The number of people in the United States who have survived cancer is set to reach nearly 18 million in the next decade, up from 13.7 million currently, said a US study out Thursday.

The number of survivors is growing because of better treatments and an ageing and expanding population, even as the overall rate of cancer is falling, it said.

The research appears in CA: A Cancer Journal for Clinicians, and was compiled by the American Cancer Society and the National Cancer Institute.

Nearly half of US cancer survivors are 70 or older, and 64 percent were diagnosed five or more years ago, said the report.

The median, or midpoint age for patients at the time of diagnosis was 66.

Young cancer survivors were more rare -- only five percent of the US population that had beat cancer was younger than 40.

"There are 58,510 survivors of childhood cancer living in the United States, and an additional 12,060 children will be diagnosed in 2012," said the study.

The most common cancers among women in 2012 were breast (41 percent), uterine (eight percent), and colorectal (eight percent).

Among men, the most common were are prostate cancer (43 percent), colorectal cancer (nine percent), and melanoma (seven percent).

In the United States, there will be an estimated 1.6 million new cases of cancer in 2012 and 577,000 deaths, according to projections by the American Cancer Society.

[A U.S. cancer patient gets chemotherapy treatment in 2010. AFP Photo / Chris Hondros]