Tumor Control and Long-Term Survival in Non-Functional Pituitary Adenoma Treated with Adjuvant Radiotherapy. A Retrospective Single Institutional Study.

Abstract

Background: Radiation therapy (RT) for postoperative residual or progressive non-functioning pituitary adenomas (NFPAs) has excellent long-term local control (LC) although its use has been limited because of the potential late toxicity related to radiation treatments. Newer techniques have led to better precision.

Objective: The objective of the study was to review the institutional outcomes of NFPA treated with postoperative RT.

Methods and materials: One hundred forty-seven patients of NFPA were treated at our institution from 2006 to 2018. Ninty-one patients who received RT post-surgery were included in the analysis. RT was delivered to a dose of 45Gy in 25 fractions over 5 weeks using contemporary RT techniques. Patients with residual disease or recurrence after debulking surgery were treated with RT. Magnetic resonance imaging (MRI) for response was available in 70 patients. Effects of age, gender, cavernous sinus invasion (CSI), bony erosion, number of surgeries, MIB index, p53 status, and RT technique on overall survival (OS) were analyzed.

Results: The median follow-up of the patients was 86.5 months (IQR: 53-126). The 10y OS was 88.9%. Of the 70 patients who had follow-up MRI, the 10y LC post-adjuvant RT was 97.1%. On univariate analysis, multiple surgeries were associated with better OS compared to patients who underwent single surgery (P = 0.012), and the presence of both bony erosion and CSI was significantly associated with poorer OS (P = 0.028).

Conclusion: Radiotherapy after debulking surgery in a select group of patients with NFPA gives excellent tumor control and survival. The presence of extrasellar extensions results in poor clinical outcomes.