Re: Blood test for cancer?
The answer is yes and no.
There are some blood tests for indicators for certain types of cancer. For example, the CA 125, if elevated, can be indicative of breast or ovarian cancer. The PSA (prostate specific antigen) test can be indicative of prostate cancer. There are problems, however, in using these tests as a diagnostic tool. The PSA, for example, can be elevated simply from benign prostatitis or enlargement of the prostate, which is not uncommon as men age. And the CA 125 can be normal or close to normal even in advanced stages of cancer (although this isn't common, but it can happen.)
The routine blood work that most people have done once a year, such as a CBC and chem profile, can somtimes give clues. For example, in certain types of cancers, the body's calcium levels become elevated, so an unusually high calcium level on a routine test could alert the doctor that more tests may be needed.
But, unfortunately, cancer is not just one illness, but rather a huge variety of illnesses. Each and every type of cell in the body can become cancerous, but each and every type of cell is unique in terms of how it functions and why it might become cancerous. Examples: Squamous cells are present in the skin and the linings of certain organs, but not in all organs. Small cells are present in the lungs and the linings of the bladder and colon. Breast cells are specific to the breast tissue, endometrial cells are specific to endometrial tissue, etc., etc.
For all those reasons, it is nearly impossible to develop one single test that can determine if cancer is or is not present.