Cancer is named from the place it originates. This makes a difference on what type of treatments will be effective. Being diagnosed with cancer of the unknown primary (CUP) means that cancer has been found in the body but the place of origin is unknown.

If later, the place of origin is found then the type of cancer diagnosis changes from an unknown primary to the specific organ or body area that the disease first began.

Some cases of cancer of the unknown primary are unfortunately never found. Physicians will then decide on the best course of treatment based on two factors: The way the cells look under the microscope and which organs are currently involved.

Statistics and Prognosis:

The exact number of cases of this disease is not known. It may be about 2% to 5% of all cancers in the United States. It is found more often among men than among women. The average age of people with this cancer is about 60 years.

This is a very dangerous cancer. Only half of patients will live 9 to 12 months after their cancer is found. There are several reasons why this cancer is so serious. First, most of these are fast-spreading cancers. Second, because the exact type is not known, it is harder for doctors to know what treatment is best. Also, the cancer is often widespread, making it harder to cure.

In recent years, microscopic and other diagnostic techniques have improved dramatically. For this reason, doctors can now determine the primary site in about four out of five cases.

October 30, 2006 marked the launch of our series Cancer by the Numbers. Our intention was to give individual attention to each and every cancer, to raise awareness of the multitude of cancerous diseases that seem to consume our population, to answer questions and pose questions, and to initiate discussion among readers. I think we are accomplishing what we set out to do. Still, we have a lot of ground to cover. Since that October day last year, we have featured 13 different cancers. That's a lot. And not a lot, when you consider how many different strains of one disease really exist.

I am writing today to reaffirm our commitment to Cancer by the Numbers. These posts will appear at least twice per month -- so be on the lookout. Until the next one appears, though, take a look back at what we have to offer in one of our most comprehensive and researched Cancer Blog series. Here they are:

Cancer by the Numbers: Basal Cell Carcinoma
Cancer by the Numbers: Osteosarcoma
Cancer by the Numbers: Hodgkin's Disease
Cancer by the Numbers: Gallbladder Cancer
Cancer by the Numbers: Glioblastoma Multiforme
Cancer by the Numbers: Melanoma
Cancer by the Numbers: Mantle Cell Lymphoma
Cancer by the Numbers: Liver Cancer
Cancer by the Numbers: Rhabdomyosarcoma
Cancer by the Numbers: Cervical Cancer
Cancer by the Numbers: Pancreatic Cancer
Cancer by the Numbers: Lung Cancer
Cancer by the Numbers: Testicular Cancer

If there's a cancer you'd like to see covered sooner rather than later, please leave us a comment and let us know.

My sister has skin cancer -- the basal cell variety. She has two spots, both on her chest, each one scheduled to be surgically removed in a few weeks. If it were me with this new diagnosis, I'm sure I'd be freaking out, maybe because I've already had breast cancer and tend to panic about any cancer or maybe just because I'm a worrier by nature. But my sister is taking her cancer news in stride, and I am too -- because now that I've done a little research, it seems this type of cancer is pretty easy to beat.

Here's a little refresher lesson on the skin: The skin is the largest organ in the body, and is made of three layers -- the epidermis (top layer), dermis (middle layer), and subcutis (deepest layer). For the purpose of this post, let's focus on the epidermis.

The epidermis has three layers -- an upper, middle, and a bottom layer. This bottom layer is comprised of basal cells. This is where basal cell cancer begins.

Overview of osteosarcoma:

There are about 900 new cases of osteosarcoma diagnosed in the US each year. About 400 occur in children and adolescents younger than 20 years of age.

Osteosarcoma forms in the bones. It is most commonly diagnosed in those who are 15 to 25 years of age. It is also the most common type of bone cancer, and the sixth most common type of cancer in children.

Other types of cancer can eventually metastasize to the bone, however this disease originates in the bone and can spread elsewhere to other parts of the body.

Many cases of osteosarcoma, around 80 percent, begin in or around the knee area.

What are the risks of osteosarcoma?

The disease is most seen in boys and can arise from unpredictable errors in the DNA of growing bone cells during times of intense bone growth. Currently, there is no effective way to prevent this type of cancer but with proper treatment most kids diagnosed with osteosarcoma do recover.

We're still basking in the hot sun, bronzing our bodies in tanning beds, and playing outdoors without slathering on the sunscreen. What will it take, I wonder, for our society to catch on, to take real steps toward preventing skin cancer?

It seems education isn't enough. Most of us know by now all it takes is one bad sunburn to increase our risk of skin cancer, yet we continue to collect burn after burn after burn. Perhaps like all habit-forming behaviors -- think smoking -- it takes something tragic in our lives to inspire change. When someone we know gets lung cancer after a lifetime of smoking or someone we know develops melanoma after years of sunbathing, maybe we get the hint. Maybe

Now, I know you don't personally know this young woman -- she calls herself Miss Melanoma -- but I suggest you read her story. And I recommend you take what happened to her -- she lost part of her foot to melanoma and is currently battling a spread of the disease -- and allow it to really sink in, allow it to motivate you to take cover from the sun, before something like this happens to you. Because it can.

My mom's best friend died from pancreatic cancer just three months after her diagnosis with the disease. One of my co-workers lost her mother to the same disease just weeks after diagnosis. Another co-worker's husband lost his battle with pancreatic cancer after a 15-month all-out fight. And a family friend has somehow been surviving this deadly disease for years now. He's the exception, defying the odds rarely in favor of long-term survival.

About 33,730 people will be diagnosed with pancreatic cancer in 2006. Many of them -- 32,300 -- will die from the disease that is rarely caught early. Pancreatic cancer is the fifth leading cause of cancer death in the United States.

In 2006, 174,470 people will be diagnosed with lung cancer in the United States. About 92,700 men and 81,770 women will develop the disease -- the leading cause of cancer death among both men and women.

An estimated 162,460 men and women will die of lung cancer this year, accounting for 28 percent of all cancer deaths and taking more lives than colon, breast, and prostate cancers combined. While most people diagnosed with lung cancer will die within the first two years of diagnosis -- this has not changed in 10 years -- some people are cured. There are currently about 333,000 long-term survivors.

Testicular cancer, cancer in one or both of the testicles, usually occurs in young men and will strike about 8,250 of these men this year. About 370 men will die.

A man's lifetime risk of developing this cancer -- that typically shows up in only one testicle -- is 1 in 300, securing it as one of the less common cancers in the United States. The chances of dying from testicular cancer are 1 in 5,000, making it one of the most curable forms of cancer. Yet it is still the most common form of cancer in men ages 15-34. It is also a cancer commonly characterized by denial and embarrassment. As a result, it is one of the least mentioned cancers.

All cancers are not treated equally. Some attract a frenzy of attention -- breast cancer -- and some receive not much attention at all -- gallbladder cancer. Some are vigorously researched and studied. Others sit by idly, rarely the subject of investigation. Some are feverishly funded. Some never prosper by way of financial support. Yet they all share something very important in common. They are all cancer.

All cancers are marked by an uncontrollable division and spread of abnormal cells. And they are all capable of delivering shock and despair and even death to any one of us. And that makes each one -- brain cancer, cervical cancer, colon cancer, eye cancer, liver cancer, prostate cancer, stomach cancer, you name it -- worthy of equal attention.

And so I bring to you Cancer by the Numbers, a series of posts that will feature the basics about all sorts of cancer, beginning with the numbers -- the statistics -- to help define the prevalence of each cancer, followed by important facts about screening, diagnosis, treatment, survival, and more. I will cover the well-known cancers, the sort-of-known cancers, the barely-known cancers. And while I can only offer what I can track down on each form of cancer, I intend to dish out every piece of data I can dig up -- so we all can become a little more informed, a little more prepared should we have to personally do battle with any one of the 100 possible cancers out there.

The American Cancer Society reports that 1,399,790 new cancer cases will be diagnosed in 2006. This estimate does not include most carcinoma in situ (noninvasive cancer) cases and also does take into account the estimated one million cases of basal and squamous cell skin cancers that will be diagnosed this year. Of these predicted cases, about 564,830 will result in death -- that's more than 1,500 people each day. Cancer is the second most common cause of death in the United States, exceeded only by heart disease, and accounts for one of every four deaths.

These numbers are staggering. But without further explanation, they are broad and all-encompassing and don't say much about how all the individual diseases add up. That's what I plan to do -- break it all down, cancer by cancer, until the numbers make sense. And the cancers do too.