Hi im akshaya.My father is diagnosed with colon cancer .He is 54 years.He has undergone open surgery yesterday.After the surgery the doctors said the tissues were very strng ,matured maybe grown for a longer time.Although the surgery is over they said they cant assure whether all the cells are removed.They prefer a chemotherapy .they said its the 3rd stage.but it does not spread to other places.is that true that lifespan decreases after chemo.plz explain.thanks