Tumor characteristics and clinical outcomes in 113 patients with acromegaly: exploratory analysis of the role of histologic invasion of adjacent tissues

Abstract

Background: Acromegaly, almost always caused by growth-hormone (GH)-secreting pituitary adenomas (PAs), leads to significant morbidity and mortality when left untreated. Surgical resection is the gold standard treatment, but biochemical remission following surgery occurs in only 40-60% of patients. We aimed to investigate characteristics of and outcomes in a large cohort of patients who underwent surgery for treatment of acromegaly from a GH-secreting tumor.

Methods: We analyzed a cohort of 113 patients who underwent surgery for resection of GH-secreting PAs at a single institution. We evaluated tumor characteristics and clinical and histopathologic factors affecting remission rates following surgery. Additionally, a smaller cohort of 20 GH-secreting PAs were found to have histologic evidence of invasion of either the bone, mucosa, cavernous sinus walls, or other dura. We investigated the characteristics of invasion and its prognostic value for these tumors.

Results: A total of 113 patients underwent resection of GH-secreting PAs. Histologic analysis revealed invasion of bone, dura, or mucosa in 20 patients (17.7 %). Of the total cohort, 66 patients (58.4 %) achieved biochemical remission with surgery alone. An additional 6 patients (5.3 %) achieved remission with meds, and 5 patients (4.4 %) achieved remission with additional surgery. In patients with evidence of invasion, pre-operative growth hormone levels were higher (32.0 vs 15.5, p = 0.020), tumors were larger (6.2 vs 3.0 cm³, p = 0.011) and the risk of post-operative CSF leak was higher (25 % vs 9.7 %, p = 0.012). There was a trend toward lower odds of biochemical remission in patients with invasive tumors (OR = 0.348, p = 0.058).

Conclusions: In patients undergoing resection of growth hormone-secreting tumor for treatment of acromegaly, microscopic invasion of tissues is relatively common and portends an increased risk of failure of surgical biochemical remission. Identification of microscopic invasion may allow for more aggressive surgical management and better chances of surgical control of disease.