Nate promised to get a colonoscopy.

As many as 90 million Americans could be ignoring their medical problems because they're scared of going to the doctor for simple screening tests. Dr. Oz says these people are letting their emotions put their lives at risk. "There are so many things we can do today that can prevent all the hardships down the road," he says. "People don't realize how important it can be for them."

One of those people who was hesitant to go is Nate, a Chicago firefighter. In October 2007, when Dr. Oz and 300 men took over The Oprah Show , Nate told Dr. Oz he was scared about colon cancer because his brother died at 35the same age Nate is now. Dr. Oz made Nate promise to get a colonoscopy, a colon cancer test.
Dr. Oz explains how colon cancer develops.

In New York preparing for his colonoscopy by drinking a gallon of a mixture designed to cleanse his system, Nate got a pep talk from Dr. Oz. "The hardest part of the whole process is that stuff. By far. You talk to a hundred people who have colonoscopies, 99 will say that fluid was the hardest part."

The next day Nate was all cleaned out and ready for his colonoscopy with Dr. Jon LaPook of New York-Presbyterian Columbia Hospital. "I know you've got a lot of anxiety going into this. I would, too," Dr. Oz tells Nate. "But you ought to see this as any kind of athletic event in your life, any kind of major process that you had to get ready for emotionally and physically. It's the same kind of thing."

Dr. Oz says colon cancer starts as a benign polyp, or growth in the lining of the colon. While not all polyps lead to cancer, those that are precancerous usually develop into cancer in 5 to 15 years. From there they can spread to the liver and beyond.
Dr. LaPook removed six polyps.

During Nate's colonoscopy, Dr. LaPook uses a tool called a colonoscope to search for any polyps and remove them immediately. While not all polyps are cancerous, if a doctor finds a polyp during a colonoscopy, he or she will always remove it. "I'd rather he not have a polyp," Dr. LaPook says. "But if he has a polyp, how great that he came in here and we're able to catch it now."

Dr. Oz says that this immediate removal of polypswhether they're precancerous or completely benignshould make colon cancer incredibly survivable. "We can save the most lives because you truly cure people just by finding it."

As he's searching in Nate's colon for polyps, Dr. LaPook says there doesn't seem to be anything wrong. "This is textbook," he says. "This is just a normal looking colon, beautiful looking folds, normal blood vessels."

Then he finds a series of six tiny polyps. "I plucked them out," Dr. LaPook says. "We never roll the dice in medicine." He then sent off the six polyps to a pathologist to analyze, to see if any of them were dangerous.

How did Nate feel when he woke up after the procedure? "I didn't feel anything," he says. "It was simple."
Dr. LaPook says Nate is cancer-free.

Dr. LaPook has good news to share with Nate. All of the polyps were totally benign, and they didn't have any risk of developing into cancer.

While Dr. LaPook would usually recommend waiting 10 years between colonoscopies, he says Nate's family historyhis brother and grandfather died from colon cancerindicates that he should probably get one in three years.

Dr. Oz says there's another reason Nate should be vigilant in testing. "African-Americans get colon cancer earlier. It's more aggressive when they get it, which means they die more often from it. We don't want to miss it."
Peggy is a tanning addict.

Like an estimated 28 million Americans, Peggy visits tanning booths. She says she's been going to them for 23 years, as often as five times a week. "I always love to be tan," she says. "I love the feeling, the coloring, the way I look. It's part of how I envision myself. I don't even know my natural skin color anymore because I've been tan for so long."

Dr. Oz says Peggy is addicted to tanning. While there is some amount of sun that is healthy, Peggy's exposure goes far beyond that amount. "Think of the skin like a cup," Dr. Oz says. "You fill it up with water, being the sunlight. The sun brings you life-sustaining nourishment. It's your ally. When you fill it too far, it begins to overflow. And I think you've reached that limit."

So after years of excessive tanning, Dr. Oz arranged for Peggy to have her first ever skin cancer screening with dermatologist Dr. Brandith Irwin. "I'm probably like a poster child for someone who needs to go to the dermatologist and hasn't," Peggy says.
A, B, C, D of skin cancer

After taking Peggy's medical history, Dr. Irwin begins a skin cancer examination. In checking literally every centimeter of Peggy's skin from her scalp to between her toes, Dr. Irwin found several irregular spots on Peggy's arm and foot. After numbing those areas, Dr. Irwin removed the spots and sent skin samples to a lab to test if they contained any cancerous cells.

Dr. Oz says if those spots are skin cancer, which is the most common form of cancer, there are several types it could be.

Basal cell cancer, which starts at the base of the skin, is the most common form. Typically caused by sun damage, it starts with a scaly area that, if it advances, will eventually gain a pearly appearance.

Squamous cell tumors get a scaly appearance early. As they advance, the skin puckers in.

The third type of skin cancer is melanoma, which Dr. Oz calls "the big one." Melanoma comes from melanin, the cells that make pigment, so there are a few indicators. These can be explained as "A, B, C, D."

Asymmetry: "It's hard to draw a line down the middle," Dr. Oz says.

Border: "The border's irregular and it sort of melts into the skin around it. That's a classic sign of a melanoma."

Color: If a mole has a "rainbow coalition" of colors, that means it's probably melanoma, Dr. Oz says.

Diameter: Dr. Oz says mole size does matter. "If you can cover over the mole with an eraser head you'll probably be okay," he says. "But if you've got hundreds of moles or a family history or you've had a melanoma in the past, you need to be screened pretty aggressively."
Peggy is cancer-free.

Dr. Irwin is worried Peggy has basal cell or squamous cell skin cancer. "I think your skin is telling you that it's in distress," she tells her. "And you're starting to develop some early changes, possibly skin cancers, in your skin."

When the tests come back, they are negativeall of the tumors are benign. But with the way she has treated her skin for so many years, Dr. Oz says Peggy is very lucky. "It's not because you planned it to be that way," he says.

Dr. Oz says learning the proper way to screen for skin cancer can literally save a life. "And here's the fun part. You've got to get completely naked. It's fun to do it in pairs. Get a nice Chianti. And then you've got to get a camera out," he says. "And the reason to get the camera out is when you find things, skin things, to take pictures of, you've got to snap them. And put a dime next to them or some piece of coinage so you can see how big it wasthe key for [your dermatologist] to find out what they are."
Jennifer after surgery to remove melanoma

Just like Peggy, 40-year-old Jennifer had a dangerous love affair with the sun. "I was a sun worshipper ever since I was a teen. I went to the beach every chance I got. I used baby oil instead of sunscreen. I loved when I got sunburned, because I knew I'd be tan in a few days. Being tan made me feel beautiful, confident and healthy."

All the fun in the sun caught up with Jennifer when melanoma was found on her cheek and had to be surgically removed. "You can see how disfiguring it can be, especially if it begins to invade through the skin," Dr. Oz says.

Jennifer has a few words of caution for Peggy. "I was just like you. I'm paying the price now. You have to respect yourself enough to stopand your family and your friends. I was really lucky, my melanoma didn't spread. It doesn't mean that in two years it won't be everywhere. I have to live with that every single dayjust because I wanted a tan. And it's just not worth it. You do not need to do this to yourself. You're beautiful. You do not need to be tan."
Sandra is 43 and has never had a mammogram.

When Sandra was only 16-years-old, her mother died of breast cancer. "When she got sick, it just took the whole life out of the house. Nothing was the same, and none of us were the same," she says. Sandra is now 43 years oldthe same age she says her mother was when she had terminal breast cancerbut she has never had a mammogram. "What I'm doing is completely wrong, and I'm very ignorant. I'm very surprised at myself, but I just don't want to know. I've never been checked and there could be something. What happens if they do find something?"

Sandra's sister Josephine has been urging her to get a mammogram for years. "I send her e-mails. I send her cards. There was a special card they made one yearyou know, to remind someone you love to go and have an exam." But Sandra's fear kept her away from the doctor. "Every year I get that, 'Go get your mammies grammed' or whatever and I just laugh and I delete it. I mean, I don't even do a self-check."

Sandra is now facing her fears and going with Dr. Oz to have her first mammogram. "I'm going. I can't back out now. I'll just see what happens. I'm not going to like itbut I'll go."
Dr. Joseph gives Sandra a breast exam.

Dr. Oz takes Sandra to meet his colleague, Dr. Kathie-Ann Joseph, a breast surgeon at New York-Presbyterian Columbia Hospital. "You should be congratulated for coming in today," Dr. Joseph says. "I see dozens of women come in every day into my office, and they're just like you, so you're not alone."

Dr. Joseph begins the breast exam by checking Sandra's breasts for irregularities. "I'm checking all parts of the breast," Dr. Joseph says. "We sort of divide the breast into what we call quadrants. Divide it like a clock into fourths."

The breast exam goes well and Dr. Joseph gives Sandra the good news. "Your exam was fine. I didn't feel anything abnormal. Your lymph nodes were clear. I didn't feel any lumps."

Next, Sandra is given her first mammogram while Dr. Joseph urges her to relax. "Even if you hit me over the head I wouldn't be able to relax," Sandra says. "I'll feel better when I know everything's okay."
Dr. Oz's breast cancer animation

Dr. Oz shows an animation to demonstrate how breast cancer forms and why mammograms and breast exams are so critical. "There are about 15 or 20 lobes in an average breast. And they have lobules in them. The lobules make the milk that feeds and nourishes the child. And the milk goes from the lobule to the nipple via these ducts. Those ducts become the roads that are so important in transferring the milk. But they also can be the source of cancer."

Dr. Oz says that 85 percent of all breast cancer happens in those ducts. "But if you look inside the duct when the cancer is first beginning to start, it stays there for a while. It doesn't break through these walls like that. It takes a while to do that. If you can find the cancer when it's early, you can take it out and it's done."

What you don't want, Dr. Oz says, is for cancer to spread to the lymph nodes and beyond. "The key is to get that cancer before it penetrates through the wall. If you find it then, it's a done deal," he says. "You have a baseline defense systeman immune system. You want to help it, but it can only defend you for so long."
Sandra receives her results.

Sandra's brave decision to finally get a baseline mammogram has a promising endinga healthy breast report! "The story is much bigger than the fact that it's normal," Dr. Oz says. "Especially in a mammogram, the most beautiful part of the whole story is you have a baseline. If we know what your unique look is in your breasts, then we actually know five years down the road that that new thing we're seeing is different from what it used to be."

"I should have went a long time ago instead of bringing 50 million people with me," Sandra says. But because Sandra saw breast cancer take her mother's life, she needed convincing to take the first step. "I watched a woman deteriorate in front of my eyes, and I just didn't want to do that to my children."

Dr. Oz says if we can overcome the intimidation or fear, the more we know about our bodies, the better our overall prognosis will be. "When you're on a plane and you're bouncing around a little bit, you don't want to go up to the cockpit and see what's going on, right? Because it's scary to you. You figure someone else will take care of it," he says. "You've got to be the driver of your ship. You've got to be the world expert on your body. Not knowing if you've got the problem is not going make it any better. It actually makes it more difficult for [doctors] to help."
Karen and Jason

Last year, Karen wrote to The Oprah Show to stage an intervention for her overweight husband, Jason.

"I eat a lot of candy at night trying to keep awake 14 hours at a time," Jason said. "I feel like a 45, 50-year-old man in a 30-year-old body."

Jason also had a snoring problem so severe that it worried Karen. "It sounds like he's gasping, that he's actually not breathing for a couple seconds at a time, and I can't imagine what that might be doing to his heart," Karen said.

Dr. Oz gave Jason a big wake-up callat just 35-years-old, Jason had diabetes and hypertension.

Eleven months have now passed since Jason's interventiondid he change his health habits?
The new Jason

Jason is backand 70 pounds lighter! Jason says he read Dr. Oz's book, You on a Diet, to help him develop a healthier lifestyle. "I wouldn't even call it a diet," Jason says. "I learned how to self-educate myself on how to eat properly. Everybody knows you shouldn't eat the fast food and the candy, but what I didn't know was white bread. I switched to whole wheat, and a lot of things like that just help your metabolism speed up. And instead of candy at night, I eat fruit. I have more energy."

Dr. Oz has great news for Jason. "You're not a diabetic anymore, and you're not hypertensive anymore," Dr. Oz says. "The big story is these are reversible diseases. I just want to shout out to Karen, because that's the woman who saved your life."

What about Jason's snoring problem? Jason had an operation performed on his septum to control his sleep apnea, but his doctor found something unexpected. "We thought it was really nothing, a cyst, and we took it out. It turned out to be cancer," Dr. Josephson says.

Fortunately for Jason, Dr. Josephson was able to catch the cancer before it grew. "This is the kind of stuff we're talking about," Dr. Oz says. "You can change your health destiny. Those are not pretty cancers when they grow."