Not saying as a sexual aid, but my thought was that there is a tremendous increase in pot use. And today’s grass is not your daddy’s weed. With legal marijuana, use is through the roof. It has been shown that smoking increases the risk of colon cancer dramatically, and the long term effects of Marijuana use is still not understood. As a former heavy smoker and colon cancer survivor (so far), I am aware of the risk. So you ask yourself, what has changed more than anything else in the last decade? I think two that stand out are the vaccine and mj. However, I have absolutely no facts to support my theory.
I lean more to suspecting some unspecified food additive. It doesn’t have to be just in the last decade as a pre-cancerous condition could develop over many years previous. Or an industrial effluent in the atmosphere, etc. If the trend could be narrowed down to a given geographic area the latter possibility would be more likely.