Results of Stereotactic Radiotherapy Using The CyberKnife-M6 For Patients With Pituitary Tumors Running Head: Radiotherapy For Pituitary Tumors

Background This study aimed to evaluate the efficacy of hypofractionated stereotactic radiotherapy (hSRT) using the CyberKnife-M6 (CK-M6) system in patients with pituitary tumors. Methods Between 2020 and 2024, 27 patients were treated. Follow-up evaluations were conducted at 3 months, 9 months, and annually after treatment. Results The median follow-up duration was 22 months (10–58), and the median age was 51 years (32–78). The median interval between surgery and hSRT was 45 months (3- 214). The median planning target volume was 5.23 cc (0.15–30.42). Patients received a median dose of 23 Gy (18–25) over 3 to 5 fractions. The median biologically effective dose (BED ₂ ) value was 81.6 (60- 94.5). The median beam-on time was 16 minutes (12–22). Visual function was preserved in 96% of the cases, while new-onset hypopituitarism was observed in 11%. At the last follow-up, radiologically objective response, stable disease, and progression rates were 30%, 63%, and 7%, respectively. Hormonal response was achieved in 67% (4 out of 6) of functioning adenomas, with a median time of 22 months (3–39). The two-year rates for local control, overall survival, and progression-free survival were 96,3%, 91,2%, and 90,8%, respectively. Conclusions CK-M6-based hSRT offers a precise treatment option for patients with pituitary adenoma, with 96% local control, and the added benefit of a shorter treatment duration.