Promising Outcomes in Acromegaly Patients Receiving CyberKnife Stereotactic Hypofractionated Radiotherapy

Rasim Meral; Ozlem S Selcukbiricik; Ayse K Uzum; Serdar Sahin; Murat Okutan; Mehmet Barburoglu; Ilyas Dolas; Musa Altun; Sema Yarman; Pinar Kadıoglu

doi:10.7759/cureus.47936

Promising Outcomes in Acromegaly Patients Receiving CyberKnife Stereotactic Hypofractionated Radiotherapy

Cureus. 2023 Oct 29;15(10):e47936. doi: 10.7759/cureus.47936. eCollection 2023 Oct.

Authors

Rasim Meral^{1

2}, Ozlem S Selcukbiricik³, Ayse K Uzum³, Serdar Sahin⁴, Murat Okutan⁵, Mehmet Barburoglu⁶, Ilyas Dolas⁷, Musa Altun², Sema Yarman³, Pinar Kadıoglu⁴

Affiliations

¹ Department of Clinical Oncology, Istanbul University Institute of Oncology, Istanbul, TUR.
² Department of Radiation Oncology, Istanbul University School of Medicine, Istanbul, TUR.
³ Department of Endocrinology, Istanbul University School of Medicine, Istanbul, TUR.
⁴ Department of Endocrinology, Istanbul University - Cerrahpasa School of Medicine, Istanbul, TUR.
⁵ Department of Medical Physics, Istanbul University Institute of Oncology, Istanbul, TUR.
⁶ Department of Radiology, Istanbul University School of Medicine, Istanbul, TUR.
⁷ Department of Neurological Surgery, Istanbul University School of Medicine, Istanbul, TUR.

Abstract

Background: The primary treatment for patients with acromegaly has traditionally been transsphenoidal surgery, with decreasing reliance on radiotherapy (RT) due to advancements in pharmacotherapy (PT). Despite these advancements, a substantial portion of patients still face persistent acromegaly, necessitating novel treatment approaches. This study investigates the role of CyberKnife Stereotactic Hypofractionated Radiotherapy (CK-HFRT) in persistent acromegaly.

Objective: The primary objective was to assess the impact of CK-HFRT on endocrine remission (ER) rates while maintaining acceptable toxicity levels.

Methods: The study retrospectively analyzed 31 consecutive patients with acromegaly who received CK-HFRT following multiple unsuccessful surgeries and prolonged PT without ER. Various CK-HFRT dose fractionation regimes were administered, and dose volume histograms were evaluated. Tumor control, cured disease (CD), endocrine remission (ER) rates, and overall survival were estimated at a median follow-up of 62 months. Acute and late toxicity, including pituitary insufficiency and radiation-induced optic neuropathy (RION), were also assessed.

Results: At 62 months of follow-up, the study group demonstrated excellent tumor control with 100% nonprogressive adenomas. Endocrine remission was achieved in 86.7% of patients, with a 22.4% CD rate at five years. Pituitary insufficiency occurred in 32.3% of patients, and no cases of RION were reported. The study observed three deaths related to cardiovascular diseases, all in patients receiving PT. Overall survival at five years was 79.2%.

Conclusion: CyberKnife stereotactic hypofractionated radiotherapy, as an adjunct to PT, provides a viable treatment option for patients with persistent acromegaly following unsuccessful surgeries. The therapy results in substantial ER rates and tumor control while minimizing the risk of permanent radiation-induced optic neuropathy. However, the decision to administer CK-HFRT should be individualized, considering the patient's overall condition and treatment history.

Keywords: acromegaly; cyberknife stereotactic hypofractionated radiotherapy; endocrine remission; pituitary adenoma; pituitary insufficiency; radiation induced optic neuropathy.