Deferred Radiotherapy After Debulking of Non-functioning Pituitary Macroadenomas: Clinical Outcomes

Background: To describe the outcome for a cohort of patients with non-functioning pituitary macroadenomas (NFPMA), managed by debulking surgery with radiation therapy delayed until progression. Methods: Two hundred and sixty-seven patients were treated surgically for pituitary tumors at our institution between 1997 and 2005. One hundred and twenty-six patients met the inclusion criteria of NFPMA. They were followed for at least 2 years. Results: At presentation, 58% of patients had objectively decreased visual function, 66% had endocrine abnormalities, and 46% had headaches. Of the entire cohort, 75% of tumors abutted the optic chiasm and 87% had suprasellar extension. Over a median follow up of 112 months from surgery, 52% of patients had evidence of radiographic tumor progression, and 39% required additional treatment. There was a significant difference freedom from progression and in the number of patients receiving additional treatment with preoperative adenoma size of < 2 vs. ≥2 cm (p < 0.05). Conclusion: Close observation with radiation therapy delayed until the time of progression is an appropriate option for patients presenting with initial adenoma size < 2 cm, and can be considered for those with initial sizes up to 4 cm, as the majority of patients do not require further intervention for 10 or more years, thereby meaningfully postponing the risks of radiotherapy.