not viable candidates for radiation treatment, especially those with large prostates (over 50 to 60 grams). A normal prostate in a young man weighs approximately 20 grams, then increases gradually as he ages. Large prostates require more seeds, a fact that increases the treatment's side effects. Large prostates are also difficult to irradiate adequately by beam therapy without injuring the surrounding tissues and without leaving untreated areas of the prostate (commonly referred to as ''cold spots''). In some cases, the size of large prostates can be reduced by first giving hormone treatment. Many urologists believe that men with diseases of the urinary tract or diseases of the colon, such as ulcerative colitis, are not appropriate candidates for radiation treatment because radiation may exacerbate those diseases. Finally, seed therapy is generally not used for men who have previously had part of their prostate removed surgically to relieve symptoms of BPH; scar tissue complicates the plac ing of the seeds. For recurrent cancers, seed therapy by itself is not used, although beam therapy is used, often in conjunction with hormone therapy (see Chapter 11).

In the past, seed therapy and beam therapy have each been used by themselves. Today, increasingly, they are being used together or in conjunction with other treatments. This is true not only for advanced cancers but also for early- and intermediate-stage cancers, some of which are currently being treated with both seed and beam therapy or with beam and hormone therapy. Such use of combined treatments remains controversial; some radiation advocates argue that seed or beam radiation therapy by itself is sufficient, while others argue that combined therapy produces better outcomes. The data to resolve this controversy do not yet exist.

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