More tests, not always best:

ASCO's Top Five list for oncology

Chemotherapy for patients with advanced cancers who have seen little or no benefit from prior treatment.
PET, CT and radionuclide bone scans in low-risk prostate cancer patients.
PET, CT and radionuclide bone scans in low-risk breast cancer patients
Surveillance testing and imaging for breast cancer survivors with no symptoms
White cell-stimulating factors for primary prevention of fever/infection associated with neutropenia (a low number of a type of white blood cells) in low-risk patients