What is the polycythemia vera life expectancy?

What variables correlate with cancer incidence rates across nations (other than life expectancy)?

• Life expectancy can be seen to be correlated with cancer incidence rates () But is it the only variable? It appears not. Consider the case of the following countries and their associated life expectancies, and cancer rates (per 100k) from http://globalcancermap.com/: US (78 years): 300 Germany (80 years): 282 Austria (80 years): 232 Japan (83 years): 201 I cherry picked countries whose expectancy differences can be assumed to be within the noise. Now this 300 vs 201 is a very substantial difference (in fact, the trend in the opposite direction to the expectancy argument, if you decide to think of 78->83 as being non-noise differences). Of course one has to consider not just the expectancy but the distribution of the population (http://en.wikipedia.org/wiki/List_of_countries_by_median_age), because then you can calculate the number of people in each age bracket. But Japan is still curiously different from the US: they have high life expectancy, their population demographic (going by median age) is almost the oldest, yet their cancer incidence is a third lower!

• Answer:

  1. Cancer is a disease of aging. So countries with the highest life expectancies will tend to have the highest rates of cancer. Contrary to what is commonly quoted about life expectancy among countries, America has among the highest life expectancies in the world if, and it's a big if, one discounts deaths due to societal issues (deaths due to violence and premature births which is more common with mothers in their early/mid teens). America has a disproportionate amount of premature teen related births compared to European countries. Having said that, the cancer rates for the top 10 are very close and all are a result of living the lifestyle and eating the diet of industrialized nations. 2. Lifestyle and diet. Industrialized nations tend to have rich country diets and rich country lifestyle. That is adults who are sedentary at their work and diets that are rich in meat and fat. This has led America to the so-called epidemic of obesity. Obesity is thought to be responsible for about one third of cancers in America. The poorer countries tend to have adults who are much more physically active and until the relatively recent advent of fast food chains, tended to eat a poor person's diet which is healthier (less meat, lots of whole grains and vegetables). Poorer countries have a had a lower obesity level. There is speculation that that will change with cheap fast food chains. 3. Americans tend to survive heart disease. Everyone here is on a statin, we're aggressive with stents and bypass surgeries. At the end of life, most of us in industrialized countries die of cardiovascular disease or cancer. So Americans get cancer. 4. People that survive one cancer, have a higher chance of getting another because the same lifestyle factors affect many cancers. American patients have among the best cancer outcomes in the world. We generally diagnose cancers earlier and treat cancers more aggressively (some say too aggressively-see recent PSA and mammogram recommendation from the U.S. preventative services task force in 2011). This has been demonstrated in studies comparing size of breast cancers diagnosed in the U.S. versus Canada and better survival of colon cancer in the U.S. versus Canada. England has the lowest survival for cancer of any Western European nation and has had several attempts at revamping the delivery of cancer treatment there. I don't mean to offend Canadians and the British. This has been well reported and debated. So in my practice, I sometimes see patients that have survived two, three, and sometimes even four different major cancers. 5. Reporting. All major cancers in America are by law reported to a national registry. The hospital cancer programs are certified based in large part on the quality of data collected for the national registry. Other industrialized countries tend to do the same. So a higher reporting rate is going to get you a somewhat higher number of cancers. 6. Japan is going to catch up. Their breast cancer rates are starting to rise as a result of becoming highly industrialized for the past 3+ decades. No more women farmers, no more diets of fish and vegetables, lots of Pizza Huts and McDonalds, low birth rate and late birthing age are contributing to the rise. So that's my thoughts. I'm sure there will be disagreements and other factors I've missed.