According to a new government report, the number of cancer survivors in the USA is close to 12 million, in part because of earlier detection, better diagnoses and more effective treatments. Here's a look at advancements for three cancers:BreastResearchers in Seattle found that women with the highest body mass index had a 35 percent increased risk of a particularly aggressive form of breast cancer compared with those with the lowest. That's a risk factor you can control.LungIt's difficult to diagnose in its most treatable stages, which makes it one of the deadliest cancers. But a study in the journal Lung …