Buffett, 81, said his "condition is not remotely life-threatening or even debilitating in any meaningful way."

NEW YORK (CNNMoney) -- Iconic investor Warren Buffett announced Tuesday that he has been diagnosed with stage I prostate cancer in a letter to shareholders of his firm Berkshire Hathaway.

Buffett, 81, said his "condition is not remotely life-threatening or even debilitating in any meaningful way," and that additional tests didn't reveal incidence of cancer anywhere else in his body.

"I feel great -- as if I were in my normal excellent health -- and my energy level is 100%," wrote Buffett. "I will let shareholders know immediately should my health situation change. Eventually, of course, it will; but I believe that day is a long way off."

Over 70% of men who are diagnosed with prostate cancer don't die from the disease, according to Dr. Otis Brawley, a prostate cancer expert and the chief medical officer for the American Cancer Society.

"The 5-year survival rate for stage 1 prostate cancer is over 99%," he said.

Given that Buffett's cancer is in stage 1, the lowest stage, it has not spread to outside the prostate and has not yet spread to lymph nodes.

Buffett said he will undergo daily radiation for two months beginning in mid-July, a decision made with his doctors.

While the treatment will restrict him from traveling during the period, Buffett said his daily routine will not otherwise change.