A clinical study of Cyberknife treatment for oral squamous cell carcinoma

Abstract

Cyberknife (CK) is one of the treatment options for oral squamous cell carcinoma. However, there are few reports regarding treatment with CK in Japan, and standard criteria defining indications have not been established. We often perform radiation therapy with CK in patients who cannot undergo standard therapy because of extremely advanced disease, high-risk general conditions, refusal of surgery, or other reasons. We retrospectively assessed 32 patients treated from 2006 to 2017 and evaluated the clinical significance. Within 4 months after CK treatment, the response rate was 72%. The overall survival rates at 2 years and 5 years were 42% and 15%, respectively, and the median survival was 23 months. Clinical factors for CK treatment outcomes were explored. The results showed that primary tumor size (T classification), stage, irradiation timing, and planning target volume (PTV) were statistically significant factors. Tumors with a small diameter at the time of primary onset could be controlled similar to surgery in terms of the 3-year survival rate. This study suggested that CK treatment might be an effective treatment for tumor suppression in patients in whom no other treatment was indicated.