Romney, who is 70, had surgery over the summer, according to a statement provided to ABC News. His treatment was successful, and "his prognosis is good," the statement said.
What does it mean to have a good prognosis for prostate cancer? [5 Things You Should Know About Prostate Cancer]
Though prostate cancer is the second leading cause of death related to cancer in men in the U.S., most men who are diagnosed with this cancer do not die from it, according to the American Cancer Society (ACS). "In fact, more than 2.9 million men in the United States who have been diagnosed with prostate cancer at some point are still alive today," the ACS says.
The ACS estimates that in in the United States in 2018, there will be about 164,700 new cases of prostate cancer and about 29,400 deaths from the disease.
In general, prostate cancer has high survival rates. The five-year relative survival rate — a measure of how likely a man with the cancer is to live for five years compared with a man without cancer — is 99 percent for men who received treatment for prostate cancer, according to the ACS.
Similarly, the 10-year relative survival rate is 98 percent, and the 15-year relative survival rate is 96 percent for men who received treatment.
Survival rates depend on how advanced the cancer was when it was first detected. In nearly 80 percent of all cases, prostate cancer is detected at the "localized" stage, according to the National Cancer Institute (NCI). (Localized means that the cancer is found only in the part of the body where it formed; in other words, it hasn't spread.)
The five-year survival rate for prostate cancer detected at the localized stage is 100 percent, according to the NCI. For cancer detected at the regional stage (meaning that the cancer has spread to nearby areas of the body), the five-year survival rate is also 100 percent, the NCI says.
The five-year survival rate drops significantly for prostate cancer not detected until it had spread to distant parts of the body, including distant lymph nodes, bones or other organs. About 5 percent of prostate cancers are first detected in this stage, and the five-year survival rate is about 30 percent, according to the NCI.
Originally published on Live Science.