NEW YORK -- Margot Morrell viewed her 2004 ovarian cancer diagnosis as a challenge.

"From the minute I was diagnosed, my focus was completely on how do I get over this as fast as possible so I can get back to work," said Morrell, an author and speaker.

More than one-third of the women in America and almost half the men will be diagnosed with cancer sometime in their lives, and for many, the diagnosis will come while they're working -- literally. Many patients hear the diagnosis for the first time when their doctor phones at work. Most continue working while they're treated.

According to a study of 1,433 cancer patients ages 25 to 62 published in the journal "Cancer," about 59 percent of men and 61 percent of women continued working during cancer treatment. Of those who stopped working, most returned to work the first year after treatment.

"Most people want to keep working," said Barbara Hoffman, a founding board member of the National Coalition for Cancer Survivorship. "Most people, if they are really not able to work will say, 'I can't come in this week, or this month, or these four months,' but they really want to reintegrate to work when they are able to."

One reason: Health insurance. Cathy J. Bradley, of the Massey Cancer Center at Virginia Commonwealth University in Richmond is studying cancer treatment and work. She found that 38 percent of prostate cancer patients said they kept working to maintain their health insurance. Married women with breast cancer whose health insurance is through their husband's employer are more likely to take time off than married women with breast cancer who are responsible for their own health insurance coverage.

Still, even the rich and famous seem eager to return to work.

ABC "World News Tonight" anchor Peter Jennings announced last April that he had been diagnosed with lung cancer and spoke hopefully about returning to work. (Jennings died in August.)

Apple Computer Inc. CEO Steve Jobs took only two months off after surgery for pancreatic cancer in 2004. Maria Friedman, the star of a Broadway musical, "The Woman in White," performed on opening night, 10 days after a lumpectomy for breast cancer. Her radiologist waited in the wings and the front-page New York Times headline read: "Musical really does go on as star is treated for cancer."

But the road is rocky for some cancer patients, who find treatment or complications make them sicker than they imagined.

Karen Pollitz was Deputy Assistant Secretary for health legislation at the Health and Human Services department during the Clinton administration in 1996 when she was diagnosed with breast cancer. Donna Shalala, then secretary of health and human services, called after the diagnosis and said: "You do what you need to do. You'll be OK."

Chemotherapy made Pollitz sick several days each cycle and a case of strep throat was so debilitating, she could barely turn her head. She ended up missing about two months of work.

"It was a nightmare," she said. "I wouldn't wish this on my worst enemy."

Researcher Bradley said, "To some extent, I feel like we do a disservice to make it seem like everyone can work while they get treatment. The reality is, not everyone can. And for some people, it's probably not good for them."

The study in "Cancer" found people's ability to return to work varied with the type of cancer they had. The highest rates of quitting were among those with blood, central nervous system and head and neck cancers, which tend to be the most debilitating and impairing cancers.

The lowest rates of quitting were among survivors of uterine, female breast, prostate and thyroid cancers.

Some people with cancer find that powering through treatment while working is a way to keep life normal. Meredith DeDona was diagnosed with osteosarcoma, a bone cancer, in 1992, when she was nine. Now 24, she has been fighting it ever since.

She interviewed for a college internship at Booz Allen Hamilton Inc. while she was in remission. Immediately afterward, she had a scan that showed something suspect. She called Booz Allen to see how the interview had gone and they told her they were going to make her an offer.

"I said, 'Well, I have something to tell you,"' DeDona said. They hired her and she's been balancing work as a community relations consultant and cancer treatment for most of the last four-and-a-half years.

"It's really important to me that I be able to keep working," she said. "It helps me keep a sense of normality in my life, which it would be easy to lose sight of. People will get the word that I'm working at home because I'm getting chemo and they'll say, 'You're getting chemo. Relax.' But what would I do? I would sit around, I would watch TV. I can do productive things."

DeDona, who describes herself as "a bit of a workaholic" said she doesn't take sick leave during some rounds of chemo because she works when she gets home and into the evening.

She said her boss, Barbara Haight, a senior community relations manager, has been extremely supportive. "What's really critical for a person in any similar situation is to have a supportive manager," she said. "If they're not behind you, it's not going to work."

Said Haight: "Because of sheer grit, she hasn't missed a beat all year."

Morrell, the co-author of "Shackleton's Way," a book about the leadership lessons of Antarctic explorer Ernest Shackleton, gives speeches about facing challenges.

She declined an out-of-town speaking engagement the night before she was scheduled for surgery and canceled a speech that would have required travel three weeks after surgery, but she did some consulting work during treatment. Her focus on completing treatment and resuming her normal work schedule was "a good goal to have and a really good perspective," she said.

When she gives speeches, "I talk about getting through challenges and when I mention that I'm a cancer survivor, that really resonates," she said. "It takes what I say from theory into fact."