Over the weekend, as the drama in Rome intensified, the ABC news staff knew something was amiss. Here was history-making news—and Peter Jennings was nowhere in sight. The absence was uncharacteristic for the deeply competitive veteran anchor. "Everyone had a sense that something had to be seriously wrong," says an ABC News producer. Then, on April 5, hours after alerting his colleagues, Jennings ended World News Tonight with a story about himself. Emotional and struggling against a hoarse throat, he said, "I have learned in the last couple of days that I have lung cancer. Yes, I was a smoker until 20 years ago, and I was weak and I smoked over 9/11. But whatever the reason, the news does slow you down a bit."

By then, friends and colleagues around the globe were bombarding Jennings, 66, with best wishes as he prepared to begin outpatient chemo treatments in New York City this week. "I'm heartbroken, but he's also a tough guy," said recently retired Tom Brokaw, who assumed the NBC anchor post the same night Jennings secured his solo anchor duties in 1983. CNN's Aaron Brown, a former ABC colleague, says that Jennings will lean most heavily on his two children, Elizabeth, 25, and Christopher, 22, and his fourth wife, ABC producer Kayce Freed, 47. "Peter relies a lot on Kayce's wisdom and strength," he says.

Jennings, who did a prime-time special about the tobacco industry in 2004, was eager to ease the worry of others. He joked in an e-mail to colleagues, "There will be good days and bad, which means that some days I may be cranky and some days really cranky!" He plans to keep working (Charles Gibson and Elizabeth Vargas will fill in on an as-needed basis) and seems determined to put his illness in perspective. "Almost 10 million Americans are already living with cancer," he told viewers. "I have a lot to learn from them."