The theranostic probe DMTP-1 specifically targets monoamine oxidase A (MAO-A), an enzyme upregulated in senescent tumor cells, converting to the active compound ADMTP-1 that both fluoresces for imaging and generates reactive oxygen species for photodynamic therapy. Testing demonstrated markedly enhanced fluorescence signals and photodynamic efficacy in MAO-A-overexpressing senescent cells, with successful visualization in zebrafish models and activity in 3D tumor spheroids. This represents a significant advance in cancer treatment strategy, addressing a critical gap in oncology. Senescent cancer cells often survive initial therapies and create inflammatory microenvironments that promote tumor recurrence and metastasis. Current senolytic approaches lack the precision needed for clinical translation, relying on biomarkers like SA-β-gal with limited specificity. DMTP-1's dual functionality—simultaneous detection and elimination—could transform how oncologists manage residual senescent cells post-treatment. However, the approach requires light activation, limiting its application to accessible tumors or those reached through fiber optics. The zebrafish model validation is encouraging, though human translation remains uncertain. If successful clinically, this targeted senolytic strategy could substantially reduce cancer recurrence rates by eliminating the cellular reservoirs that fuel tumor regrowth.