The remarkable appeal of dissolvable microneedle-based patch has captivated both the academic community and pharmaceutical industry due to their immense potential as an innovative solution for tumor detection and treatment. Designed to dissolve under physiological conditions, the microneedles release therapeutic agents or diagnostic compounds precisely at the target site, reducing systemic side effects and enhancing therapeutic outcomes. This chapter provides an overview of biomedical microneedles for tumor detection, emphasizing their role in minimally invasive diagnostics and early cancer identification. Then explores the design principles and strategies behind dissolvable microneedles for therapeutic potential, highlighting their use in targeted drug delivery for chemotherapy, biologic therapy, phototherapy, and combination treatments. The integration of this technology with emerging drug formulations, material science, and biosensing capabilities positions microneedle-based patches as a next-generation tool in personalized cancer care.