ESTRO 2024 - Abstract Book

S963

Clinical - CNS

ESTRO 2024

Fifty cases of pituitary adenomas treated in our centre between 2010 and 2015 were analysed. This period of study was chosen to ensure a proper follow-up.

The mean age at diagnosis was 51 years (28-79 years). Male/female: 21/29. Twenty-six patients (52%) had secretory adenoma (GH: 15; ACTH: 3; TSH: 1; prolactinomas: 3; other: 4). Twenty-four patients presented non-functioning adenomas. FSRT technique: a planning CT fussed with brain MRI was used for contouring target volumes. CTV comprises whole pituitary or residual tumour, and PTV was generated by adding 2-3 mm to the CTV. Patients were treated in stereotactic conditions to a total dose of 50.4 Gy at 1.8 Gy/fraction in Novalis linear accelerator.

Local relapse was defined as disease progression in brain MRI. Hypopituitarism was considered if the hormone level dropped below the inferior limit of normality of each laboratory.

All patients were evaluated with brain MRI, as well as periodical hormonal determinations and ophthalmologic examination, every 4-6 months.

Statistics: Student T, Kaplan-Meier.

Results:

The median of follow- up was 107 months (11-158 months). In the whole group of adenomas (secretory and non functional) the following hormones showed statistically significant decrease when compared pre and post radiotherapy levels: THS (p=0.029), IGF-1 (P=0.000), ACTH (p=0.001), cortisol (p=0.000) and LH (p=0.000).

Results of biochemical control of secretory adenomas are shown in Table 1.

Regarding GH-producing pituitary adenomas, a statistically significant reduction in IGF-1 levels was observed (p= 0.000), as well as in GH levels, although the reduction in GH levels was not statistically significant (p=0.229). This may suggest that IGF-1 is a better marker to assess response in this type of tumour. For ACTH- producing adenoma a reduction in ACTH levels was observed, with non- significance trend (p=0.052). Similarly in prolactinomas, a decrease in prolactin levels was observed although not statistically significant (p=0.416).

Related to TSH-producing adenoma, there were no differences in TSH secretion, because only one patient data was available.

Only one patient (7%) with GH producing adenoma presented persistent hypersecretion after radiotherapy. The rest of the secretory group did not present hypersecretion after radiotherapy and the rest of the treatments undergone previously.

The local control rate was 98%. Five-years overall survival and progression-free survival were 98% and 96% respectively.

Regarding the hormonal deficiencies after radiotherapy where 36% for the GH axis, 36% for the TSH axis, 20% for the adrenal axis and 36% for sexual hormones. Panhypopituitarism, defined as hormone deficiency of the four axes, was not seen during the follow-up.