Follow the acronym C.A.U.T.I.O.N.
C: Change in Bowel or Bladder habits
A: A sore or blemish that doesn't heal
U: Unusual Bleeding or fluid discharge
T: Thickening/Lump on your body, especially the genitals and breasts (men too)
I: Indigestion and/or difficulty in swallowing
O: Obvious change in blemish, mole, and or wart
N: Nagging cough or hoarseness in throat
If you see any of these signs, see a doctor. Do not put it off, it will only make things worse in the long run.