It's been less than three months since Warren Buffett stunned Berkshire Hathaway (NYSE: BRK-A) (NYSE: BRK-B) with news that he has stage 1 prostate cancer.

He was quick to play down the diagnosis, and rightfully so. It was detected early, and Buffett claims that it's not life-threatening. Cancer is ugly, and most of us have lost loved ones to the disease, but medical advances in both detecting and treating it make this a winnable war in many cases.

Unfortunately, it doesn't always play out that way.

Tellabs (Nasdaq: TLAB) CEO Rob Pullen passed away yesterday. The telecommunications equipment company's helmsman lost his battle with colon cancer.

A few hours after Tellabs' announcement, security software specialist Sourcefire (Nasdaq: FIRE) announced that CEO John Burris would be taking a medical leave of absence. He will be receiving treatment for colon cancer.

Two tech CEOs in colon-cancer-related announcements in the same day is an unfortunate coincidence, but it's also likely to draw attention to Buffett's situation. Yes, it's prostate cancer. Yes, it was caught early. However, investors can't be reminded enough about Buffett's mortality.

He turns 82 next month. No one lasts forever, even someone as zestful and with as cheery a disposition as Buffett. It also doesn't help that Berkshire Hathaway's investments in recent years haven't been as successful as Buffett's calls earlier in his career.

Buffett claims to have already chosen a successor -- and two backups -- though the actual names haven't been made public. As more cancer stories creep up, you can be sure that attention will turn back to Buffett. In the end, though, cancer may not be as life-threatening as time itself for Buffett. We all need to go sometime, and the greatest investor of our generation knows that.