The cost of treating cancer in the US has nearly doubled over the past two decades, mainly driven by the increasing number of cancer patients, a new study has found.

Cancer treatment costs rose from nearly $25bn in 1987 to more than $48bn by the end of 2005, said the Centers for Disease Control and Prevention’s Florence Tangka and lead author of the study.

The study compared data from national telephone surveys of 164,000 people done in 1987 and from 2001 through 2005.

Researchers discovered a dramatic increase in the number of cancer cases covered by the government’s Medicare and Medicaid programmes, according to seattlepi.com.

Cancer accounts for 5% of total US medical costs, which has not changed in the last few decades, according to the study.

Private insurers now cover up to 50% of cancer treatment costs, compared to 42% in 1987.

During the same period, the proportion of cancer costs paid by patients has fallen from 17% to 8%, researchers said.

The study also revealed that newer treatments along with wider testing are driving up the overall cost of cancer care.

Emory University health policy researcher Kenneth Thorpe said that increased cancer care costs cover better treatment which means more Americans are surviving cancer.

“It seems like we’re buying increases in survival,” he said.