The only ‘preventive measure’ an adolescent can take include learning which cancers you are more likely to get and paying attention to your body . . most of the time the only warning you will get is an odd lump or bump located anywhere in or on the body. Teens should see a doctor on a yearly basis and make sure to point out anything unusual.

Here are the most common adolescent cancers and the ones any teen should be looking out for:

Leukemia – blood
Lymphoma – lymph nodes
Osteosarcoma – bone
Ewings Sarcoma – bone
Brain Tumor – brain
Soft Tissue sarcoma – tendons, muscles
Germ Cell Tumor (Testicular or Ovarian Cancers)
Malignant Melanoma – skin

Perhaps one day the medical community will begin to educate adolescents and young adults about the types of cancer they are more likely to get. It is fairly unusual for teens to get lung cancer, breast cancer, colon cancer, or prostate cancer . . . but those are the only cancers you ever hear about. Those are diseases, in general, of older people.
References :
Experience. Teen son diagnosed with stage IV abdominal sarcoma.