"I have no bad habits, why did I get it?"
A research paper published in January 2015 in a reputed journal called Science made a lot of eyebrows raise! The media across the globe quoted this paper to call cancer only to be a matter of ‘bad luck’ in a way conveying that what one does (lifestyle) just does not matter.
The paper in concern was designed to understand why some tissues in the body were more prone to cancer (e.g. colon) compared to other (e.g. brain). The final interpretation of the study was that the chance of developing cancer depended on the rate at which those cells multiplied normally. For example, the cells in colon need to multiply at a very high rate when compared to brain cells, which may hardly ever multiply. This makes colon cancer much more common.
This study was not based on population study, but, based on cells in tissue culture in laboratories. They compared about 31 research papers to conclude that occurrence of cancer is more common in cells that are multiplying at high rate, just as a matter of luck. These mutations (error in copying of DNA), if not corrected by body, could lead to cancer. Error in copying does occur every day, however, they are corrected immediately. But in cells that are multiplying very fast, these changes may be missed in haste and lead to cancer formation. And this is just a matter of luck.
All the lifestyle factors like smoking, alcohol, etc. contribute to cancer causation by increasing the multiplication of cells. It is proven beyond reasonable doubt that the environmental factors have a great role to play in causing cancer. The elements that increase rate of cell multiplication in various tissues include environmental factors (pollution, tobacco, etc.) or infections (hepatitis) or others. Anything that increases the rate of cell multiplication can cause cancer. However, cancer can occur in the absence of these stimuli as well and in those cases it is due to bad luck. These are mainly due to errors in DNA copying. For this reason, the strategies of cancer prevention still hold good. Though they fail to prevent or detect all cancers, they would pickup a significant number of them. However, in the absence of these causative factors sheer bad luck leading to copying error which goes uncorrected can cause to cancer.