A Case of Chemoradiotherapy with Interstitial Brachytherapy for the Definitive Treatment of Early-Stage Vaginal Carcinosarcoma in a Young Adult Patient: Achieving Disease Control while Maintaining Sexual Function and Quality of Life.

Introduction: Primary vaginal carcinosarcoma is extremely rare, with only 12 cases reported to date. A consensus has not been reached on the best treatment approach as most patients undergo surgery; however, the disease is highly refractory. Case Presentation: We present the case of a 34-year-old woman diagnosed with vaginal carcinosarcoma after experiencing vaginal pain and bleeding. She opted for organ preservation and underwent definitive chemoradiotherapy (dCRT) using interstitial brachytherapy, receiving an initial concurrent chemoradiotherapy dose of 50 Gy in 25 fractions with weekly cisplatin. This treatment was followed by brachytherapy, in which 22.5 Gy was delivered in three fractions. To prevent vaginal stenosis, the patient was advised to undergo regular vaginal irrigation and to engage in sexual activity. At 25 months after treatment, the patient remained disease-free. The patient reported minimal impact on sexual activity, and her quality of life (QoL) was well maintained. Conclusion: To our knowledge, this is the first reported case of early-stage vaginal carcinosarcoma treated with dCRT. This suggests a promising treatment option for preserving organs. The prevention of vaginal stenosis following dCRT, in addition to organ conservation, is essential for preserving sexual function and QoL.