Endocrine Abstracts

Background and aim: Radiotherapy is an established treatment modality in the management of acromegaly, often used third-line, when surgery and medication don’t achieve remission. A few studies report outcomes from limited follow-up and no prognostic factors for treatment response were identified. We aimed to assess clinical outcomes of patients with acromegaly, who underwent radiotherapy and are currently under our follow-up.

Methods: We retrospectively collected demographic, radiological, treatment, biochemical and clinical outcomes on all patients with acromegaly under our follow-up, who received radiotherapy. Descriptive statistics and regression analysis were used for analysis.

Results: Forty-five of 155 patients (29%) with acromegaly completed radiotherapy. The majority of cases were fractionated, a minority received stereotactic and proton beam radiotherapy (7/45). Median age at diagnosis was 36.5 years (IQR 26.3-47.8). Mean follow-up was 10.5 years (range 2-28). Cure was achieved in 13/45 patients (28.9%), defined as no medication needed in 6/45 (13.3%) and medication stopped anywhere from immediately post radiotherapy to 17 years follow-up in the remaining 7/39 (17.9%). Medication de-escalation was achieved in 11/45 patients (24.4%) between 2-24 years follow-up. In 10/45 (22.2%) patients, disease stability was achieved on stable medication doses. In 11/45 (24.4%) of patients, medication was escalated for increased disease activity. Reduction in tumour volume was observed in 14 patients between 6 months to 6 years post radiotherapy, 35.7% of reductions reported at 1 year. In 9/45 (20%) patients hormone deficiencies developed from 2 months to 16 years post radiotherapy, with 4 patients having multiple pituitary axes affected.

Conclusion: Radiotherapy improved disease control in 53% cases. Given such response, potential for medication de-escalation and a more cost effective treatment pathway, radiotherapy should be considered earlier in appropriate cases, with appropriate counselling on the risks and establishment of long-term follow-up.