PARIS, France - Around 1.5 million lives could be saved every year if the world worked together to more swiftly approve new cancer drugs, researchers said Tuesday.

The figure was based on how long it took two recent cancer drugs to be approved across the world after they were given the green light by the United States.

Pembrolizumab, an effective treatment for most lung cancers, was approved by the US Food and Drug Administration (FDA) in 2016.

More than 600,000 years of patients' lives could have been saved if Brazil, Canada, China, India, Japan and the European Union had approved the drug at the same time, according to an analysis published in the Harvard Business Review, which is not peer-reviewed.

The authors, including US oncologist Bobby Daly, also looked at enzalutamide, which is used to treat prostate cancer.

Enzalutamide was approved by the FDA in 2012, but was not authorised in China for another seven years, partly due to a requirement for separate trials to be carried out there.

The analysis by members of the Bloomberg New Economy International Cancer Coalition found that 284,000 years of patient lives could have been saved if other countries had approved the drug alongside the FDA.

Extrapolating out from their findings, the researchers estimated that if each of the approximately seven cancer drugs approved by the FDA a year were authorised worldwide, it would reduce the number of cancer-related deaths by 10-20 percent.

That represents roughly 1.5 million of the around 10 million people who die of cancer every year.

- 'Challenging' for doctors -

"In China alone an estimated 500,000 patient life-years could be saved through harmonisation of trial requirements that have delayed patient access to treatment," former Australian prime minister Kevin Rudd, co-chair of the Bloomberg cancer coalition, said in a statement.

Mary Gospodarowicz, also a member of the coalition, said that it was "challenging" as an oncologist in Canada when a drug was approved in the US but would take years to be able to prescribe it to her patients.

The study assumed that the rest of the world had the infrastructure to diagnose and treat cancer as well as the US, which is not always the case, Gospodarowicz told AFP via phone from the World Cancer Congress in Geneva on Tuesday.

But it served as an example of how "removing the barriers to drug approval would be beneficial to patients around the world," said the former president of the Union for International Cancer Control, which is holding the congress.

The authors of the analysis called on countries to embrace Project Orbis, a US-led framework aiming to get cancer drugs trialled and approved at the same time in multiple countries.

"The US has already made significant progress in setting up the regulatory infrastructure for cancer treatment with the Project Orbis initiative and the task ahead is to take that framework and internationalise it," former New York mayor Michael Bloomberg said in a statement.