Cancer experts worry that environmental pollution might be responsible for the high increases in testicular cancer over the last 30 years. (Marco Doelling/ABCNEWS.com)

By Claudine Chamberlain
ABCNEWS.com
Jan. 25 — A Canadian study released today confirms a trend that cancer experts are noticing around the world: Rates of testicular cancer have increased sharply in the past three decades, especially among young men who probably thought they had no reason to worry about the dreaded "C" word.

Doctors who treat this still-rare disease don’t know for sure why it’s on the rise, but by a process of elimination, they suspect the culprit could be environmental pollution.

       Writing in the Canadian Medical Association Journal, researchers from Cancer Care Ontario and the Centers for Disease Control and Prevention say the cancer rate for the province of Ontario is up nearly 60 percent from 1964, rising about 2.37 percent a year for 15- to 29-year-olds and 1.46 percent a year for 30- to 44-year-olds.
     But it’s not an Ontario-only problem. Similarly dramatic increases have also hit the United States and Europe.

Tracking Down the Cause  The American Cancer Society estimates that about 7,600 new cases of testicular cancer are diagnosed each year in the United States. For Canada, it’s 760 new cases a year. An estimated 400 U.S. men and 35 Canadian men died of the disease last year.
       Symptoms include a lump in either testicle, any enlargement of a testicle, a feeling of heaviness in the scrotum, pain or discomfort in a testicle or in the scrotum and, in some cases, enlargement or tenderness in the breast area.
     "It’s a devastating problem for these guys," especially since they tend to be so young, says Dr. Michael Jewett, head of urology at Toronto Hospital. "They’re immortal when they’re 20 and they haven’t often had experience with major illness."
     Dr. Phillip Kantoff, a genitourinary cancer expert at the Dana Farber Cancer Institute in Boston, says huge increases in rates of a disease are usually due to better detection or reporting. But that’s not the case with testicular cancer.
       "You go through the checklist of what might be responsible for the increase, and my conclusion at the end of looking at it all is that [better detection and reporting are] not the case," he says. "Then environmental exposures become the obvious explanation."
     The question then becomes, what in the environment might be causing this?
     The main risk factor for testicular cancer is an uncommon abnormality in which a boy’s testicles had not descended from the abdomen into the scrotum at birth. That means that in most cases, the risk for cancer develops before birth.

Hormonal Havoc
Experts suspect environmental pollution contributes to that abnormality, as well as other reproductive system problems. In recent years, several other international studies have shown declining sperm counts, a reduction in testicle size and other male genital abnormalities.

       Taken as a group, these problems seem to show a common link, says Dr. Laurence Klotz of the University of Toronto.

     Certain environmental toxins are thought to wreak havoc with the body’s hormones because they mimic the effect of natural human hormones. Some believe such "endocrine disrupter" chemicals, particularly pesticides, are responsible for other problems in the reproductive organs, such as early puberty and breast cancer.

      So, Klotz says, it’s a "reasonable hypothesis" that exposure to toxins may harm the early fetal development of sex organs, leading to problems that later put a man at risk for testicle cancer.

    "I think this bears watching," he told Canadian TV News. "It warrants significant research efforts to nail down which molecules are responsible if it’s endocrine disruptions in the environment doing it."
 

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