Lung cancer, women, rich nations: What's the connection? (REPORT)

Breast cancer has been the most common type of cancer in women in developed countries until now - lung cancer has surpassed it, according to a new report released Wednesday.

The American Cancer Society in collaboration with the International Agency for Research on Cancer (IARC) finds lung cancer has surpassed breast cancer as the leading cause of cancer death in females in developed countries. The authors of the report say the change reflects the tobacco epidemic in women, which occurred later than in men.

Lung cancer has been the leading cause of cancer death in males in developed countries for several decades.

"We're seeing the deaths now" from lung cancer due to a rise in smoking by women three decades ago, said Lindsey Torre of the American Cancer Society.

Globally, there has been an estimated 14.1 million new cancer cases and 8.2 million cancer deaths occurred in 2012. In the United States, there were

"Developing countries account for 57 percent of cancer cases and 65 percent of cancer deaths," Torre said.

Meanwhile, Smoking rates have leveled off or dropped in rich countries. In the United States, "we are already seeing lung cancer death rates decline," Torre said.

The reports rely on the worldwide estimates of cancer incidence and mortality produced by the IARC for 2012 in their GLOBOCAN series.

Torre urges smokers to quit as soon as possible. Quitting by middle age can avoid 60 percent of the risk of dying of lung cancer, Torre said.