Are yearly checkup's vital for cancer prevention? will there be, in the near future, blood tests to detect cancer?

Annual physical examination is only necessary for skin cancer screening and cervical cancer prevention by vaccination for HPV and colon cancer by colonoscopy and polyp removal. For reducing the risk of other cancer, you can get testing for H. Pylori for stomach cancer, PSA for prostate cancer. Most of cancer risk can be reduced by healthy lifestyle, and diagnosed early by annuals. Hope it helps.

Depends on many things. At your age with no history of any cancer in the family there is no need for a cancer check up yearly. Medical science is advancing at a phenomenal rate so there just might be such test in the future. Don't worry and enjoy life