Treatment outcome of metastasis to the pituitary gland: a case series of 21 patients with pathological diagnosis.

OBJECTIVE: The aim of this study was to report the treatment course of histologically confirmed metastases to the pituitary gland (pituitary metastasis). METHODS: The Mayo data explorer was used to find patients with pituitary metastasis. Twenty-one patients were identified between the years 2001 and 2021, and their data were retrospectively collected. RESULTS: The most common primary cancer origin was lung in men (45%) and breast in women (33%). The median age was 66 years (IQR 56-68 years). Patients presented with headache (67% [14/21]), vision problems (86% [18/21]), anterior hypopituitarism (71% [15/21]), and arginine vasopressin deficiency (38% [8/21]). Pituitary metastases were found before the diagnosis of the primary cancer in 5 patients (24%). The mean ± SD tumor size was 2.0 ± 0.7 cm, and 90% (19/21) presented as a solitary pituitary mass with no other intracranial metastatic lesions. Common radiological features were pituitary stalk thickening (90% [19/21]), cavernous sinus involvement (71% [15/21]), and constriction at the diaphragma sellae (52% [11/21]). Transsphenoidal surgery was performed in 20 patients, and subtotal resection was most frequently attained (76% [16/21]). Fourteen patients (67%) had adjuvant radiation therapy, and 15 patients (71%) were treated with systemic therapy. The median time from surgery to the initiation of radiation therapy was 16 days (IQR 11-21 days), and that from surgery to the initiation of systemic therapy was 5.0 months (IQR 1.5-14 months). During management, headaches improved in 57% (8/14) and vision problems improved in 61% (11/18) of cases; new hypopituitarism occurred in 5 patients. Six patients developed recurrence, and the median progression-free survival was 24 months (95% CI 5.4-43 months). After recurrence, 1 patient with adenoid cystic carcinoma was treated with rescue radiotherapy twice, and 4 patients responded well to systemic therapy. The median overall survival (OS) was 25 months (95% CI 7.1-43 months). The mean OS was better in patients with neuroendocrine lung tumor (261 months) and papillary thyroid carcinoma (80 months) and worse in patients with small cell lung cancer (4 months) and unknown origin (5 months). CONCLUSIONS: Surgery with or without adjuvant radiotherapy is effective for mass reduction, rapid symptomatic improvement of vision and headaches, and definitive diagnosis. Even after local tumor control failure, some patients still benefit from radiation and/or systemic therapy.