Stereotactic ablative radiation therapy for spinal metastases: experience at a single Brazilian institution

Background: This study aims to assess the clinical outcomes of patients with spine metastases who underwent stereotactic ablative radiation therapy (SABR) as part of their treatment. SABR has arisen as a contemporary treatment option for spinal metastasis patients with good prognoses. Materials and methods: Between November 2010 and September 2018, Spinal SABR was performed in patients with metastatic disease in different settings: radical (SABR only), postoperative (after decompression and/or fixation surgery), and reirradiation. Local control (LC), pain control, overall survival (OS) and toxicities were reported. Results: Eighty-five patients (corresponding to 96 treatments) with spine metastases were included. The median age was 59 years (range, 23–91). In most SABR (82.3%, n = 79) was performed as the first local spine treatment, while in 12 settings (12.5%), fixation and/or decompression surgery was performed prior to SABR. Two-year overall survival rate was 74.1%, and median survival was 19 months. The LC rate at 2 years was 72.3%. With regard to pain control, among 67 patients presenting with pain before SABR, 83.3% had a complete response, 12.1% had a partial response, and 4.6% had progression. Vertebral compression fractures occurred in 10 patients (11.7%), of which 5 cases occurred in the reirradiation setting. Radiculopathy and myelopathy were not observed. No grade III or IV toxicities were seen. Conclusion: This is the first study presenting a Brazilian experience with spinal SABR, and the results confirm its feasibility and safety. SABR was shown to produce good local and pain control rates with low rates of adverse events

Dinâmica do potássio nos resíduos vegetais de plantas de cobertura no Cerrado Potassium dynamics in crop residues of cover plants in Cerrado

A produção de biomassa, a manutenção dos resíduos vegetais sobre o solo e sua posterior decomposição são fatores de grande importância no estudo da ciclagem de nutrientes. Este estudo foi desenvolvido na área experimental do CEFET-Uberaba-MG, onde foram avaliados oito tipos de coberturas vegetais: milheto (Pennisetum americanum sin. tiphoydes), braquiária (Brachiaria brizantha), sorgo-forrageiro (Sorghum bicolor L. Moench), guandu (Cajanus cajan (L.) Mill sp.), crotalária (Crotalarea juncea), aveia-preta (Avena strigosa Schreb), pousio e área em preparo convencional de solo (testemunha) em área de Cerrado, na região do Triângulo Mineiro. Avaliaram-se a fitomassa seca (FS), a decomposição dos resíduos em bolsas de decomposição, e a liberação de K. Utilizou-se um modelo matemático para descrever a decomposição dos resíduos e a liberação de K, e calcularam-se a constante de decomposição (k) e o tempo de meia-vida (T½). O milheto, o sorgo e a crotalária foram as coberturas que apresentaram maiores produções de matéria seca. O maior acúmulo de K ocorreu em gramíneas e a maior liberação de K ocorreu no milheto, aveia, braquiária e crotalária nos primeiros 42 dias após manejo, nos dois períodos avaliados. A braquiária apresentou o menor T½ vida e a maior taxa de liberação de K.<br>Crop residue production, plant residue maintenance and their decomposition are important factors in the understanding of nutrient recycling process. To evaluate K accumulation and release a study with eight cover crops types was developed: pearl millet (Pennisetum americanum sin. tiphoydes), brachiaria grass (Brachiaria brizantha), sorghum (Sorghum bicolor L. Moench), pigeonpea (Cajanus cajan (L.) Millsp), sunn hemp (Crotalarea juncea) and black oats (Avena strigosa Schreb), fallow land and conventional culture (control) in the experimental area of CEFET-Uberaba-MG, in a Cerrado area. The dry mass production, crop residue decomposition in litter bags and K release were evaluated. A mathematical model was used to describe residue decomposition and K release, which calculates the decomposition constant (k) and half-time life. Pearl millet, sorghum and the sunn hemp were the cover crops that produced most dry matter while K accumulation was highest in the grasses. K release was highest in pearl millet, oats, brachiaria grass and sunn hemp in the first 42 days after handling. Brachiaria grass had the shortest half-time life and the highest K release rate