Recurrence in acromegaly: two tertiary centers experience and review of the literature

Background: Recurrence of acromegaly after successful surgery is a rare event, but no clear data are reported in the literature about its recurrence rates. This study aimed to evaluate the recurrence rate in a series of acromegalic patients treated by transsphenoidal surgery (TSS) with a long follow-up. Methods: We retrospectively analyzed data from 283 acromegalic patients who underwent TSS at two pituitary units in Milan (Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico and IRCCS Humanitas Research Hospital). The diagnosis and recurrence of acromegaly were defined by both elevated IGF-1 levels and a lack of GH suppression based on appropriate criteria for the assay used at the time of diagnosis. Results: After surgery, 143 patients (50%) were defined as not cured, 132 (47%) as cured and 8 (3%) as partially cured because of normalization of only one parameter, either IGF1 or GH. In the cured group, at the last follow-up (median time 86.8 months after surgery), only 1 patient (0.7%) showed full recurrence (IGF-1 + 5.61 SDS, GH nadir 1.27 µg/l), while 4 patients (3%) showed only increased IGF1. In the partially cured group at the last follow-up, 2/8 (25%) patients showed active acromegaly (IGF-1 SDS + 2.75 and + 3.62; GH nadir 0.6 and 0.5 µg/l, respectively). Conclusions: In the literature, recurrence rates range widely, from 0 to 18%. In our series, recurrence occurred in 3.7% of patients, and in fewer than 1%, recurrence occurred with elevation of both IGF-1 and the GH nadir. More frequently (25%), recurrence came in the form of incomplete normalization of either IGF-1 or GH after surgery.