Dx breast cancer at 39, thyroid cancer at 40. is a pet scan needed to rule out mets and am i at a risk for other cancers?

Cancer: Excellent question. It all depends on what type is cancer. If your breast cancer is localized and resectable, unlikely you need a metastatic work up with PET. If you have well differentiated thyroid cancer, you may also not need PET. However, your oncologist may get a baseline scan. You may have a genetic predisposition and may need screening for colon, cervical and ovarian ca.

Possibly: Hereditary predisposition to certain cancers usually occur at earlier ages. At age of less than 50 yrs you would qualify for genetic testing for BRCA 1 & 2 mutations. A PET scan depending on the clinical situation can detect spread of disease (not as good in the brain) to other organs but in someone with BRCA gene mutation, the development of other kinds of cancer may not occur at the same time.

Genetic testing: You definitely need genetic counseling and testing. A complete family history will help direct this as well. There is no role for screening to look for metastatic disease if you are not known to have it.

PET scan: Interesting question. I would first pursue genetic counseling. PET is not used for routine thyroid cancer surveillance unless the cancer has lost its ability to take up iodine. I get many referrals of breast cancer patients who got PET from their breast doctor and they have thyroid lesions that require evaluation. Don't jump to PET. It's easy to do, but expensive, and most helpful when it is neg.