Non-functioning Pituitary Macroadenomas – Long-term Surveillance without Intervention

Introduction:
The treatment strategy for non-functioning pituitary adenomas (NFPA) includes surgery, radiotherapy, medical treatment, or follow-up. Series of non-operated patients with NFPAs who were followed-up without intervention are limited and included only a small number of patients. This study investigated the natural history of patients with NFPAs who were followed-up without intervention.

Methods:
This retrospective study performed at Rabin Medical Center, included patients with NFPA>10 mm who were naïve to surgery or medical treatment, and followed > 12 months after diagnosis. Follow-up included evaluation of tumor size by MRI, visual disturbances, and hormonal levels. Follow-up terminated if the patient underwent surgery, received Cabergoline or was lost to follow-up. Tumor growth was defined as maximal diameter increase of 2mm or more.

Results:
The cohort included 50 patients (30 males) with a mean age at diagnosis of 69.0±12.0 years. The average maximal tumor size was 17.6±6.0 mm. Mean follow-up was 5.8±5.1 years. Increase in tumor size occurred in 17 patients, with an average growth of 5.1±4.2 mm. Reduction in tumor size occurred in 13 patients, with a mean decrease of 4.3±2.8 mm. Overall, 33 patients (66%) were observed without intervention and 17 patients were operated (n=3) or treated with Cabergoline (n=14) because of tumor growth, symptoms appearance or proximity to the optic chiasm. Age, gender, tumor size, invasiveness, visual disturbances, and hypopituitarism were not predictors of adenoma enlargement.

Conclusion:
Observation alone without intervention for macroadenomas should be considered in selected patients. This study did not identified predictors of tumor growth.