Recommendations of the Spanish Societies of Radiation Oncology (SEOR), Nuclear Medicine & Molecular Imaging (SEMNiM), and Medical Physics (SEFM) on F-FDG PET-CT for radiotherapy treatment planning

Positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) is a valuable tool for diagnosing and staging malignant lesions. The fusion of PET and computed tomography (CT) yields images that contain both metabolic and morphological information, which, taken together, have improved the diagnostic precision of PET in oncology. The main imaging modality for planning radiotherapy treatment is CT. However, PET-CT is an emerging modality for use in planning treatments because it allows for more accurate treatment volume definition. The use of PET-CT for treatment planning is highly complex, and protocols and standards for its use are still being developed. It seems probable that PET-CT will eventually replace current CT-based planning methods, but this will require a full understanding of the relevant technical aspects of PET-CT planning. The aim of the present document is to review these technical aspects and to provide recommendations for clinical use of this imaging modality in the radiotherapy planning process

Mesenchymal Stromal Cell Irradiation Interferes with the Adipogenic/Osteogenic Differentiation Balance and Improves Their Hematopoietic-Supporting Ability

[EN]Bone marrow mesenchymal stromal cells (MSCs) are precursors of adipocytes and osteoblasts and key regulators of hematopoiesis. Irradiation is widely used in conditioning regimens. Although MSCs are radioresistant, the effects of low-dose irradiation on their behavior have not been extensively explored. Our aim was to evaluate the effect of 2.5 Gy on MSCs. Cells from 25 healthy donors were either irradiated or not (the latter were used as controls). Cells were characterized following International Society for Cellular Therapy criteria, including in vitro differentiation assays. Apoptosis was evaluated by annexin V/7-amino-actinomycin staining. Gene expression profiling and reverse transcriptase (RT)-PCR of relevant genes was also performed. Finally, long-term bone marrow cultures were performed to test the hematopoietic-supporting ability. Our results showed that immunophenotypic characterization and viability of irradiated cells was comparable with that of control cells. Gene expression profiling showed 50 genes differentially expressed. By RT-PCR, SDF-1 and ANGPT were overexpressed, whereas COL1A1 was downregulated in irradiated cells (P = .015, P = .007, and P = .031, respectively). Interestingly, differentiation of irradiated cells was skewed toward osteogenesis, whereas adipogenesis was impaired. Higher expression of genes involved in osteogenesis as SPP1 (P = .039) and lower of genes involved in adipogenesis, CEBPA and PPARG (P = .003 and P = .019), together with an increase in the mineralization capacity (Alizarin Red) was observed in irradiated cells. After differentiation, adipocyte counts were decreased in irradiated cells at days 7, 14, and 21 (P = .018 P = .046, and P = .018, respectively). Also, colony-forming unit granulocyte macrophage number in long-term bone marrow cultures was signifi- cantly higher in irradiated cells after 4 and 5 weeks (P = .046 and P = .007). In summary, the irradiation of MSCs with 2.5 Gy improves their hematopoietic-supporting ability by increasing osteogenic differentiation and decreasing adipogenesis

High-Risk Clinicopathological and Genetic Features and Outcomes in Patients Receiving Neoadjuvant Radiochemotherapy for Locally Advanced Rectal Cancer

Administering preoperative radiochemotherapy (RCT) in stage II-III tumors to locally advanced rectal carcinoma patients has proved to be effective in a high percentage of cases. Despite this, 20–30% of patients show no response or even disease progression. At present, preoperative response is assessed by a combination of imaging and tumor regression on histopathology, but recent studies suggest that various genetic abnormalities may be associated with the sensitivity or resistance of rectal cancer tumor cells to neoadjuvant therapy. In the present study we investigated the relationship between genetic lesions detected by high-density single-nucleotide polymorphisms (SNP) arrays 6.0 and response to neoadjuvant RCT, evaluated according to Dworak criteria in 39 rectal cancer tumors before treatment. The highest frequency of copy-number (CN) losses detected corresponded to chromosomes 18q (n = 27; 69%), 1p (n = 22; 56%), 15q (n = 19; 49%), 8p (n = 18; 48%), 4q (n = 17; 46%), and 22q (n = 17; 46%); in turn, CN gains more frequently involved chromosomes 20p (n = 22; 56%), 8p (n = 20; 51%), and 15q (n = 16; 41%). There was a significant association between alterations in the 1p, 3q, 7q, 12p, 17q, 20p, and 22q chromosomal regions and the degree of response to therapy prior to surgery. However, 4q, 15q11.1, and 15q14 chromosomal region alterations were identified as important by five prediction algorithms, i.e., those with the greatest influence on predicting the tumor response to treatment with preoperative RCT. Multivariate analysis of prognostic factors showed that gains on 15q11.1 and carcinoembryonic antigen (CEA) levels serum at diagnosis were the only independent variables predicting disease-free survival (DFS). Lymph node involvement also showed a prognostic impact on overall survival (OS) in the multivariate analysis. A deep-learning-based algorithm showed a 100% success rate in predicting both DFS and OS at 60 months after diagnosis of the disease. In summary, our results indicate the existence of an association between tumor genetic abnormalities at diagnosis, response to neoadjuvant therapy, and survival of patients with locally advanced rectal cancer. In addition to the clinical and biological characteristics of locally advanced rectal cancer patients, these could be used in the future as therapeutic and prognostic biomarkers, to identify patients sensitive or resistant to preoperative treatment, helping guide therapeutic decision-making. Additional prospective studies in larger series of patients are required to confirm the clinical utility of the newly identified biomarkers

Agreement in the assessment of metastatic spine disease using scoring systems

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