Five billion people worldwide do not have access to safe surgery and anesthesia, more than double previous estimates, resulting in more deaths than malaria, AIDS and tuberculosis combined, the Lancet Commission on Global Surgery said.
The lack of operations causes a third of all deaths worldwide, with nearly 17 million people dying from conditions needing surgical care in 2010, a report published by the commission on Monday said.
The report was written by 25 leading experts in surgery and anesthesia with contributions from more than 110 countries.
"In the absence of surgical care, common, easily treatable illnesses become fatal," said Andy Leather, a lead author of the report.
"The global community cannot continue to ignore this problem – millions of people are already dying unnecessarily, and the need ... is projected to increase in the coming decades," said Leather, who is director of the King's Centre for Global Health, King's College London.
Many of the worst affected countries face rising rates of cancer, cardiovascular disease and road accidents, he added.
New estimates produced for the commission found that there is a global shortfall of at least 143 million surgical procedures every year, with some regions needing nearly twice as many additional operations as others.
And a quarter of people worldwide who do have an operation face "financial catastrophe" as a result of the costs of seeking care, the authors said.
"Although the scale-up costs are large, the costs of inaction are higher, and will accumulate progressively with delay," said lead author John Meara, Kletjian Professor in Global Surgery at Harvard Medical School, and associate professor of surgery at Boston Children's Hospital.
"There is a pervasive misconception that the costs of providing safe and accessible surgery put it beyond the reach of any but the richest countries.
"But our work for this Commission clearly shows that not only are the costs of providing these essential services lower than might have been thought, but that scale-up of surgical and anesthesia care should be viewed as a highly-cost-effective investment, rather than a cost," Meara added.
The commission, which was established by the Lancet medical journal, carried out research into the cost of scaling up access to surgery in developing countries.
It estimated that $420 billion is needed for the 88 countries where access to surgery is weakest, to scale up to "acceptable" levels by 2030. The countries include China, India and South Africa.
It also estimated that the economies of developing countries will lose an estimated $12.3 trillion between 2015 and 2030 without a major scale-up in investment in surgery.