In a recently released study by Johns Hopkins, 67% of mutations that cause cancer are random, unpredictable copying mistakes.  Other studies show that 40% of cancers can be prevented based on avoiding unhealthy enviornments or life-style choices.  Cancers initiated by random, unpredictable copying mistakes (or Luck) will occur regardless of the enviornment or life-style choices.

However, the 60/40 split is not common across all cancers.  32 different cancer types were studied.  For example as identified in the study (Johns Hopkins Medicine, 2017):

In other cancer types, such as those of the prostate, brain or bone, more than 95 percent of the mutations are due to random copying errors.

Lung cancer, they note, presents a different picture: 65 percent of all the mutations are due to environmental factors, mostly smoking, and 35 percent are due to DNA copying errors. Inherited factors are not known to play a role in lung cancers.

Looking across all 32 cancer types studied, the researchers estimate that 66 percent of cancer mutations result from copying errors, 29 percent can be attributed to lifestyle or environmental factors, and the remaining 5 percent are inherited.

So luck (good or bad) has a great deal of influence on your health.

Johns Hopkins Medicine. (2017). Most cancer mutations are due to random DNA copying ‘mistakes’. ScienceDaily. Retrieved March 30, 2017 from