Agent Orange Brief D10

AGENT ORANGE AND PROSTATE CANCER

Why are Vietnam veterans worried about prostate cancer?

In the United States there are about 28 million men 50 years of age or older. There are approximately 8.6 million male veterans aged 50-70. Autopsy studies have shown that nearly 30 percent of these men have prostate cancer. Thus, an estimated 2.5 million veterans may now have or will develop prostate cancer over a lifetime.

Some Vietnam veterans have already joined this age group (when prostate cancer is typically detected), while others are fast approaching the half century mark. Since prostate cancer is a slow-growing tumor, many in this population will die with the disease but from other causes. Prostate cancer is the most common non-skin cancer diagnosis in men, representing about 32 percent of all cancer cases. Prostate cancer is the second leading cause of death in men. It is estimate that more than 200,000 cases of prostate cancer (including about 10,000 veterans) will be diagnosed annually with an approximately 40,000 death. A problem with prostate cancer is that about 40 percent of the tumors have spread beyond the prostate before it is diagnosed.

How is prostate cancer detected?

There are currently three methods of screening: (1) digital rectal examination, (2) transrectal ultrasound, and (3) prostate specific antigen (a blood test to measure a protein found only in prostate tissue). Unfortunately, there are significant problems with each of these screening techniques. For each cancer detected, there are many false positives that may incorrectly diagnose a patient as having prostate cancer.

What treatments are available?

Since prostate cancer is a relatively slow-growing tumor compared to other cancers, the paradox in managing it is the need to intervene early to stop the disease and also being cautious about using the major treatment, radical prostatectomy. This is a serious procedure with significant complications. From 25 to 75 percent of patients will be impotent and 2 to 6 percent severely incontinent after the surgery.

In addition to surgery, current treatments for prostate cancer include radiation therapy, which has some unpleasant side effects, and male hormone (androgen) deprivation. Chemical or surgical deprivation or administration of estrogen is effective in relieving pain, reducing urinary obstruction, and improving general well-being. Endocrine therapy delays disease progression, but has not been shown to prolong survival.

A relatively new approach to treatment is known as "expectant management," which means following the patient and giving hormonal or surgical treatment as necessary. This approach is reasonable because the progression of the tumor for each patient is uncertain, the treatment effectiveness is uncertain, and many patients with prostate can die of cause other than prostate cancer.

What did the National Academy of Sciences (NAS) conclude about the relationship between exposure to herbicides and the development of prostate cancer in its 1993 report, entitled Veterans and Agent Orange - Health Effects of Herbicides Used in Vietnam?

The NAS reviewers observed that most of the agricultural studies they examined indicate "some elevated risk" of prostate cancer. Furthermore, one large well-done study in farmers showed an increased risk, and subanalyses in this study indicate that the increased risk specifically associated with herbicide exposure. The three major production worker studies reviewed by the NAS all show a small, but not statistically significant, elevation in risk. The NAS report noted that most of the associations seen in the studies reviewed are "relatively weak." The NAS added that Vietnam veterans have "not yet reached the age when this cancer tends to appear." In the report released in July 1993, the NAS concluded that there is "limited/suggestive evidence" of an association between exposure to herbicides used in Vietnam and prostate cancer.

What was VA's reaction to this NAS finding?

In its July 1993 report, the NAS placed three health outcomes in its category two (limited/suggestive evidence of an association): multiple myeloma, respiratory cancers, and prostate cancer. After careful review, Secretary Brown concluded that while the credible scientific evidence for an association is equal to or outweighs the evidence against an association between exposure to herbicides used in Vietnam and the development of multiple myeloma and of respiratory cancers, the evidence for an association between these herbicides and prostate cancers failed to reach that standard.

In January 1994, VA published a notice in the Federal Register that Secretary Brown has determined that a presumption of service connection based on exposure to herbicides used in Vietnam is not warranted for a long list of conditions identified in the NAS report. Prostate cancer was included in this list. (See 59 Fed. Reg. 341, January 4, 1994).

VA asked the NAS, in its follow-up report, to further consider the relationship between exposure to herbicides and the subsequent development of prostate cancer.

What did the 1996 NAS update conclude about prostate cancer?

Citing additional studies, the NAS report concluded that there is "limited/suggestive evidence" of an association between exposure to herbicides used in Vietnam and prostate cancer.

What was VA's response to the NAS 1996 finding regarding prostate cancer?

Secretary Brown found that the credible evidence for an association equals or outweighs the evidence against an association between exposure to herbicides used in Vietnam and prostate cancer. He concluded that prostate cancer should be added to the list of conditions recognized for presumption of service connection for Vietnam veterans based on exposure to herbicides. President Clinton announced this, along with other decisions, on May 28, 1996. The proposed rule to implement this decision was published for public comment in the Federal Register in August 1996. (See 61 Fed. Reg. 41368, August 8, 1996). The final rule was published in the Federal Register in November 1996. (See 61 Fed. Reg. 57587, November 7, 1996).

Where can a veteran get additional information about prostate cancer?

Information regarding prostate cancer and related matters can be obtained at VA medical center libraries, from the Registry Physicians at every VA medical center, or from the Environmental Agents Service (131), Department of Veterans Affairs, 810 Vermont Avenue, N.W., Washington, DC 20420.

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