Depends on the cancer and even the doctors are torn. Most breast tumors and prostate tumors will not kill you or affect your life much. Treating them likely will (especially for prostate). Depending on the model, the overall health of the population is actually reduced by early detection because in most of these tumors treatment is worse than the disease.
One of my doctors is a strong believer in periodic prostate exams after 40. The other recommends only if there are other symptoms. You can guess which is the older one and which is the younger one.
Years ago there was the whole Gardasil controversy. What was often excluded in the noise was that if it were mandated for all girls as some states were recommending, it would be so expensive that funding for other health programs would need to be reduced. The studies were showing that this kind of preventative approach would again reduce the health of the state's population.
Preventive medicine is good - to an extent. Beyond that it is bad.