Stereotactic Radiosurgery and Fractionated Stereotactic Radiotherapy With a Linear Accelerator (LINAC) for Acromegaly Remission: Clinical Experience From a Tertiary Neurological Center in Latin America.

Background and objective Fractionated stereotactic radiotherapy (FSRT) and stereotactic radiosurgery (SRS) are commonly used in patients with growth hormone (GH)-secreting pituitary adenomas (PAs) who are not candidates for surgery, have residual disease postoperatively, or have failed or cannot access medical therapy. It is also considered a first-line option in elderly patients or those with comorbidities that contraindicate surgery. In this study, we aimed to evaluate the long-term outcomes of SRS and FSRT in patients with acromegaly who remained biochemically active despite prior surgical and/or medical treatment.  Methods This was an observational, analytical, longitudinal, and retrospective study with an 11-year follow-up. Patients were divided into two groups according to the radiotherapy modality (SRS or FSRT, both delivered via a linear accelerator (LINAC)). Outcome measures included biochemical remission, hypopituitarism, and visual function.  Results A total of 140 patients were included; 105 patients received SRS and 35 received FSRT between 2004 and 2015. Among SRS-treated patients, 41.11% (n=43) achieved biochemical remission at three years. In the FSRT group, no complete biochemical remissions were achieved at six years of follow-up.  Conclusions Stereotactic radiotherapy is an effective adjuvant treatment for acromegaly. SRS demonstrated progressive biochemical remission with acceptable long-term toxicity. FSRT remains a therapeutic alternative when SRS is not feasible. These findings, from a Latin American public neurosurgical center, endorse the feasibility of implementing stereotactic techniques in resource-limited settings.