Prostate cancer is a significant disease in the U.S. In 2014 alone, the American Cancer Society estimates, 233,000 men will be diagnosed and 29,480 will die of it.

This week, two important studies showing how prostate cancer is treated in the U.S. were published in the journal JAMA Internal Medicine.

The findings should cause those of us who treat prostate cancer and the organizations that advocate for prostate cancer awareness to take notice. These studies found that a large number of American men with prostate cancer get unnecessary and aggressive treatment. In some cases, these treatments are known to be worthless and even harmful.

One study more than 20 years long and involving more than 60,000 men diagnosed with cancer confined to the prostate found that initial treatment with anti-androgen hormonal therapies is common. This study also confirmed previous research showing that this treatment in this population does not prolong survival.

This is a therapy that is appropriate for a small, well-defined group of men with prostate cancer. It is an unnecessary and harmful treatment for the majority of Americans prescribed it. The hormones used cause hot flashes, muscle weakness, osteoporosis and impotence in all who get it. These drugs also raise a man’s risk of diabetes, cardiovascular disease and death from cardiovascular disease.

A second study showed that there is significant variation in how physicians treat good-prognosis (low-grade, less aggressive) cancer confined to the prostate. A substantial number get unnecessarily aggressive surgical or radiation therapies. These unnecessary therapies are also associated with significant harms. They can cause urinary and bowel incontinence, sexual impotence and, in some cases, death.

A number of studies in the U.S. and Europe have shown that there is a type of prostate cancer that is localized to the prostate and of good prognosis, meaning it rarely progresses or causes harm if left alone.

All of the organizations that set treatment guidelines based on the scientific evidence recommend that men diagnosed with this type of cancer be carefully observed. These cancers can almost always be effectively treated if found to be progressing. With careful observation, the majority of men will never need treatment and can be spared the burdens of unnecessary therapy.