The number of cancer cases and deaths worldwide will nearly double by 2030 if measures aren't taken now to prevent the disease, a new report suggests.

There were about 12.7 million new cases of cancer , and 7.6 million cancer deaths around the world in 2008, according to the American Cancer Society report. Those numbers are expected to rise to 21.4 million new cases annually and 13.2 million deaths over the next 20 years, the report said.

The expected increase will largely be due to a growing and aging population, but unhealthy lifestyles that include smoking, eating poorly and physical inactivity contribute as well, said Melissa Center, an epidemiologist at the American Cancer Society.

Developing countries, in which people are increasingly adopting these unhealthy lifestyles, could learn a lesson from higher-income nations that are already plagued with high rates of preventable cancers, Center said.

Developing countries "have a unique opportunity to avoid the same tragedy by curbing the epidemics at early stages," Center told MyHealthNewsDaily.

The figures in the report were based on the International Agency for Research on Cancer global database. The database includes health information for 11 percent of the world's population.

The report was published today (Feb. 4) in CA: A Cancer Journal for Clinicians.

High-risk behaviors

About 2.6 million of the 7.6 million cancer deaths in 2008 could have been prevented by curbing smoking, certain infections and alcohol consumption, according to an editorial accompanying the report.

Smoking in particular has a lag time before repercussions appear. People who start smoking in their 20s may not develop lung cancer until their 40s or 50s.

The effects of smoking, which are now seen in high-income countries where smoking peaked two decades ago, could increase the future number of cancer cases in developing areas where smoking is only now starting to become more prevalent, Center said.

"This is major concern, and the very reason why comprehensive tobacco control programs are so important in Africa and other developing regions of the world," she said.

Lung cancer rates are decreasing the United States, but increasing across the board in Africa and Asia. Lung cancer is also increasing in young women in Spain, France, Belgium and the Netherlands, which suggests the cancer rate will increase over the next few decades if no interventions are made, the report said.

Smoking was also blamed for the slow U.S. life expectancy growth over the last two decades, according to a report released Jan. 25 by the National Research Council.

Accounting for cancer

Cancer rates vary across countries, according to the report. In economically developed countries, the most common cancers in 2008 for men were prostate, lung and colorectal cancers, and were breast , cervical and lung cancers for women, the report said.

But in economically developing countries, lung, stomach and liver cancers were most common in men. Breast, cervical and lung cancers were also the most common in women, the report said. Stomach, liver and cervical cancers can be prompted by bacterial or viral infections.

That means 1 in 4 cancers in developing countries are infection-related, compared with fewer than 1 in 10 in developed countries, the report said.

The number of cancer cases in less-developed countries could also increase if screening opportunities became more widely available there, she said.

"Many cancers in developing areas currently go undiagnosed due to limited resources and other pressing public health problems," including HIV/AIDS, malaria and tuberculosis, she said.

But any future increase in diagnosed cancer cases brought about by increased screening would eventually plateau, because people would be diagnosed at earlier, more treatable stages of disease, she said, thereby reducing cancer deaths.

"Increased screening opportunities would need to go hand in hand with increased awareness of early signs and symptoms of cancer among the public and health care providers," Center said.

Pass it on: Cancer cases and deaths around the world could nearly double by 2030, largely due to an aging population. But unhealthy lifestyles that include smoking, poor diet and physical inactivity can exacerbate the cancer rate.

Follow MyHealthNewsDaily staff writer Amanda Chan on Twitter @AmandaLChan.