Organ At Risk (OAR) Data on Clinical Toxicity in The Treatment of Bulky Adrenal Metastases With Stereotactic Ablative Radiotherapy (SABR)

Aim: In this study, the effectiveness of the treatment was investigated in terms of treatment responses and side effects with OAR in oligometastatic patients whose adrenal metastases were treated with stereotactic ablative radiotherapy. Methods: Medically inoperable patients who underwent radiosurgery for adrenal gland metastasis in our clinic between 2013 and 2019 were evaluated retrospectively withfor the patient, tumor, treatment characteristics, survival outcomes, and dosimetric parameters with toxicity.Results: Of the 22 patients in our study, 17 were male and 5 were female, with the median age of 63 (RangeRange (R): 41-81) years. PrimaryThe primary tumor site was the lung in 20 (90.9%) of 22 patients, while ten (45.5%) of the patients had isolated adrenal metastasis. The median dose was 30 Gy (R: 18-50) with a median fraction of five (R: 3-10). MedianThe median PTV volume was 55 cc. (IQR(interquartile range): 44-120cc).Conformity120 cc). The conformity index (CI) was 1.15 (R: 0.94-1.55), the homogeneity index (HI) was 1.27 (R: 0.7-1.47), and the coverage was 97.87% (33.33-99.04). From the first diagnosis to adrenal gland radiotherapy, the median time was 6.9 (IQR: 0.5-14) months. The median follow-up was 7 months (R: 2-48), and the median survival was 9.5 months (R: 2-48). The local control rate was 72.7% in the 6th month, 63.6% in the 1st year, and 59.0% in the 2nd year, and overall survival was 72.7%, 50%, and 31.8%, respectively. The median overall survival was 9.5 months for all patients (p= 0.049) and 6.5 months in the presence of diffuse disease. Deaths of patients due to distant progression were also found to be significant (p = 0.03, which was significant). Patients with isolated adrenal metastasis survived for 14.4 months after the treatment; while extra-adrenal metastasis lived for a median of 6.6 months (P = 0.01). Patients without distant progression survived for 16.7 months, and those with distant progression survived for a median of 8.7 months. Treatment-related toxicity grade 3-4 developed in 2 patient patients in which this toxicity was related to the gastrointestinal system. No grade 3 toxicity was detected in the kidney.Conclusion: Maintaining the local control of the adrenal gland metastasis in patients with oligometastatic disease not only provides symptom control, but may also provide prolonged survival with minimal toxicity.