Radiation treatment strategies for acromegaly

Abstract

<jats:p>The high morbidity and mortality associated with acromegaly can be addressed with multiple treatment modalities, including surgery, medicines, and radiation therapy. Radiation was initially delivered through conventional fractionated radiotherapy, which targets a wide area over many treatment sessions and has been shown to induce remission in 50%–60% of patients with acromegaly. However, conventional fractionated radiotherapy takes several years to achieve remission in patients with acromegaly and carries a risk of hypopituitarism that may limit its use. Stereotactic radiosurgery, of which there are several forms, including Gamma Knife surgery, CyberKnife therapy, and proton beam therapy, offers slightly attenuated efficacy but achieves remission in less time and provides more precise targeting of the adenoma with better control of the dose of radiation received by adjacent structures such as the pituitary stalk, pituitary gland, optic chiasm, and cranial nerves in the cavernous sinus. Of the forms of stereotactic radiosurgery, Gamma Knife surgery is the most widely used and, because of its long-term follow-up in clinical studies, is the most likely to compete with medical therapy for first-line adjuvant use after resection. In this review, the authors outline the major modes of radiation therapies in clinical use today, and they critically assess the feasibility of these modalities for acromegaly treatment. Acromegaly is a multisystem disorder that demands highly specialized treatment protocols including neurosurgical and endocrinological intervention. As more efficient forms of pituitary radiation develop, acromegaly treatment options may continue to change with radiation therapies playing a more prominent role.</jats:p>

Clinical Features and Treatment of Pediatric Somatotropinoma: Case Study of an Aggressive Tumor due to a New <i>AIP</i> Mutation and Extensive Literature Review

“…None received primary radiotherapy. In contrast to surgery and pharmacotherapy, radiotherapy has delayed effects, with several years being needed to achieve disease control [25,39]. Conventional fractionated radiotherapy achieves a biochemical remission in 35–75% of patients, usually after 10 years [39].…”

Composite MET-PET Fusion MRI is a Novel Method to Determine Adjuvant Therapy for Growth Hormone Secreting Adenomas

“…Notably, the remission rate following gamma knife radiosurgery based on MET-PET findings tended to be higher than that based on MRI findings. Furthermore, the time to remission is shorter with MET-PET-based dose planning for radiosurgery compared with MRI-based dose planning [11][12][13][14]. Because of the small number of patients and the size of the residual tumor [15] differed between patients, we cannot reach a conclusion on the superiority of either method.…”

“…In terms of gamma knife adjuvant therapy, the sequential changes in IGF-1 after gamma knife radiosurgery differ between MRI-based dose planning (Figure 4) [11][12][13] and MET-PET-based dose planning ( Figure 1). Notably, the remission rate following gamma knife radiosurgery based on MET-PET findings tended to be higher than that based on MRI findings.…”

Editorial

“…There is, however, no compelling evidence to support this. Loss of pituitary function after either therapy is usually limited to 1 or 2 pituitary functions, rather than panhypopituitarism, and it occurs over several years, accumulating for 10-15 years after treatment, as summarized in the current issue in reports by Stapleton et al 8 and Yang et al 9 Because with radiosurgery we have access to very few studies with follow-up durations beyond 5 years (see the tables in the reports by Rowland et al, 7 Stapleton et al, 8 and Yang et al 9 ), the true incidence of adverse effects on pituitary function over time cannot be known until the data to measure it are available. For instance, in the only radiosurgery series with a minimum median follow-up of 10 years, 6 46% of patients with acromegaly who underwent radiosurgery had endocrine remission at 10 years and 50% developed new anterior pituitary insufficiencies, the majority of which appeared more than 5 years after treatment.…”