Many, like most lung cancers, some colon cancers, most cervical cancers, most skin cancers. Many are not. I'm a 3 time cancer survivor and none could have been prevented. Cancer cells travel through our body a lot and our immune system and T-cells take care of it. Sometimes there is a weakness and cancer forms. Some cancers, like breast, can be genetic. I can't give a figure, just a few things I've learned along life's way.
According to dr oz we all have(the potential for cancer) cancer the only thing is what do we take into our bodies that will eventually trigger it to mutate/grow. So technically we could stop all cancer if we could eat the perfect foods and not go around anything that will trigger the onset of the first cells to mutate.so the point is you could go your whole life without triggering the cancer to grow or you could eat a sandwich or breath a car exhaust one day and it could maybe possibly cause the cell to mutate without you doing anything wrong while eating the perfect foods/all the best healthiest foods.but after we get this cell triggered the only hope is for early detection to begin treatment before it has a chance to take off.so i would say if it is caught early enough all cancer can be treated/prevented/stopped from advancing into a tumor/encroaching on other organs..
Many of the lung cancers could be prevented by people smoking less. Lower cancer rates are possible by eliminating or limiting exposure to carcinogens. Many cancers could be prevented in this way. I think many cancers are hereditary. I know one family where two sisters died of cancer at around the age thirty. Also both these women had a child die at around the age of thirty of cancer. Here you have four people with very similar genetic codes dieing of the same type of cancer between the age of 30 to 33. I can think of a few more similar examples.
Around 45 Percent A Lot Of That Has To Do With What You Do Or Eat.. Like Not Smoking.. Or Not Going Out In The Sun Without Sunscreen.. Some Is Genetic I Think.. Like Breast..
Probably most of them, depending on the preventive maintenance involved.
33.33% of it are preventable
About 33% of cancers are preventable