Radio-frequency (RF) mild hyperthermia effect sensitized by biodegradable nanoparticles are promising approach for therapy and diagnostics of numerous human diseases including cancer. We report on the effect of biodegradation of low-toxic porous silicon nanowires (PSi NWs) on the enhancement of local hypothermic destruction of cancer cells when exposed to a RF field. Proper selection of RF irradiation time (10 min), intensity, concentration of PSi NWs and incubation time (24 hours), allowed cell viability suppression between five and eight times, which can be potentially used for anti-cancer treatment. High biodegradability of the nanowires are determined by their fine nanoporous structure with average size of pores about of 10 nm and size of silicon nanocrystals (quantum dots) of 3-5 nm. Degradation of PSi NWs in water and phosphate-buffered saline (PBS) during incubation at 37 oC led to decrease of average nanocrystal diameter. We observe that the degradation rate of PSi NWs was essential in PBS due to higher ionic strength, resulting significant decrease of optical absorbance, photoluminescence and Raman signals of PSi NWs in suspensions after 24 hours of incubation. Another consequence was formation of silicic acid in abundance, which drastically influence the conductivity of PSi NWs and RF hyperthermia effect in model and in vitro experiments. Thus, efficient photoluminescence properties of PSi NWs in combination with their biodegradability, as well as local sensitization of RF-induced hyperthermia effect which lead to cancer cells death, are promising opportunities for their theranostic applications.