Determining the effectiveness of hormone therapy in cancer involves a multi-faceted approach, combining diagnostic imaging and specific laboratory tests to monitor tumor response and disease progression. For prostate cancer, routine blood tests measure prostate-specific antigen (PSA) levels, a key biomarker indicating disease activity and response to hormone-modulating therapies. Prostate MRI may also be used in some cases to track tumor changes. For breast cancer, monitoring involves diagnostic imaging such as mammograms, breast ultrasounds, and, when necessary, breast MRIs. Laboratory tests, including those for specific tumor markers or hormone levels, are also conducted. For both cancer types, a rise in relevant biomarker levels (e.g., PSA) or continued tumor growth during treatment signifies to specialist physicians that the hormone therapy is not effective and may need adjustment.