Efficacy and safety of fractionated conformal radiation therapy in acromegaly: a long-term follow-up study.

Abstract

Conformal, fractionated radiation therapy (XRT) is variably used as a treatment alternative for active acromegaly patients, usually, after failed pituitary surgery. Our objective was to evaluate the long-term efficacy and safety of XRT using strict criteria of biochemical control. Retrospective cohort study of 94 patients (73 women, mean age at radiation 53.16 ± 12.9 years) attending a specialized multidisciplinary clinic between 1998 and 2014 with a mean duration of follow-up of 12.9 ± 7.3 years. A basal growth hormone < 1 ng/mL and an IGF-1 < 1.2 × the upper limit of normal was achieved by 41% and 50.8%, respectively, at 5 years of follow-up, and by 44% and 66%, respectively, 10 years after XRT. Median tumor volume decreased significantly from 904 mm3 at baseline to 424 mm3 upon last follow-up (p = 0.01). The prevalence of central hypogonadism, central hypocortisolism, and central hypothyroidism increased from 18%, 35%, and 35% at baseline, to 38%, 53%, and 64%, respectively, after 10 years of follow-up. One patient was diagnosed with a meningioma and another one developed optic neuritis. No cerebrovascular events were recorded, and all patients are currently alive. XRT is an effective and reasonably safe means of controlling acromegalic activity. Its main disadvantages are the time required to achieve biochemical control and the development of anterior pituitary hormone deficiencies.