Cancer patients in the United States may envy the low prices that people in, say, India pay for chemotherapy and other cancer drugs. But in fact, prices are less affordable in low- and middle-income countries, new research shows.

And just as poorer countries’ inability to afford HIV/AIDS drugs ignited bitter controversy, the price of cancer drugs “also raises ethical questions,” said Dr. Daniel Goldstein, who presented the findings at the annual meeting of the American Society of Clinical Oncology in Chicago on Monday.

“If there are effective cancer therapies available in the West and not in developing countries, it will become a serious issue in coming years,” said Goldstein, an oncologist at Israel’s Rabin Medical Center.

Goldstein and his colleagues from four countries calculated the prices of a month’s supply of 23 cancer drugs in Australia, China, India, Israel, South Africa, Great Britain, and the United States.

The median price for eight branded cancer drugs such as Avastin and Gleevec ranged from $1,515 in India to $8,694 in the US, the researchers reported. For 15 generics such as docetaxel and paclitaxel, the cost of a month’s supply ranged from $120 in South Africa to $654 in the US.

But US patients were better able to afford the drugs, when “affordability” is calculated as a percentage of per capita gross domestic product required to pay for a month’s supply of the median-priced drug, the study found.

Per capita GDP can roughly be thought of as each person’s “share” of a country’s total economic output. By that measure, cancer patients in Australia pay 71 percent of their monthly economic output for a month’s supply of a brand-name cancer drug; it’s 313 percent in India, 286 percent in China, and 192 percent in the US.

“The trend we’re seeing is that even though drug prices in India and China are much less than in the US, because their GDP is so much lower, the drugs are significantly less affordable,” Goldstein said.

For generics, affordability ranged from 6 percent of monthly per capita GDP in Australia to 8 percent in Israel to 33 percent in India to 48 percent in China.

Many of the countries in the survey have single-payer, government-run health care systems, so those drug costs are coming out of the national treasury, at least in part, as well as from cancer patients who pay some or all of the cost out of pocket.

Yet, the sticker prices studied by Goldstein’s team might not perfectly track drug expenditures, because the calculations reflect list prices, not discounted prices. Although drug makers often have discount programs, they are so opaque and difficult to qualify, Goldstein cautioned, that it’s almost impossible to learn what they are.

“It’s often a secret,” he said.