Review of Palliative Radiation Therapy Patterns of Practice for Adrenal Metastases in British Columbia.

Purpose: The adrenal gland is a common site of metastasis in patients with advanced cancer, but it is rarely symptomatic. A subset of patients develop a complex pain syndrome with anorexia, nausea, and poorly localized visceral pain in the back, flank, or epigastric region. These symptoms can affect quality of life and are occasionally challenging to palliate. The role of palliative radiation therapy (PRT) in these patients is unclear. This population-based retrospective study evaluates PRT practices for patients with adrenal metastases and aims to describe treatment response and acute toxicity.

Methods And Materials: Patients who received PRT to an adrenal metastasis between the years of 1985 and 2015 were identified in a provincial database. Patient demographics, tumor factors, symptom burden, radiation therapy prescriptions, and response to treatment were collected. Variables were summarized using descriptive statistics. The Kaplan-Meier test was used to assess survival. Factors associated with clinical response were evaluated using univariate and logistic regression analysis. Factors associated with survival were evaluated using univariate and Cox proportional hazards model.

Results: One hundred patients who received 103 separate courses of PRT were identified. The majority had a lung primary (82%). The most common baseline symptoms were pain (90%) and gastrointestinal upset (13%). Prescriptions ranged from 600 cGy in a single fraction to 4500 cGy in 25 fractions. Seventy percent of patients experienced an improvement in pain (either a complete or partial response). Forty-three percent of patients developed acute toxicity from treatment. Median survival was 3 months.

Conclusions: Compared with other anatomic sites, conventional PRT is uncommonly delivered to adrenal metastases. Despite heterogeneity in tumor histology and radiation therapy prescriptions, treatment was associated with an overall pain response of 70%. Prophylactic antiemetics to decrease radiation-induced nausea are required before treatment. Given the poor prognosis of this population, short fractionations are indicated.