WASHINGTON — Curbing tobacco use and taking other steps to eliminate some of the most common risk factors for cancer could save millions of lives over the next few decades, health officials said Monday. Tobacco alone is predicted to kill a billion people this century, 10 times the toll it took in the 20th century, if current trends hold. ‘In all of world history, this is the largest train wreck not waiting to happen,’ said John Seffrin, chief executive officer of the American Cancer Society. Reducing tobacco use would have the single largest effect on global cancer rates, Seffrin and other health officials said Monday in unveiling two reference guides that chart global tobacco use and cancer. Changing diets to contain fewer saturated fats and more fruits and vegetables, as well as reducing infection by cancer-causing viruses and bacteria, could also cut rates dramatically, they said. ‘We know with cancer, if we take action now, we can save 2 million lives a year by 2020 and 6.5 million by 2040,’ said Dr. Judith Mackay, a World Health Organization senior policy adviser. Today, tobacco accounts for one in five cancer deaths, or 1.4 million deaths […]