How to detect Cancer at an Early stage

According to what i have read at yahoo there are tips on how to detect cancer on its early stage:

1. Skin - check your skin, sometimes Skin cancer appears in moles of your skin. If you 
can see some irregularities on your mole such as the shape, color have it 
checked by a doctor
2. Check your stools - Early signs of Colon cancer is the presence of blood on your
stool. Irregularities on your bowel movement, and noticably 
reduction of the thickness of your stool.
3. Mouth - Oral cancer appears as mouth sores that does not heal.
4. Testicles - Testicular cancer can be detect by checking for unusual lumps on your
testicles followed by sudden tenderness, pain, swelling and unnatural 
heaviness in the testicles