New cancer drugs cost the UK the lowest on average compared with other high-income nations, according to a new study.
The research, published in The Lancet Oncology journal, showed the UK, along with Greece, Spain and Portugal, paid the least per unit for new drugs under patent, while Germany, Switzerland and Sweden paid the most.
Experts called for "far more transparency" in drug pricing, citing fears some nations risked "overpaying" for treatments.
Total healthcare spending on cancer in the European Union was 51 billion euros (£37 billion), a third of which went on drugs, according to the report.
Researchers analysed the June 2013 prices of 31 drugs and compared them across 18 countries, also including Australia and New Zealand.
They found that costs for the countries varied from between 28% and 388% of official prices, while seven of the drugs had a unit price of higher than 1,000 euros (£723), including one for lymphoma and myeloma patients that cost more than 5,000 euros (£3,612) per injection.
In one example, taxpayers in Germany were paying 223% more for a drug to treat melanoma and leukaemia than those in Greece.
Dr Sabine Vogler, from the World Health Organisation's Collaborating Centre for Pharmaceutical Pricing and Reimbursement Policies (WHO PPRI) in Vienna, Austria, said: "Some high-income countries have managed to barter the manufacturers down to lower prices, but these agreements, including the agreed prices, are confidential.
"Although these agreements ensure patient access to new drugs, other countries risk overpaying when setting drug prices through the common practice of external price referencing, or international price comparison, because they can only use the official undiscounted prices as a benchmark.
"There needs to be far more transparency.
"We hope that our findings will provide concrete evidence for policymakers to take action to address high prices and ensure more transparency in cancer drug pricing so that costs and access to new drugs does no depend on where a patient lives."
A group of experts led by Wim van Harten from the Netherlands Cancer Institute also analysed actual drug prices in July this year, and found hospitals are paying prices which differ by up to 58% between countries.
Commenting on the study, he said: "This calls for joint action by countries and medical societies with the pharmaceutical industry, since fast and equitable access to promising new drugs is important to improving treatment results.
"The societal challenge is to combine the development and availability of promising new drugs with the sustainability of our system. All parties involved must agree innovative and sustainable business models to ensure fast access to relevant drugs for patients with cancer."