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- PublicationTechnological Improvements in Low- and Middle-Income Countries (LMICs): A Review of the Literature and the “Sociedad de Lucha Contra el Cáncer” (SOLCA) Institutional Experience in Neuro-Radiosurgery During the Coronavirus Disease 2019 (COVID-19) Pandemic(World Neurosurgery, 2022-06-18) Ochoa, Pamela; Loza, Felipe; Cueva, Fiorella; Leon Rojas, Jose; Puente Vallejo, RaúlOBJECTIVE: Neurosurgery is a medical field that requires specialized professionals and equipment, 2 important but scarce resources in low- and middle-income countries. Our goal was to report our experience with the replacement and implementation of linear accelerators with radiosurgery capabilities at “Sociedad de Lucha Contra el Cáncer” (SOLCA) Hospital in Quito, Ecuador, and give some recommendations for future technological replacements (TRs). - METHODS: Two surveys were performed in SOLCA’s radiosurgery department, one before the TR was finalized and one after, consisting of an open and multiple-choice questionnaire. Questions focused on the performance of the new equipment, perceptions regarding the training, and the influence of the pandemic on the whole process. In addition, we share our experience regarding the difficulties and benefits of TR at SOLCA. - RESULTS: The most-reported limitation was lack of training (48%). By the time of the second survey, 95.2% of the staff had already treated patients or planned a radiosurgical procedure; 42.9% considered training to have been adequate, and 76.2% felt that the pandemic hindered the training process. Currently, 33 radiosurgeries have been done (26 for the central nervous system and 7 stereotactic radiation body therapies). - CONCLUSIONS: The TR in SOLCA had similarities with other experiences in low- and middle-income countries, but the pandemic brought additional limitations, mainly complicating the staff training. Nevertheless, those limitations can be resolved with a structured training program and international collaboration. Overall, the benefits obtained from a TR result in exponentially better medical care and accessibility to novel treatments.
- PublicationComparative study of chromosome aberrations induced with aphidicolin in women affected by breast cancer and cervix uterine cancer(Cancer Genetics and Cytogenetics, 1997-04-01) Paz-y-Miño, César; Peñaherrera, María Serena; Sánchez, María Eugenia; Córdova, Augusta; Gutiérrez, Sara; Ocampo, Ligia; Leone, Paola E.Blood samples were obtained from 80 women: Twenty of these samples were from women affected by ductal infiltrating breast carcinoma, twenty from women affected by cervix uterine cancer, and forty individuals were screened for a control group. The search for chromosome instability that is known to affect individuals with cancer was performed through chromosome analysis in nontumor cells, intending to establish frequency and different types of numerical and structural aberrations. The results, in regard to spontaneous and aphidicolin induced chromosome aberrations, showed a significantly greater frequency (p < 0.001) of chromosome fragility, as well as other numerical and structural aberrations in breast cancer patients when compared to the control group. Similar results were obtained from cervix uterine cancer patients with the exception of certain numerical aberrations in which no significant differences were found. This suggests the existence of a certain degree of chromosomal instability affecting individuals with both types of cancer. The increase in fragility may play an important role in the biologic behavior and progression of cancer.
- PublicationTelomeric Association in Women with Breast and Uterine Cervix Cancer(Cancer Genetics and Cytogenetics, 1997-10-01) Paz-y-Miño, César; Sánchez, María Eugenia; Del Pozo, Mercedes; Baldeón, María Augusta; Córdova, Augusta; Gutiérrez, Sara; Peñaherrera, María Serena; Neira, Marco; Ocampo, Ligia; Leone, Paola E.This study compares the frequency of telomeric associations in the peripheral blood of women suffering breast and cervix uterine cancer with a healthy control group. Two kinds of cultures were developed for each individual: with and without aphidicolin. In the normal cultures, the number of telomeric associations observed was 95.5 times higher in individuals affected by breast cancer and 41.3 times higher in those affected by cervix uterine cancer when compared to the control group (p < 0.001). In the cultures with aphidicolin, higher numbers of altered metaphases were observed in both groups as compared to the control groups (p < 0.001). Statistically significant differences (p < 0.001) could also be observed when comparing telomeric associations between the two types of cancer in both cultures. When we compared individuals affected by breast cancer in both types of cultures statistical differences were found (p < 0.05), and similar results were found in individuals affected by uterine cervix cancer (p < 0.001). The findings suggest that telomeric associations may be reflecting chromosome instability observed in cancer and that this instability behaves differently for various types of cancer.
- PublicationAnalysis of the polymorphism [gIVS12-6T>C] in the hMSH2 gene in Lymphoma and Leukemia(Leuk Lymphoma, 2003-03-01) Paz-y-Miño, César; Fiallo, B. Fernanda; Morillo, Santiago A.; Acosta, Andrés; Giménez, Patricia; Ocampo, Ligia; Leone, Paola E.Given the importance of mismatch repairing genes in keeping the genetic stability in cells, any alterations in their structure or function could generate instability in the genome and predispose the development of oncogenic processes. hMSH2 is the principal gene involved in the post-replicating DNA mismatch repair system. In this study, exon 13 of the hMSH2 gene was analyzed in different neoplasias, leukemias and lymphomas. The aim of our work was to determine the association between the presence of polymorphisms in this region with the development of alterations in the hematological system. The 227 samples including lymphoma, leukemia and myelodysplasic syndromes, where analyzed by PCR-SSCP followed by automated sequencing. A single nucleotide polymorphism was found in 30 individuals. This polymorphism is a T to C substitution at the -6 intronic splice acceptor site of exon 13 of hMSH2 gene [gIVS12-6T > C]. In the lymphoma group the polymorphism frequency found was 0.09, with statistical significant differences (p < 0.01) when compared to the control group. On the other hand, the frequency of the leukemia group was the same of that of the control group (0.05). These findings agree with previous research results of other investigation groups. The results suggest a probable association of the polymorphism with the development of lymphomas but not with leukemia.
- PublicationDosimetric effects of oral contrast in the planning of conventional radiotherapy and IMRT, for rectal cancer treatment(2022) Montero Oleas, Nadia; Imbaquingo Cabrera, Andrés; Coloma Espin, Alejandro; Collantes Cruz, Vladimir; Molineros Salgado, Carlos; Nuñez Silva, Cristinaoral contrast radiotherapy planning simulation tomography