The appropriate follow-up of patients with clinically non-functional pituitary adenomas (CNFPAs) after trans-sphenoidal surgery is controversial, and has limited evidence-based recommendations.[37]Mercado M, Melgar V, Salame L, et al. Clinically non-functioning pituitary adenomas: pathogenic, diagnostic and therapeutic aspects. [in spa]. Endocrinol Diabetes Nutr. 2017 Aug-Sep;64(7):384-95.
http://www.ncbi.nlm.nih.gov/pubmed/28745610?tool=bestpractice.com
[55]Freda PU, Beckers AM, Katznelson L, et al. Pituitary incidentaloma: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011;96:894-904.
http://www.ncbi.nlm.nih.gov/pubmed/21474686?tool=bestpractice.com
[62]Ziu M, Dunn IF, Hess C, et al. Congress of Neurological Surgeons systematic review and evidence-based guideline on posttreatment follow-up evaluation of patients with nonfunctioning pituitary adenomas. Neurosurgery. 2016 Oct;79(4):E541-3.
https://journals.lww.com/neurosurgery/Fulltext/2016/10000/Congress_of_Neurological_Surgeons_Systematic.20.aspx
http://www.ncbi.nlm.nih.gov/pubmed/27635964?tool=bestpractice.com
[91]Chanson P, Raverot G, Castinetti F, et al. Management of clinically non-functioning pituitary adenoma. Ann Endocrinol (Paris). 2015 Jul;76(3):239-47.
https://www.sciencedirect.com/science/article/pii/S0003426615000955?via%3Dihub
http://www.ncbi.nlm.nih.gov/pubmed/26072284?tool=bestpractice.com
Patients with evidence for residual tumour after surgery need to be followed more closely. One meta-analysis pooled data from 19 studies of patients with CNFPAs after surgery, followed for a mean duration of 5.7 years: the recurrence rate was 12% in those with no evidence for residual tumour and 46% in patients with residual disease postoperatively.[92]Chen Y, Wang CD, Su ZP, et al. Natural history of postoperative nonfunctioning pituitary adenomas: a systematic review and meta-analysis. Neuroendocrinology. 2012;96(4):333-42.
http://www.ncbi.nlm.nih.gov/pubmed/22687984?tool=bestpractice.com
The recommendation for patients with pituitary micro-adenomas, especially with tumours <6 mm in size, is to obtain a follow-up MRI in 1 year with no further routine imaging study if the tumour is stable, unless the patient develops subsequent symptoms or signs suggestive of mass effect.[57]Orija IB, Weil RJ, Hamrahian AH. Pituitary incidentaloma. Best Pract Res Clin Endocrinol Metab. 2012 Feb;26(1):47-68.
http://www.ncbi.nlm.nih.gov/pubmed/22305452?tool=bestpractice.com
The Endocrine Society recommends repeating MRI in 1 year and then every 1 to 2 years for another 3 years, gradually reducing the frequency of imaging if the tumour size remains stable.[55]Freda PU, Beckers AM, Katznelson L, et al. Pituitary incidentaloma: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011;96:894-904.
http://www.ncbi.nlm.nih.gov/pubmed/21474686?tool=bestpractice.com
Patients with non-functional pituitary macro-adenomas need to be followed for life.
The risk of tumour growth for pituitary macro-adenomas is expected to be higher because the tumour has already shown a propensity to grow. One review of 14 observational studies on patients with CNFPAs showed tumour growth, over an observation period of 1 to 8 years, in 10% of patients with microadenomas and 23% of those with macroadenomas.[56]Huang W, Molitch ME. Management of nonfunctioning pituitary adenomas (NFAs): observation. Pituitary. 2018 Apr;21(2):162-7.
http://www.ncbi.nlm.nih.gov/pubmed/29280025?tool=bestpractice.com
There is no consensus, but a pragmatic approach would be to obtain a follow-up MRI at 6 months and then yearly for 5 years.[57]Orija IB, Weil RJ, Hamrahian AH. Pituitary incidentaloma. Best Pract Res Clin Endocrinol Metab. 2012 Feb;26(1):47-68.
http://www.ncbi.nlm.nih.gov/pubmed/22305452?tool=bestpractice.com
This can be followed by an imaging study every 2 to 3 years if the pituitary tumour is stable. This recommendation is in line with that of the Endocrine Society.[55]Freda PU, Beckers AM, Katznelson L, et al. Pituitary incidentaloma: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011;96:894-904.
http://www.ncbi.nlm.nih.gov/pubmed/21474686?tool=bestpractice.com
Some of these patients may require surgical intervention and they will need close follow-up with repeated MRI scans because of a high risk of recurrence.