Developed Countries Still Carry Greatest Cancer Burden

But study finds developing nations are catching up

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HealthDay Reporter

THURSDAY, March 10, 2005 (HealthDay News) -- The developed world still bears the lion's share of cancer cases, but less developed areas are catching up.

Worldwide, lung cancer is the most common and deadliest cancer.

That's the message from Global Cancer Statistics, 2002, which appears in the March/April issue of CA: A Cancer Journal for Clinicians.

"One important aspect is the increase in the cancer burden in developing countries, which is because of adopting a more Western lifestyle like increased smoking, different dietary patterns and less physical activity," said Ahmedin Jemal, program director for cancer occurrence at the American Cancer Society in Atlanta.

The other key contributor is age. "Life expectancy is increasing in lesser developed countries, and historically cancer has been a problem of developed countries, but that might be changing. As people tend to live longer in developing countries, the burden of cancer is expected to increase," Jemal said.

"You've got two choices. You get old or cold," added Dr. Jay Brooks, chairman of hematology/oncology at Ocshner Clinic Foundation in New Orleans.

The International Agency for Research on Cancer assembled estimates of the global cancer burden for the past 30 years, focusing on the number of new cases, death rates and prevalence, or the number of people alive with the disease.

Overall, the report found large differences in the rates of different cancers, depending on the part of the world.

In 2002, there were 10.9 million new cases of cancer, 6.7 million deaths and 24.6 million people alive with cancer within three years of diagnosis.

The report authors found little difference in mortality between developing and developed countries. The chance of a man dying from cancer before he turns 65 is 18 percent higher in developed countries. Women in developing countries actually have a higher chance of dying than women in developed areas.

Continuing a trend that began in 1985, lung cancer is still the most common cancer, with 1.35 million (12.4 percent) of new cases, and also carries the highest mortality rate (1.18 million deaths, or 17.6 percent of the world total). "The biggest issue is tobacco," Brooks said. "It's just phenomenal."

Breast cancer is the second most common cancer (1.15 million new cases), but the fifth-highest cause of death, thanks to a relatively good prognosis once diagnosed.

After lung cancer, the most common causes of cancer death are stomach cancer and liver cancer. The most prevalent cancer in the world is breast cancer, with 4.4 million survivors.

Almost half (49.9 percent) of all lung cancer cases occur in developing countries. In 1980, by contrast, 60 percent occurred in these areas of the world. The highest rates in men are in North America and Europe, particularly Eastern Europe. The incidence is lower in women, with the highest rates in North America and Northern Europe. The incidence is also high for both men and women in China, as well as in Australia and New Zealand.

Breast cancer is the most frequent cancer in women (representing 23 percent of all cancers), with more than half of all cases in industrialized nations. That high incidence is likely due to better screening techniques. The average prognosis in developed countries is 73 percent; in developing countries it is 57 percent, the report said.

Cervical cancer is the seventh most common cancer overall and the second most common cancer in women.

Most (83 percent) of new cancer cases occur in the developing world. China had the highest number of new cancer cases (2.2 million, or 20.3 percent of the world total). North America had 1.6 million new cancer cases (14.4 percent of the total).

The risk of being diagnosed with cancer, whether you are a man or a woman, is highest in North America. The risk of dying, however, is highest for men in Eastern Europe and for women in northern Europe. In general, mortality rates are higher in lesser developed areas, the study found.

"There's a limited capacity to treat," Jemal explained. "Few developing countries have radiation facilities. That will compound the problem."

More information

For more on different types of cancer, visit the American Cancer Society.

SOURCES: Ahmedin Jemal, Ph.D., DVM, program director, cancer occurrence, American Cancer Society, Atlanta; Jay Brooks, M.D., chairman, hematology/oncology, Ochsner Clinic Foundation, New Orleans; Global Cancer Statistics, 2002

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