A new report from the American Cancer Society says cancers associated with lifestyles and behaviors related to economic development -- including lung, breast, and colorectal cancers -- will continue to rise in developing countries if preventive measures are not widely applied.

The finding comes from the second edition of Global Cancer Facts & Figures and its academic publication, Global Cancer Statistics, published in CA: A Cancer Journal for Clinicians. Both publications were released on World Cancer Day, Feb. 4, 2011. 

Increasing cancer

According to estimates from the International Agency for Research on Cancer (IARC), there were approximately 12.7 million new cancer cases worldwide in 2008 -- 5.6 million of which occurred in economically developed countries and 7.1 million in economically developing countries.

There were approximately 7.6 million cancer deaths worldwide in 2008, 2.8 million of which occurred in economically developed countries and 4.8 million in economically developing countries. By 2030, the global cancer burden is expected to nearly double, growing to 21.4 million cases and 13.2 million deaths.

And while that increase is the result of demographic changes -- a growing and aging population -- it may be compounded by the adoption of unhealthy lifestyles and behaviors related to economic development, such as smoking, poor diet, and physical inactivity.

Preventable deaths

An accompanying editorial (appearing in CA:) by Otis W. Brawley, M.D., chief medical officer of the American Cancer Society, says about 2.6 million of the 7.6 million cancer deaths that occurred in 2008, or about 7300 cancer deaths per day, were potentially avoidable through the prevention of known risk factors, including tobacco use, dietary factors, certain infections, and alcohol use.

"The worldwide application of existing cancer control knowledge according to the capacity and economic development of countries or regions could lead to the prevention of even more cancer deaths in the next 2 to 3 decades," writes Dr. Brawley. "In order to achieve this, however, national and international public health agencies, governments, donors, and the private sectors must play major roles in the development and implementation of national or regional cancer control programs worldwide."

Cancer rate comparisons

A comparison of cancer rates reveals differences in cancer causation between economically developed and economically developing countries. In economically developed countries, the three most commonly diagnosed cancers in 2008 were prostate, lung, and colorectal cancers in men and breast, colorectal, and lung cancers in women. In economically developing countries, cancers of the lung, stomach, and liver were most frequently diagnosed in men while breast, cervical, and lung cancers were the most commonly diagnosed in women.

Two of the three leading cancers in men (stomach and liver) and one of the three leading cancers in women (cervix) in developing countries are related to infection. Overall, about one in four cancers in developing countries are related to infection compared to fewer than one in ten in developed countries.

Shifting trends

The report also outlines shifts in cancer trends that point to the increasing impact that unhealthy behaviors are beginning to have in developing countries. While male lung cancer death rates are decreasing in most Western countries, they are increasing in China and several other countries in Asia and Africa where the tobacco epidemic is in earlier stages and smoking prevalence has not begun to drop, or even continues to increase.

Lung cancer rates in women, which have plateaued in the US, are increasing in many countries, notably in Spain, France, Belgium, and the Netherlands, where rates are up among younger women -- suggesting lung cancer in females in these countries will likely increase for several decades barring major interventions.

Breast cancer is now the leading cause of cancer death among females in economically developing countries, a shift from previous decades during which cervical cancer was the most common cause of cancer death. Colorectal cancer incidence rates, which have been decreasing in the US, are rapidly increasing in several countries historically at low risk, including Spain and a number of countries within Eastern Asia and Eastern Europe.