Radiologic follow-up of non-functioning pituitary adenomas: rationale and cost effectiveness.

Patients with non-functioning pituitary adenomas (NFPAs) are followed-up with serial endocrine, ophthalmologic and radiological assessment. There is a lack of evidence based guidance regarding the frequency and duration of radiological assessment during follow-up. We retrospectively analysed the details of follow-up radiological scanning in a cohort of patients diagnosed with NFPAs in an attempt to devise a rational and cost effective scanning schedule for use in routine clinical practice. 49 patients were identified using the hospital endocrine register. A detailed review of the case notes and follow up scans was undertaken. The data was analysed using descriptive statistics and Kaplan-Meier survival analysis using SPSS ver 13.0 (SPSS Inc. Chicago, IL). The time in which the tumor size in the followed up patients reached a state of 'no change' which persisted for at least two further scans was calculated. 41 patients, followed up for a median duration of 70 months were ultimately analysed. 33 patients had surgery while eight were conservatively managed. The time taken by 50% of tumors to achieve a steady state of 'no change' in tumor size on scans was 30 months. 90% of tumours achieved this state in 88 months. Surgical management did not significantly influence the time required to attain the steady state on a Kaplan-Meier analysis (Log rank test P = 0.06). NFPAs need extended follow-up since late recurrences after treatment are known. Routine radiologic follow up may be uneconomical after the steady state is achieved. Regular Goldmann perimetry beyond this time may be of greater use in selecting patients who actually need repeat surgical debulking. This method of follow up is likely to be more cost effective and reduce the number of scans performed.