Cancers form when toxins damage or mutate a cell’s DNA and cause it to grow out of control. A tumor can remain local, or the cancer can spread, and even move from one organ to another.
Most people are familiar with cigarette smoking as a cause of lung cancer. Lung cancer kills more Americans than any kind of cancer, and most (but not all) lung cancer victims are smokers. It is a particularly brutal form of cancer.
However, smoking can cause many other kinds of cancer too, because cancers can form not just in areas that have contact with the smoke, but also from smoke byproducts in the bloodstream and organs. According to the Centers for Disease Control and Prevention (CDC), smoking can cause cancer almost anywhere in the body.
Some of the cancers that can be caused by smoking are:
- Blood (leukemia)
- Colon and rectum
- Esophagus and trachea
- Kidney and renal pelvis
- Mouth and throat
Nicotine itself — either in cigarettes or e-cigs, or other nicotine products — has not been shown to cause cancer. Long-term studies of nicotine replacement therapy (NRT) and Swedish snus users show no provable link between nicotine and cancer.
The 2016 Royal College of Physicians (RCP) report “Nicotine Without Smoke” says that “robust evidence on the safety of long-term nicotine use in humans from the 5-year Lung Health Study, in which participants were actively encouraged to use NRT for several months and many continued to consume NRT for a much longer period, demonstrates no association between sustained NRT use and the occurrence of cancer (lung, gastrointestinal or any cancer) or cardiovascular disease.”
Cancers from smoking are caused by the combustion of tobacco. The smoke forms a sticky chemical slurry called tar, and the tar coats delicate parts of the lungs. Over the course of years, the damage created by tar in the lungs can lead to tumor growth. According to the National Cancer Institute (NCI), most of the cancer-causing substances in cigarette smoke is in the tar. Tar also causes damage that can lead to lung diseases like emphysema and bronchitis.
E-cigarettes don’t produce tar, because they don’t burn (or even contain) tobacco or other plant material. There are known carcinogens in vapor, but they’re in tiny concentrations that are unlikely to pose any risk to vapers. Most studies that have raised alarms about cancer risk from vaping have used poor methods, including using smoking machines to take too-frequent or too-long drags, or vaping at unrealistic high temperatures on dry wicks. Those things wouldn’t happen to actual vapers, because the result — known as dry hits or dry puffs — is unbearable to breathe.
“In normal conditions of use, toxin levels in inhaled e-cigarette vapour are probably well below prescribed threshold limit values for occupational exposure, in which case significant long-term harm is unlikely,” says the RCP report. “Some harm from sustained exposure to low levels of toxins over many years may yet emerge, but the magnitude of these risks relative to those of sustained tobacco smoking is likely to be small.”
A recent study at the University of St. Andrews in Scotland found that the cancer danger of vaping is almost as low as for nicotine replacement therapies like patches and gum — less than one percent. “This study should put to rest any doubt within the tobacco control movement about whether vaping greatly reduces health risk compared to smoking,” wrote Boston University’s Dr. Michael Siegel.