Retrospective study of long-term outcomes of adjuvant proton radiotherapy for residual pituitary adenoma in adults

Pituitary adenomas (PA) are benign neoplasms treated by resection. Gross total resection is limited by extrasellar expansion in proximity to critical neurovascular structures. A retrospective study at Heidelberg University Hospital (Heidelberg, Germany) evaluated adjuvant proton radiotherapy (PRT) for 22 residual PA, including 16 non-functioning (NFPA) and 6 functioning (FPA). At median follow-up of 65 monts, 5-year local tumor control rate of FPA and NFPA and hormone control rate of FPA was 100%. Secondary hypopituitarism after PRT was rare (1/22). Stable endocrine status during follow-up enabled significant reductions in required glucocorticoid supplementation. Visual improvement was reported in 64%. Toxicity was limited, with fatigue and headache being most frequent. The authors conclude that adjuvant PRT for complex residual PA is efficacious and safe for treating residual disease in extrasellar expansion.