Breast cancer is one of the leading causes of death throughout the world. Early detection of breast cancer can prevent the death of many women throughout the world. There are many methods to detect tumor in breast tissue samples. Plasmonic-based sensors are of great importance in recent optical technology. A perfect semiconductor metamaterial absorber based on surface plasmon resonance is designed, and its sensing capability to detect breast cancer is investigated using numerical simulations. The indium antimonide (InSb) is used as an optimized semiconductor in the structure and the absorption value of 99.22% is obtained. The thermal, material, optical, and geometrical tunability of the structure is investigated. The maximum refractive index sensitivity as high as 24,680 nm/RIU is obtained. Moreover, it is shown that the structure can effectively work as a breast cancer detector. Furthermore, the temperature sensitivity of the structure is also analyzed, and the ultra-high value of 10,830 nm/K is obtained for thermo-optical sensitivity of this design/device.