Here are just some of the things that surprised me. First, skin cancers are really common, even compared to what I thought: over 1 million new cases are diagnosed a year in the United States. However, almost all of these are nonmelanoma cancers, which are much less lethal than melanoma. In fact, less than one in a thousand nonmelanoma skin cancers lead to death, while about one in eight melanomas are lethal.

Another thing that took me off guard was the impact of pancreatic cancer. In 2009, there were 42470 people diagnosed with pancreatic cancer. Sadly, an estimated 35240 people died of pancreatic cancer. That means that in spite of much lower incidence rates, pancreatic cancer is the fourth cause of cancer death, after lung, colorectal, and breast cancers. Even including melanomas, the million skin cancers a year lead to far fewer deaths than pancreatic cancer. This shocked me, so I took a closer look. Overall, the five year survival rate for patients diagnosed with pancreatic cancer is around 5%, which makes pancreatic cancer a formidable disease. My heart goes out to those that are struggling with pancreatic cancer.

Apparently, a major challenge with pancreatic cancer is diagnosis. Usually, symptoms appear late in the disease, after treatments might be effective. Also, screening with current techniques is either too invasive or not sensitive enough to warrant general use. As with other cancers, research is being conducted to find better treatments, risk factors, better screening techniques, and preventative measures. Hopefully one day we can get to the point where pancreatic cancers are as dangerous as a nonmelanoma skin cancer.

To learn more about common cancers, you can go to the National Cancer institute at www.cancer.gov/cancertopics/commoncancers. It certainly got me thinking!

In the fall of 2009, the World Health Organization published a 10 year study which examined the cell phone habits of more than 120,000 people in 13 countries. The study reported a significantly higher risk of developing brain tumors in individuals with 10 years or more of cell phone usage. Similar findings in other studies have added to the growing concern over long-term exposure to cell phone usage.

In 2007, Dr. Lennart Hardell, from Örebro University in Sweden, reported an increased risk of malignant glioma in cell phone users, and that a daily one hour exposure significantly increased the risk for developing a brain tumor after 10 years. Recently, Dr. Ronald B. Herberman, director emeritus of the University of Pittsburgh Cancer Institute delivered a memo to over 3000 staff and faculty members, essentially warning them of the health risks of cell phone use, and specifically stated that children should limit cell phone use to emergencies only.

So why aren’t cell phones packaged with health warning labels in the same way that alcohol and cigarettes are labeled? The jury is out on whether the cell-phone and brain tumor link is convincing enough to warrant major concerns. In fact, the number of studies that render the link inconclusive far outnumber the studies which do (arguably, though, we can exclude studies funded by telecommunication companies). Discrepancy in these findings is due in large part to the inherent bias found in case-control studies, which are designed to examine specific factors that may contribute to a disease process or illness by comparing similarly matched individuals, those with and without the medical condition in question. In this case, the studies essentially rely on the participant’s recall of cell phone usage patterns as far back as 10 years.

Further substantiation of the clinical health risks posed by cell phone usage will need to include cohort studies, where healthy individuals, with and without exposure to cell phones are followed over a period of time and examined for occurrence of brain tumors. This of course means that it will take years to adequately determine the health risk. In the meantime, it may serve us well to heed recommendations to limit exposure to the electromagnetic radiation emitted by cell phones.

References:

http://artpredator.files.wordpress.com/2009/03/cell-phones-on-planes.jpg

http://www.webmd.com/cancer/brain-cancer/news/20091203/cell-phones-and-brain-tumors-no-connection

http://www.ncbi.nlm.nih.gov/pubmed/17409179

http://www.post-gazette.com/downloads/20080722upci_cellphone_memo.pdf

http://www.cancer.gov/cancertopics/factsheet/Risk/cellphones

http://www.medicalnewstoday.com/articles/161960.php

http://www.reuters.com/article/idUSTRE59C5GA20091013

http://www.newser.com/story/69023/report-revives-fears-of-cell-phone-tumor-link.html

http://www.physorg.com/news175853675.html

Needless to say, an animal that doesn’t get cancer is something worth studying. Why no cancer? It turns out that mole rat cells don’t “like” each other very much. Researchers discovered that when these cells are cultured, they stop dividing at lower cell densities than other cells. This growth arrest, which is called “contact inhibition”, is under the control of a gene called p16. When cells contact each other, receptor proteins sense the contact and activate p16. With p16 active, the cell cycle is inhibited. P16 acts very much the same way as p27, the gene that controls contact inhibition in people. Mole rats have p27 and p16. This double whammy keeps cells from growing too much, which is a hallmark of cancer.

Why this extra level of control? Mole rats live up to 30 years and continue to have offspring throughout life. This means that cancer could have an impact on their fitness. They also have another important difference from us. Most of the cells in us have a limited ability to divide. This is because the ends of the chromosomes, called telomeres, shorten every cell division. Once they are too short, the cells stop dividing. In mole rats, the telomeres don’t shorten. This is because mole rat cells express an enzyme, called telomerase, which lengthens the telomeres. Telomerase is usually activated in cancers, allowing them to divide without limit. Without a limit on the number of cell divisions by telomerase shortening, it seems that mole rats have evolved a different way to keep their cells in check.

The exciting thing is that we have p16, but it doesn’t seem to affect our cells the same way. If we can tweak cancer cells to react to contact like mole rat cells, we may be able to make them stop themselves!

The image of the mole rat was taken from the Animal Behavior Lab of Gray Lyons at Davidson College

The foods we eat also have a big effect. I think back on what my mother used to preach, and I think she had it right. She told me to eat my greens and have lots of fruit. On the other hand, somehow she knew too much alcohol, red meat, and sugary drinks are bad. “Where did all the ice cream go?” echoes from the past. My hiking and canoeing mother encouraged me to do sports and other outdoor activities. I knew these choices were healthy and protected me from heart disease. What I didn’t realize was that my mother was protecting me from cancer, too.

The World Cancer Research Fund has recommendations for how to prevent cancer. I think they interviewed my mom.

Here are some of them:
• Be as lean as possible in the normal range of body weight
• Be physically active every day
• Avoid “energy-dense” foods and sugary drinks.
• Eat lots of non-starchy veggies and fruit
• Limit red meat and processed meat in your diet
• Avoid salt

You can check out the details and see the whole list on their web site:

http://www.wcrf.org/research/expert_report/recommendations.php

Now that I have passed on my mother’s preaching, you have yet another reason to eat well and exercise. I’m off to the gym… to fight cancer and heart disease at the same time!

HPV is not only limited to cervical cancer, but has also been implicated in squamous cell carcinomas of the head and neck regions (HNSCC) and includes oral, tonsillar, and oropharyngeal tumors—which have usually been associated with long term alcohol and tobacco usage. The incidence of HNSCC has risen steadily over the last 20-30 years in younger patients, and about 20% of these carcinomas are HPV positive with HPV type 16 emerging as the most prevalent subtype present in these tumors.

However, unlike the clinical regimen for cervical carcinoma which includes HPV typing of the tumor tissue, there are currently no standard molecular tests utilized as part of the clinical treatment protocols for head and neck cancers. Prognostic factors for survival include molecular diagnostic testing for cytokines, proteomic profiling, and testing for the presence of HPV.

Interestingly, the detection of HPV in  head and neck cancer is a favorable prognostic marker; HPV positive tumors are biologically distinct from HPV negative tumors which are typically associated with long-term tobacco and alcohol use. This favorable prognostic factor in younger patients with HPV positive tumors may be attributed to the lack of p53 mutations found in younger patients, and thus improves chemotherapeutic treatment response in these patients, in part because the efficacy of chemotherapy depends upon a functional p53 gene that mediates apoptosis (programmed cell death) in response to radiation and chemotherapy.

Note: the thumbnail above shows visibly HPV-infected cells

You may not know this, but dogs can actually smell some cancers. It doesn’t even take a sophisticated sniffer dog to do this: even some household dogs can be trained to tell the difference between the odor of a normal person and that of a person with lung cancer. In theory, your dog Max could be a living cancer detector, letting you know early on that you are at risk.

Dogs also get cancers. If fact, cancer is the number one killer of dogs, and about one in three dogs get cancer. Every year, almost a million dogs die of cancer in the United States. Often, cancers in dogs are treated with the same treatments that are used in humans. This is because dogs and people are very similar, so many of the drugs developed to treat people work on dogs. This summer, the first cancer drug specifically for dogs was approved by the FDA. The drug, called Palladia, shrinks the size of mast cell tumors by killing tumor cells and cutting off their blood supply. If you are a dog owner, this may be reassuring: at least one drug has now been tested on dogs before it goes into use.

Dogs and their owners are now being called into service in a different way. In an effort to speed up testing of promising drugs, some experimental cancer drugs are being offered to owners with afflicted canines.

Of course, some people will think that using pets as “guinea pigs” in experiments (sorry guinea pig lovers…) is unethical. Even though researchers will make the well-being of the dogs a priority, it is difficult to predict the outcome of these experiments. With luck, the dogs will benefit and the new drugs will be made available to people sooner than they would be otherwise. For those unlucky dogs that don’t benefit, my thanks, much as I thank the brave people who take experimental drugs.

I’m a bit of a coffee drinker, so I often wonder if this is good or bad. Growing up, it was always presented as a vice. Yet, I have been drinking coffee all my life- and coffee has thousands of chemicals in it. Should I try to quit, or am I all right? Given all the chemicals, I have worried that I might be exposing myself to a cancer causing chemical- a carcinogen. Recently, a few reports have looked into this. On the whole, coffee comes out all right.

The best evidence for a good effect is on liver cancer: a Japanese group showed that drinking coffee decreases your risk of getting liver cancer around 43%! The American Cancer Society estimates that there will be around 22, 620 new cases of liver cancer this year. A quick bit of math makes me think that we should be able to prevent thousands of these cancers by getting everyone to drink coffee!

Here is my admittedly sloppy calculation:

The National Coffee Association reports that 54% of American adults drink coffee daily. If the risk of getting cancer is about 43% lower and 54% of American drink coffee day, it seems to mean that the coffee drinkers only make up a small proportion of the liver cancer patients.

The proportion, I think, is .54 times .57, or .3078. That means that only around 7000 of the new liver cancer cases are coffee drinkers if my calculations are right (.3078 times 22620 is 6962). That leaves over 15000 non-coffee drinkers. What if they had been coffee drinkers?

If we look at the 22,620 cases, how many should come from coffee drinkers? .57 times 15657 is 8925…. If my sloppy math is right, that means that there could have been 6700 fewer cases of liver cancer this year if everyone drank coffee every day. Of course, many find drinking dirty brown water unpleasant, but it makes you think…

There is also evidence that coffee reduces the risk of kidney cancers, some breast cancers, and ovarian cancer.

It is nice to know my morning indulgence is unlikely to be making me sick, and that  coffee is probably  good for you in many ways. Check out this article at the National Institutes of Health to find out more:

The news is not all good: it seems that drinking hot beverages including coffee can increase the risk of esophageal cancer. Maybe I should start drinking my coffee cold…

For information on some things that might not be good for you, check out Inside Cancer’s section on Causes and Prevention of cancer.