RADIOTHERAPY VERSUS RADIOSURGERY IN TREATING PATIENTS WITH ACROMEGALY: A SYSTEMATIC REVIEW AND META-ANALYSIS.

OBJECTIVE: 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 and compare outcomes for SRS and RT in patients with acromegaly. METHODS: 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 insulin-like growth factor-I (IGF-I) and growth hormone (GH) levels, biochemical remission, all-cause mortality, hypopituitarism, headaches, and secondary malignancies. We pooled outcomes using a random-effects model. RESULTS: The final search yielded 30 eligible studies assessing 2,464 patients. Compared to RT, SRS was associated with a nonsignificant increase in remission rate at the latest follow-up period (52% vs. 36%; P = .14) and a significantly lower follow-up IGF-I level (-409.72 μg/L vs. -102 μg/L, P = .002). SRS had a lower incidence of hypopituitarism than RT; however, the difference was not statistically significant (32% vs. 51%, respectively; P = .05). CONCLUSION: SRS may be associated with better biochemical remission, and it had a lower risk of hypopituitarism with at least 1 deficient axis when compared with RT; however, the confidence in such evidence is very low due to the noncomparative nature of the studies, high heterogeneity, and imprecision. ABBREVIATIONS: GH = growth hormone GKRS = gamma-knife radio-surgery IGF-I = insulin-like growth factor-I LINAC = linear accelerator RT = conventional radiotherapy SRS = stereotactic radiosurgery.