Treatment of acromegaly: is there still a place for radiotherapy?

To evaluate efficacy and safety of radiotherapy on acromegaly treatment.

We followed retrospectively 99 acromegalic patients for at least one year after radiotherapy (RT). RT had been performed after unsuccessful surgery in 91 patients and as primary treatment in eight. Time elapsed between surgery and RT was 1.4 +/- 2.4 years. Mean follow-up after RT was 5.9 +/- 4.7 years (1-16 years). All patients were treated with linear accelerator, 89 by conventional (3240-6000 cGY) and ten by stereotactic RT.

Biochemical remission was defined as GH < 2.5 ng/ml and IGF-I normalization.

At latest follow-up, 54% of patients had serum GH level <2.5 ng/ml; 42% had normal IGF-I and 38% of patients achieved normalization of both. Controlled patients had lower baseline GH and IGF-I levels compared to uncontrolled ones. They achieved remission after 3.8 +/- 2.4 years, a significantly lower time length compared to maximum follow-up of uncontrolled (6.0 +/- 4.9 year). Results regarding GH and IGF-I levels were similar in patients treated either primarily or after surgery. No patient showed tumor growth. Visual field defects were observed in four, seizures in one, and mental disorders in two patients, although cognitive function were not properly assessed. At the last follow-up, 47% of patients had acquired at least one hormonal deficiency.

There is still a place for RT in acromegaly treatment, mainly for: after non-curative surgery and poor response or inaccessibility to medical treatment; growth restraining of aggressive macroadenomas; co-morbidities that contraindicate surgery and surgery refusal. However, side effects and latency period to achieve disease control should be kept in mind.