Research is still evolving, but evidence continues to point to a link between smoking and breast cancer risk. From firsthand and secondhand smoke to vaping and cannabis, here's what scientists knowand what E cigarettes: 'cancer risk close to zero' Bhekisisa Cigarettes or vapes, pick your poison Fred Hutch Vaping may raise cancer and heart disease risk, study suggests Medical research The Guardian Breast Cancer & E Cigarettes: Is Vaping a Safer Alternative to Smoking? Maurer Foundation Research shows vaping is far less harmful than smoking