Stereotactic Radiotherapy for Pituitary Adenomas

Objectives: : Among the recent advances in the field of radiotherapy for the treatment of pituitary adenomas, stereotaxy has emerged as a highly precise and effective method. This technique allows for the delivery of a high dose of targeted radiation to the tumor while minimizing exposure to surrounding healthy tissues, thus providing a non-invasive therapeutic option, particularly for recurrent or residual tumors after surgery. The use of fractionated stereotactic radiotherapy or single-dose radiotherapy (radiosurgery) is particularly indicated for adenomas that are difficult to treat surgically, reducing the risks of complications and tumor recurrence.

Methods: : In our study, we present the cases of six patients treated for pituitary adenomas and currently under post-therapeutic follow-up at Chahid Mahmoudi Hospital in Algeria , in the radiotherapy department using the stereotactic technique. The first case was treated in 2019 with a fraction of 15 Gy, and the other cases between 2023 and 2024 according to protocols of 25 Gy in 5 fractions and 21 Gy in 3 fractions. The fusion of CT images with MRI allowed for the delineation of the treatment volume as well as the organs at risk.
A treatment plan was developed using the Eclipse Treatment Planning System and calculated with the Acuros XB version 13.7 calculation algorithm, following the published dosimetric recommendations for stereotactic irradiation. A quality control of the treatment plan was performed using portal imaging on the Clinac IX 23 treatment machine from Varian, and a validation was conducted with the radiation oncologist. During each treatment session, positioning imaging was performed with the Exatract system to ensure the accuracy of the patient's positioning.

Results: : In our poster, we will present the dosimetric results obtained as well as the post-therapeutic follow-up results observed, showing a stability of the tumor volume noted during the 6-month and 1-year MRI controls. For hormonal assessments, initially characterized by disturbances, stabilization was observed after radiotherapy treatment, with normalization of parameters and a decrease in parotid volume.

Conclusion(s):: Stereotactic radiotherapy has proven to be a highly precise and effective treatment option for pituitary adenomas, especially in cases where surgery is not feasible or when dealing with recurrent or residual tumors. The method’s ability to deliver high doses of radiation while sparing surrounding healthy tissues minimizes complications and tumor recurrence. The results from our study demonstrate that this technique offers favorable outcomes, including stabilization of tumor volume and hormonal balance, thus providing a safe, non-invasive alternative to conventional surgery.