Can we ever stop imaging in surgically treated and radiotherapy-naive patients with non-functioning pituitary adenoma?

BACKGROUND: Non-functioning pituitary adenomas (NFAs) are slow-growing tumours with reported re-growth rates following surgical resection alone of up to 50% at 10 years. Currently, the desired length of follow-up surveillance imaging in un-irradiated patients is unclear.

AIM: To clarify the timing of re-growth in patients with NFAs, treated solely by surgery without post-operative pituitary radiotherapy, and also to clarify whether continued imaging is necessary in these patients.

METHODS: A case note analysis of all patients who underwent surgery alone for NFA between January 1984 and December 2007 was undertaken. Patients were followed for a minimum of 1 year. Re-growth was diagnosed on the basis of radiological appearances with or without associated manifestations.

RESULTS: One hundred and fifty-five patients (94 males, mean age at diagnosis 57.9 (range 18.3-88) years) were included. Twenty-nine were followed up for more than 10 years. The mean follow-up following surgery was 6.1 years (median 4.3 (range 1-25.8)). Re-growth was documented in 54 (34.8%) cases and 20.4% of these cases showed relapse/re-growth 10 or more years after the initial surgery. Kaplan-Meier analysis showed relapse rates of 23.1, 46.7 and 67.9% at 5, 10 and 15 years respectively. There was a significant increase in the re-growth rates if there was either pituitary tumour remnant observed on the first post-operative scan (P≤0.001) or a younger age at initial surgery (P=0.034).

CONCLUSION: These results suggest that patients with NFAs need to be closely monitored following surgery, particularly those with post-operative tumour remnants. With 20% of relapse occurring after 10 years, follow-up surveillance needs to be continued beyond this time.