Warren Buffett has been diagnosed with stage 1 prostate cancer, according to a statement from Buffett and his company, Berkshire Hathaway, to shareholders.

In the letter, Buffett says he feels great, and that doctors don't believe his condition is life-threatening. He plans to begin a two-month course of radiation treatment mid-July.

At 81, a prostate cancer diagnosis is not entirely surprising. According to the Cleveland Clinic, 80 percent of men who reach their 80s will have some cancerous cells in the prostate.

The severity of prostate cancer is measured in stages. Stage 1 is the least advanced, and only found within the prostate, according to The National Cancer Institute. It is detected by biopsy, testing for a man's Gleason score and PSA (prostate-specific antigen) level. The higher the PSA level in the blood, the more likely there is cancer. "I discovered the cancer because my PSA level ... recently jumped beyond its normal elevation and a biopsy seemed warranted," Buffett said in the statement.

Buffett's diagnosis comes on the heels of actor Ryan O'Neal's announcement late last week that he has recently been diagnosed with stage 2 prostate cancer.

The actor, 70, who previously battled leukemia, said in a statement: "Although I was shocked and stunned by the news, I feel fortunate that it was detected early and according to my extraordinary team of doctors the prognosis is positive for a full recovery," People reported.

O'Neal and Buffett are among the growing ranks of men who have opted to speak out about their diagnoses, in the hopes of raising awareness for a disease that kills more than 28,000 men a year, according to the American Cancer Society. Here's a look at a few of those famous faces.

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  • Jerry Orbach

    The long-time "Law & Order" star announced his prostate cancer diagnosis in late 2004, at the age of 69. His manager said that he had been <a href="http://today.msnbc.msn.com/id/6765565/ns/today-entertainment/t/law-order-star-jerry-orbach-dies/#.T42htzLLzac" target="_hplink">receiving treatment since the spring</a>, and the series creator Dick Wolf told "People" that Orbach was <a href="http://www.people.com/people/article/0,,845383,00.html" target="_hplink">expected to make a full recovery</a>, but he <a href="http://gothamist.com/2004/12/29/farewell_jerry_orbach_has_died.php" target="_hplink">died just a few weeks later</a>.

  • Robert De Niro

    Little was disclosed about the actor's battle with prostate cancer, other than his 2003 diagnosis and the fact that <a href="http://articles.cnn.com/2003-10-20/entertainment/deniro.cancer_1_prostate-cancer-stan-rosenfield-full-recovery?_s=PM:SHOWBIZ" target="_hplink">doctors predicted a full recovery</a>, according to De Niro's spokesman. <a href="http://www.usatoday.com/news/health/2003-10-21-prostate-cancer-cover_x.htm" target="_hplink">His father died of cancer</a> in 1993 at the age of 71, according to <em>USA Today</em>, but De Niro was given a clean bill of health, even <a href="http://www.everydayhealth.com/prostate-cancer-pictures/famous-men-who-battled-prostate-cancer.aspx#/slide-2" target="_hplink">becoming a father for the sixth time in 2011</a>.

  • Nelson Mandela

    The former South African president was diagnosed with prostate cancer in July 2001, at the age of 83. Sixteen years earlier, he had surgery to remove some <a href="http://www.everydayhealth.com/prostate-cancer-pictures/famous-men-who-battled-prostate-cancer.aspx#/slide-11" target="_hplink">benign tumors on his prostate</a>, but a spokeswoman said the tumor was "microscopic" and would not require surgery this time. Instead, Mandela was treated with <a href="http://news.bbc.co.uk/2/hi/africa/1454103.stm" target="_hplink">seven weeks of radiation</a>.

  • Rudy Giuliani

    The former New York City mayor's father died of prostate cancer, so when he was diagnosed, he told <em>USA Today</em>, "I wished it would just go away." He said he didn't have any symptoms, but after a routine physical his doctor wanted him to see a urologist. After he was diagnosed, he opted for hormone therapy and radiation treatment and <a href="http://www.usatoday.com/news/health/spotlighthealth/2002-10-14-giuliani_x.htm" target="_hplink">urges all men over 50 to get screened</a>.

  • Joe Torre

    "In 1999 when I was first diagnosed <a href="http://www.usatoday.com/news/health/spotlighthealth/2003-06-10-torre_x.htm" target="_hplink">I had no symptoms</a>," the retired baseball manager, told <em>USA Today</em>. "When my prostate was removed, it was actually very normal looking. That's why they call it a silent killer." He was 58 at the time -- and his daughter only 3. "I wanted to be around for her," he told the <em>New York Times</em>, opting for <a href="http://www.nytimes.com/2011/05/29/sports/baseball/joe-torre-and-baseball-putting-the-focus-on-prostate-cancer.html" target="_hplink">aggressive surgery</a>. He has since spoken out in hopes of raising awareness.

  • Colin Powell

    The former Secretary of State had successful surgery in 2003 to <a href="http://articles.cnn.com/2003-12-15/us/powell.surgery_1_prostate-cancer-slow-growing-cancer-hormone-therapy?_s=PM:US" target="_hplink">remove his prostate</a> at age 66. Doctors didn't expect him to require much further care after <a href="http://www.webmd.com/prostate-cancer/news/20031215/colin-powell-undergoes-prostate-surgery" target="_hplink">two weeks of recuperation after the operation</a>.

  • John Kerry

    The senator underwent surgery in 2003 to remove his prostate, after being diagnosed with the disease that <a href="http://www.salon.com/2003/02/13/kerry_7/" target="_hplink">killed his father only three years earlier</a>. "Senator Kerry is a poster boy for early detection," his surgeon said in a statement. "We caught this very early and for that reason the prognosis couldn't be more optimistic." "It may sound strange to some of you, but I really feel very lucky as I stand here," Kerry said at a news conference, the <em>New York Times</em> reported. "And the reason I feel lucky is that <a href="http://www.nytimes.com/2003/02/12/us/kerry-to-undergo-surgery-for-prostate-cancer-today.html" target="_hplink">I'm going to be cured</a>."

  • Andrew Lloyd Weber

    In 2009, at age 61, the composer behind musicals including "The Phantom of the Opera" and "Evita" announced he was being treated for <a href="http://www.people.com/people/article/0,,20315334,00.html" target="_hplink">early stage prostate cancer</a>. In 2010, after getting a clean bill of health, Lloyd Weber, who was <a href="http://www.foxnews.com/story/0,2933,569475,00.html#ixzz1sK0TNL9f" target="_hplink">knighted in 1992</a> and named to Britain's House of Lords in 1997, spoke out in favor of prostate cancer <a href="http://www.webmd.boots.com/prostate-cancer/news/20100720/lloyd-webber-demands-prostate-cancer-screening" target="_hplink">screening for all men over 50</a>.

  • Arnold Palmer

    The golf legend was in the news recently after being hospitalized for <a href="http://www.huffingtonpost.com/2012/03/26/arnold-palmer-high-blood-pressure-hypertension-medication_n_1379959.html" target="_hplink">high blood pressure as a result of a new medication</a>, but he also made health headlines for beating prostate cancer in 1997. Deciding to have surgeons <a href="http://www.everydayhealth.com/prostate-cancer/0606/arnold-palmer-tees-up-for-prostate-cancer-awareness.aspx" target="_hplink">remove his prostate completely</a>, Palmer later told WebMD, "was probably the best thing I ever did."

  • Dennis Hopper

    The actor, best known for starring in "Easy Rider," lost his battle with prostate cancer in 2010 <a href="http://www.people.com/people/article/0,,20337801,00.html" target="_hplink">at the age of 74</a>. He <a href="http://latimesblogs.latimes.com/gossip/2010/01/dennis-hopper-divorce-prostate-cancer.html" target="_hplink">filed for divorce</a> in the middle of his illness, just as he began a round of chemotherapy, saying in a statement "I... only want to spend these difficult days surrounded by my children and close friends." He was honored with a <a href="http://articles.latimes.com/2010/may/30/local/la-me-hopper-20100530" target="_hplink">star on the Hollywood Walk of Fame</a> in March, just months before passing away.

  • Bob Dole

    The now-retired Kansas senator was diagnosed and treated for prostate cancer in 1991. He credits <a href="http://articles.chicagotribune.com/1992-05-18/news/9202140781_1_prostate-cancer-early-detection-dole" target="_hplink">early detection</a> as key to beating the disease, and afterward gave interviews, appeared in TV ads and spoke to Congress to promote communication between men and their doctors about <a href="http://www.cbsnews.com/2100-204_162-9004.html" target="_hplink">prostate-related problems</a>.

  • Harry Belafonte

    In the mid-90s, the singer was diagnosed with prostate cancer after a routine checkup. Surgeons successfully <a href="http://www.people.com/people/article/0,,20142089,00.html" target="_hplink">removed his prostate</a> and he began to speak out in hopes of raising public awareness of a disease he called "an epidemic." He focused in particular on how men in the past seemed <a href="http://articles.latimes.com/1997-04-21/news/ls-50829_1_prostate-cancer" target="_hplink">too "macho" to discuss prostate cancer</a>. He told the <em>LA Times</em>: <blockquote>The prostate is something that attacks that central part of the male body that men are very preoccupied with. Somehow, any disorder there means your life is over, you can't be a man anymore, you are now something less.</blockquote>

  • Francois Mitterand

    The former president of France was diagnosed with prostate cancer soon after he was elected in 1981, but didn't announce his illness to the public for more than 10 years, after he had <a href="http://www.nytimes.com/1996/01/10/news/10iht-mitt.t_0.html" target="_hplink">surgery in 1992</a>. Only <a href="http://www.time.com/time/magazine/article/0,9171,984025,00.html" target="_hplink">one in 10 men with his diagnosis survives</a> longer than a decade, according to "Time," but he did, thanks to a treatment regimen of hormones and other therapies, according to the <em>New York Times</em>, until his <a href="http://news.bbc.co.uk/onthisday/hi/dates/stories/january/8/newsid_4489000/4489322.stm" target="_hplink">death in 1996</a>, at 79, from the disease.

  • Eddie Montgomery

    Country musician and member of Montgomery Gentry band said in a statement that he had been <a href="http://www.people.com/people/article/0,,20443662,00.html" target="_hplink">diagnosed with prostate cancer in 2010</a>. "I will be undergoing surgery to remove the cancerous tumor in December," he said. "I will be back in January ready to rock for all the fans!" "People" reported.

  • Don Imus

    The controversial radio host announced his diagnosis of <a href="http://www.huffingtonpost.com/2009/03/16/don-imus-i-have-prostate_n_175203.html" target="_hplink">Stage 2 prostate cancer</a> on his morning show in 2009. He <a href="http://www.people.com/people/article/0,,20265826,00.html" target="_hplink">said the prognosis was positive</a>, and that he had great faith in his doctors, People.com reported. "I'll be fine. If I'm not fine, then I won't be fine. And it's not a big deal," he said.

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