The National Health Insurance Service (NHIS) said that the reimbursement claims for anticancer drugs last year amounted to about 1.91 trillion won ($1.6 billion), accounting for 9.3 percent of the total drug reimbursement payouts of 20.3 trillion won.

According to the NHIS, medical expenses for health insurance last year stood at 86.9 trillion won, and drug expenses accounted for 23.6 percent, with 20.3 trillion won.

"About 42.2 percent of drug expenses were spent on drugs for chronic diseases, with antiarteriosclerotic agent, blood pressure-lowering drugs, and diabetes drugs taking first, second, and fourth place among top drug cost shares," the agency said.

The agency stressed that asides from drugs for chronic disease, the cost of anticancer drugs had the second-largest amount of total drug expenditure with 1.9 trillion won.

"Compared to 2017, the number of reimbursement benefits for anticancer drugs increased by 26.8 percent, with 738,000 patients receiving such benefits last year," the agency said. "Our data also showed that the top 20 anticancer drugs claimed 979.7 billion won, accounting for 51.3 percent of the total anticancer drug claims."

The agency's data also showed that claims for lung cancer and breast cancer treatments were higher than other cancers.

"AstraZeneca's lung cancer treatment Tagrisso accounted for the most claims with 118.5 billion won last year," the agency said. "Since it was registered in Dec. 2017, the drug has continuously increased its claims from 67 billion won in 2018 to 93.7 billion won in 2019 and 118.5 billion won last year."

Other widely used drugs included Roche's Avastin (96.6 billion won), followed by MSD's Keytruda with (79 billion won), Roche's breast cancer drug Perjeta (78 billion) won, and Herceptin (71.2 billion won).

Roche's Tecentriq, which was not on the list until last year, also took ninth place after making claims of 39.2 billion won last year, and Pfizer's breast cancer treatment Ibrance claimed 69.2 billion won, up from 48 billion won last year.