Radiotherapy vs. Radiosurgery in Treating Patients with Acromegaly: Systematic Review and Meta-Analysis

When patients with acromegaly have residual disease following surgery, adjuvant radiation therapy is considered. Both stereotactic radiosurgery (SRS) and conventional fractionated radiotherapy (RT) are utilized. We conducted a systematic review and meta-analysis to synthesize the existing evidence to compare outcomes with SRS and RT in patients with acromegaly.

We searched Medline In-Process & Other Non-Indexed Citations, MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus through April 2014 for studies in which SRS or RT were used in patients with acromegaly. Outcomes evaluated were serum IGF-1 and GH levels, biochemical remission, all-cause mortality, hypopituitarism, headaches and secondary malignancies. We pooled outcomes using the random-effects model.

The final search yielded 30 eligible studies enrolling 2464 patients. When compared to RT, SRS was associated with a non-significant increase in remission rate at the latest follow-up period (52% vs. 36%; p = 0.14), and a significantly lower follow-up IGF-1 level (decline of - 409.72 μg/1 vs. -102 μg/1; p = 0.002). SRS was associated with lower incidence of hypopituitarism than RT; however the difference was not statistically significant [(32% vs.51%, respectively; p = 0.05).

SRS may be associated with better biochemical remission and lower risk of hypopituitarism with at least one deficient axis when compared with RT; however, the confidence in such evidence is very low due to the non-comparative nature of the studies, high heterogeneity, and imprecision.