<p style="text-align:justify"><span style="font-size:11pt"><strong><span style="font-size:10.0pt">Background:</span></strong><span style="font-size:10.0pt"> This study examines the synergistic impact of Gold-Gold Sulfide (GGS) nanoparticles combined with hyperthermia and radiotherapy on MCF-7 cancer cells. GGS nanoparticles, with strong near-infrared absorption and photothermal properties, enhance cellular sensitivity to radiotherapy. </span></span></p> <p style="text-align:justify"><span style="font-size:11pt"><strong><span style="font-size:10.0pt">Methods:</span></strong><span style="font-size:10.0pt"> MCF-7 cells were treated with varying GGS concentrations and exposed to radiation doses of 50, 100, and 200 <em>cGy</em>, alongside laser irradiation for 10, 40, and 80 <em>s</em>. The IC₅₀ for GGS nanoparticles was approximately 350 <em>&micro;M</em>. </span></span></p> <p style="text-align:justify"><span style="font-size:11pt"><strong><span style="font-size:10.0pt">Results:</span></strong><span style="font-size:10.0pt"> Results revealed a significant reduction in cell viability with the combined GGS and laser exposure (p&lt;0.001), demonstrating a synergistic effect in a dose-dependent manner. Further enhancement in cell viability reduction was observed when GGS nanoparticles were combined with both hyperthermia and radiotherapy (p&lt;0.01). </span></span></p> <p style="text-align:justify"><span style="font-size:11pt"><strong><span style="font-size:10.0pt">Conclusion:</span></strong><span style="font-size:10.0pt"> These findings suggest that GGS nanoparticles offer greater efficacy and reduced toxicity compared to gold nanoparticles, highlighting their potential for improving cancer therapy outcomes through combined hyperthermic and radiotherapeutic approaches.</span></span></p>