Medicine should help a patient, not to promote a disease. This is a must. Otherwise, why we should take this medicine? But it might not be the case if we are talking about cancer chemotherapy.
While trying to figure out why cancer cells are very sensitive to chemotherapy in the lab but so resistant to it in the human body, scientists came to a shocking conclusion:  chemotherapy drugs make healthy cells produce a substance called WNT16B, which not only promotes cancer cells? growth but also makes them resistant to chemotherapy.
This explains a fact that every oncologist knows:  initial response to chemo is good but then the tumor becomes resistant to treatment and starts growing uncontrollably. Now it is clear why — because of chemotherapy-induced WNT16B production.  
So it appears that chemotherapy side effects might actually promote cancer. Not a comforting thought. And it?s unlikely that there will be a cancer cure from chemotherapy in the near future. It?s simply not the miracle drug that everyone had hoped for.
Better than chemo
Prevention should be the goal in regard to cancer. In my opinion, risk reduction is the best approach.
Risk factors are very well known:  
Obesity
Smoking
Alcohol
In addition to controlling those factors, there are other steps I recommend taking:
Get optimal vitamin D level in your body.
Get enough sleep. Go to sleep at sundown and get up at sunrise.
Stick to a Paleolithic diet provided that your digestive system is healthy.
Stay away from toxins.
Exercise at least 3 times a week, but do it naturally:  do your chores rather than run on a treadmill.
Stick with wild mercury-free fish and grass-fed organic meats and poultry instead of eating farm-raised fish and meats.
Good luck!
 
References:
http://www.nature.com/nm/journal/vaop/ncurrent/full/nm.2890.html