Does Preoperative Somatostatin Analog Treatment Improve Surgical Cure Rates in Acromegaly? A New Look at an Old Question

Abstract

A cromegaly is caused in most cases by chronic GH hypersecretion from a pituitary adenoma. Typically, acromegaly has an insidious onset, with patients often suffering from unrecognized signs and symptoms for up to a decade before diagnosis (1). Apart from the characteristic physical changes to the face and extremities, patients with acromegaly are at increased risk for cardiac disease and colorectal cancer (2-4). Retrospective cohort studies show that chronic GH hypersecretion increases mortality, which can be returned to normal with effective control of GH and IGF-I (5, 6). Surgery, usually via the transsphenoidal route, is first-line therapy for acromegaly in suitable and willing patients. The surgical cure rate is 70 -85% for noninvasive microadenomas and enclosed (noninvasive) macroadenomas, and for large macroadenomas and invasive tumors, the cure rate is lower (20 -50%); the overall cure rate is in the region of 55-65% (7). The expertise of the surgeon is a crucial element in the outcome of acromegaly, with dedicated pituitary neurosurgeons having better results (8).Somatostatin analogs (SSAs) are the main medical treatment for acromegaly, and some centers have more than 20-yr experience with these compounds. In general, SSAs are used as an adjuvant therapy in patients whose symptoms and hormone abnormalities are not completely controlled by surgery. Primary therapy with a SSA is increasing in popularity, particularly among elderly or infirm subjects, or among those unwilling to undergo surgery. Adjuvant SSA therapy normalizes GH and IGF-I in 49 -56% and 48 -66% of patients, respectively (9). Primary SSA treatment controls GH and IGF-I in approximately 50 and 60% of patients, respectively. SSAs are also associated with tumor shrinkage in acromegaly, with approximately 37% of patients showing some decrease in tumor size during primary medical therapy (10), and 21% of those receiving adjuvant SSA treatment (11). This tumor shrinkage does not appear to be due to tumoricidal or strong pro-apoptotic effects but, rather, to a

Preoperative octreotide treatment of acromegaly: long-term results of a randomised controlled trial

“…According to the study protocol, the patients were followed and evaluated annually until 5 years after surgery. Long-term observational data in these patients are of importance, also because a concern has been raised of a potential lingering effect of preoperative SSA at the very early post-operative evaluation resulting in potential false positive results (18,19).…”

Autozhel' v kontrole biokhimicheskikh markerovaktivnosti akromegalii: predstavlenieklinicheskogo sluchaya

“…Эффекты лечения Соматулином ® Аутожель ® изу -чались как в краткосрочных (до 1 года) [4,7,11,12], так и длительных (до 3 лет) исследованиях в сравнении с Соматулином продленного действия и Сандостатином ЛАР, в которых он показал равнозначную эффективность с препаратами сравнения [4,24,26], что в целом также на-блюдалось на примере представляемой нами пациентки.…”

“…У нашей пациентки мы не наблюдали каких-либо изменений размеров микроаденомы гипофиза при проведении МРТ-исследования через 24 месяца от на-чала лечения, но способность препаратов ланреотида вызывать эффект сжатия опухоли гипофиза заслужи-вает особого внимания [4,7]. В исследовании Alexopoulou О. и соавт.…”

“…Но все же, результаты хирургического вмешательства значительно варьируют и определяются множеством факторов, в частности, размерами и взаимоотношением опухоли с соседними жизненно важными структурами [7].…”

American Association of Clinical Endocrinologists and American College of Endocrinology Disease State Clinical Review: Management of Acromegaly Patients: What is the Role of Pre-Operative Medical Therapy?

“…Variations in the GH and IGF-1 assays and definitions of normal changed over time, thus complicating one's ability to assess study efficacy (18,19).…”