The number of cancer cases worldwide now stands at 12 million a year - up a fifth in under a decade, according to new figures today. It is more than four times the annual number of new HIV infections, and 2.8 million cases are linked to poor diet, a lack of exercise and being overweight. The number of cancers that could potentially be prevented is expected to rise dramatically over the next decade, as more and more people lead sedentary lifestyles and become obese. The top 10 most common cancers worldwide are lung (1.608,055), breast (1. 384,155), bowel (1.235,108), stomach (988,602), prostate (899,102), cervical (530,232), oesophagus (481,645), liver (479,744), bladder (382,660) and non-Hodgkin\'s lymphoma (356,431). The data was released by the World Cancer Research Fund (WCRF), ahead of the United Nations summit on non-communicable diseases. It is already known that 80,000 cancer cases every year could be prevented in the UK if people kept their diet, weight and alcohol intake in check and took regular exercise. The UK ranks 22nd out of 50 in a global chart of the number of cancer cases per 100,000 people. There are 267 cases per 100,000 in the UK, more than Spain, France, Croatia, Sweden and Finland. Topping the chart is Denmark (326 cases per 100, 000), followed by Ireland, Australia and New Zealand. The US ranks sixth, with 300 cases per 100,000 people. The WCRF said today the UN summit later this month is a \"once-in-a-generation\" chance to avoid a public health disaster. The summit will look at diseases such as cancer, heart disease, diabetes and respiratory disease. The charity says a failure to develop robust global and national policy for preventing non-communicable diseases will lead to millions of preventable deaths. It says Prime Minister David Cameron should attend the summit in person to demonstrate his commitment to tackling disease in the UK and worldwide. Professor Martin Wiseman, medical and scientific adviser for the WCRF, said: \"Cancer and other lifestyle-related diseases are one of the biggest challenges we face today and the UN Summit later this month is a real turning point. \"With millions of lives at risk around the world, the stakes are incredibly high. \"And while this is an issue facing millions globally, every day in the UK people are being diagnosed with a cancer that could have been prevented.\" Already there are seven million cancer cases diagnosed a year in the developing world and that is likely to rise dramatically.