Role of radiotherapy in extracranial metastatic malignant melanoma in the modern era

Background: To assess the role of radiotherapy in metastatic malignant melanoma (MM) patients in modern era. Materials and methods: This is a retrospective study of MM patients treated with radiotherapy at Mayo Clinic from 1999 to 2014. Patients with pre- and post-treatment imaging studies (CT, MRI, and/or PET/CT) were assessed for metastasis failure (MF), regional/distant failure, and overall survival (OS). Results: In 75 MM patients, 56 and 68 lesions were treated with conventional/hypofractionated radiotherapy (CHRT) and stereotactic body radiotherapy (SBRT), respectively. The median doses for CHRT and SBRT were 30 Gy and 50 Gy, respectively. 1-year MF was 17% (SBRT 6% vs CHRT 31%, p < 0.01). 1-year regional (5% vs 29%, p < 0.01) and distant progression (75% vs 89%, p < 0.01) were improved with SBRT. Median OS was 15.6 months (CHRT 7.0 vs SBRT 22.9, p < 0.01). Prognostic factors for OS included age ≤55 years (RR 0.25), oligometastatic disease (RR 0.34), SBRT (RR 0.38) and treating all lesions (RR 0.28, all p < 0.01). Conclusions: SBRT for extracranial MM exhibited improved MF compared with CHRT, consistent with intracranial radiosurgery data. Though these data are retrospective and subject to selection bias, our findings support the prudent use of SBRT in a select group of favorable, oligometastatic MM patients, and should be discussed as an alternative to surgery and ablation

Role of radiotherapy in extracranial metastatic malignant melanoma in the modern era

Background: To assess the role of radiotherapy in metastatic malignant melanoma (MM) patients in modern era. Materials and methods: This is a retrospective study of MM patients treated with radiotherapy at Mayo Clinic from 1999 to 2014. Patients with pre- and post-treatment imaging studies (CT, MRI, and/or PET/CT) were assessed for metastasis failure (MF), regional/distant failure, and overall survival (OS). Results: In 75 MM patients, 56 and 68 lesions were treated with conventional/hypofractionated radiotherapy (CHRT) and stereotactic body radiotherapy (SBRT), respectively. The median doses for CHRT and SBRT were 30 Gy and 50 Gy, respectively. 1-year MF was 17% (SBRT 6% vs CHRT 31%, p < 0.01). 1-year regional (5% vs 29%, p < 0.01) and distant progression (75% vs 89%, p < 0.01) were improved with SBRT. Median OS was 15.6 months (CHRT 7.0 vs SBRT 22.9, p < 0.01). Prognostic factors for OS included age ≤55 years (RR 0.25), oligometastatic disease (RR 0.34), SBRT (RR 0.38) and treating all lesions (RR 0.28, all p < 0.01). Conclusions: SBRT for extracranial MM exhibited improved MF compared with CHRT, consistent with intracranial radiosurgery data. Though these data are retrospective and subject to selection bias, our findings support the prudent use of SBRT in a select group of favorable, oligometastatic MM patients, and should be discussed as an alternative to surgery and ablation

Prospective trial evaluating the sensitivity and specificity of 3,4-dihydroxy-6-[18F]-fluoro-l-phenylalanine (18F-DOPA) PET and MRI in patients with recurrent gliomas

Treatment-related changes can be difficult to differentiate from progressive glioma using MRI with contrast (CE). The purpose of this study is to compare the sensitivity and specificity of 18F-DOPA-PET and MRI in patients with recurrent glioma. Thirteen patients with MRI findings suspicious for recurrent glioma were prospectively enrolled and underwent 18F-DOPA-PET and MRI for neurosurgical planning. Stereotactic biopsies were obtained from regions of concordant and discordant PET and MRI CE, all within regions of T2/FLAIR signal hyperintensity. The sensitivity and specificity of 18F-DOPA-PET and CE were calculated based on histopathologic analysis. Receiver operating characteristic curve analysis revealed optimal tumor to normal (T/N) and SUVmax thresholds. In the 37 specimens obtained, 51% exhibited MRI contrast enhancement (M+) and 78% demonstrated 18F-DOPA-PET avidity (P+). Imaging characteristics included M−P− in 16%, M−P+ in 32%, M+P+ in 46% and M+P− in 5%. Histopathologic review of biopsies revealed grade II components in 16%, grade III in 43%, grade IV in 30% and no tumor in 11%. MRI CE sensitivity for recurrent tumor was 52% and specificity was 50%. PET sensitivity for tumor was 82% and specificity was 50%. A T/N threshold &gt; 2.0 altered sensitivity to 76% and specificity to 100% and SUVmax &gt; 1.36 improved sensitivity and specificity to 94 and 75%, respectively. 18F-DOPA-PET can provide increased sensitivity and specificity compared with MRI CE for visualizing the spatial distribution of recurrent gliomas. Future studies will incorporate 18F-DOPA-PET into re-irradiation target volume delineation for RT planning