What to know about prostate cancer after Mitt Romney's announcement

— -- As Mitt Romney is said to be considering a run for the Senate, many people are asking how his newly announced battle with prostate cancer could affect his health.

"Mitt Romney was treated over the summer for prostate cancer," an aide for Romney said in a statement obtained by ABC News. "He was treated surgically by Dr. Thomas Ahlering at U.C. Irvine Hospital in California. His prognosis is good; he was successfully treated."

But what does successful treatment mean and what is the prognosis for prostate cancer?

Prostate cancer is the second most common cancer in men, according to the American Cancer Society. It is also one of the most successfully treated cancers, with very good prognosis for many patients. There are many different options for screening and treating prostate cancer.

Here's more information about the disease.

What is the prostate?

The prostate, a gland in men that sits right below the bladder, is often said to be the size of a walnut. The size normally increases with age, but when a man has prostate cancer, the cells of the prostate begin to increase rapidly.

Early stages of prostate cancer usually have minimal outward symptoms, but it can show up as trouble urinating, blood in the semen, decreased urine stream or erectile dysfunction.

All men, but particularly older men, are susceptible to the disease. According to the American Cancer Association the average age at diagnosis is 66, and most cases -- about 60 percent -- occur in men 65 and older. It is rare in men younger than 40.

A family history of prostate cancer increases risk. African American men also tend to have a higher risk.

In 2017, there were 161,360 new cases of prostate cancer diagnosed and 28,343 men died of the disease, according to the American Cancer Society.

Screening for prostate cancer

Debate continues about who should and should not be screened for prostate cancer.

The PSA test looks for a protein in the blood that is often elevated when prostate cancer is present. Most experts, at this point, do not recommend everyone get this test because it can lead to unclear results – which, in turn, can lead to more biopsies and ultrasounds that turn out to be unnecessary, even harmful.

Most experts recommend having a “risks and benefits” discussion with doctors to determine if prostate cancer screening is appropriate, since the risks –- including impotence or incontinence -- can be serious.

Treatments for prostate cancer

There are many different treatment options for prostate cancer. They include a “wait and see” approach if the cancer is non-aggressive, chemotherapy, radiation, medications that disrupt hormones to slow the growth of cancer or even surgery to take out the entire prostate.

What treatment option may be best depends on factors like a person’s overall health, whether the cancer is aggressive and if the cancer has spread to other parts of the body.

It’s not all doom and gloom. While it can depend on the stage of the cancer when it is diagnosed, the overall five-year survival rate for prostate cancer is 99 percent and the 15-year survival rate is 96 percent, according to the American Cancer Society.