ESTRO 2024 - Abstract Book

S949

Clinical - CNS

ESTRO 2024

: From May 2011 to August 2022 50 patients (pts) were treated, and included in this retrospective analysis (patients and treatments characteristics are shown in Tab.1). A histological secreting pituitary adenoma was diagnosed for 19 pts, while non secreting adenomas were diagnosed in the others. Seven pts were treated with radiotherapy (RT) only due to comorbidities. The median interval from diagnosis to surgery or RT was, 1.0 (0.99-241.49) and 6.2 (1.62 81.26) months respectively; the median time between surgery and RT in pts with residual or relapsed disease was of 86.9 (6.78-297.12) months. Pts were treated with 4 different external beam RT techniques as follows: 1 patient with IMRT, 22 patients with volumetric-arc therapy (VMAT), 21 with helical IMRT (Tomotherapy, TT), and 6 with robotic SRS/stereotactic radiotherapy (CyberKnife,CK). For CK treatments a total dose of 25 Gy in 5 Fractions (fr) was prescribed for 4 patients, 25 Gy in 1 fraction for one patient, and 30 Gy in 5 fractions for another patient. For those treated with other RT techniques, a conventional treatment of 1.8/2 Gy was used to a median total dose of 48.6 Gy (48.0-60.0). The median treatment volumes with the IMRT, VMAT and TT techniques were: Gross Tumor Volume (GTV) 9.74 cc (2.23-56.99), Planning Target Volume (PTV) 28.6 cc (14.5-171.3) with a mean dose to the chiasm of 46.7 Gy. The median GTV and PTV with CK technique was 8.52cc (0.42-9.08) and 10.63cc (1.28-11.97), respectively, with an average dose to the chiasm of 13.1 Gy (3.1-19.4). Follow-up visits were scheduled every six months in the first two years, than once a year. Pts were re-evaluated with brain MRI, computerized visual campimetry, and blood tests for the evaluation of pituitary hormones according to the endocrinologists’ prescription.

Results:

Median follow-up was 33 (0-122.8) months. No G3 or higher toxicities were found. One patient died for other causes (sepsis), and 5 pts were followed at other centers, thus 44 pts were evaluable for late toxicity and efficacy results. Only three (6.8%) patients presented progressive disease, two of them already at the first MRI evaluation. Only one patient (2.3%) died for disease progression 57 months after the end of RT, and four (9.1%) suffered a worsening of vision, with a mean interval of 39.2 (28.8-49.0) months. Hormonal control was obtained in 94.7%, and only 1/19 patients had an uncontrolled hormonal status (Secreting PRL adenoma) at the end of follow-up. Tree-year overall survival (OS) was 88.5% and 5-year OS was 82.6%. (See Fig. 1).