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Many dominance relations have been established in the literature for scheduling problems where they are mainly used in implicit enumeration techniques to further reduce the search space for finding an optimal solution. In this paper, we propose a novel method for discovering dominance relations for scheduling problems. We discover dominance relations by using an evolutionary algorithm. The proposed method of empirically discovering dominance relations can be used for any scheduling problem. After the description of the method, we apply it to a specific scheduling problem. The specific problem is the multimedia data objects scheduling problem for WWW applications which can be modelled as the two-machine flowshop problem of minimizing maximum lateness with separate setup times. The performances of the dominance relations obtained by the proposed method as well as the existing four dominance relations in literature are analysed. The results of the computational experiments show that the proposed method is quite efficient. [ABSTRACT FROM AUTHOR]

The authors consider the multimedia object requests scheduling problem, an important problem in information systems such as World Wide Web applications. The problem can be modelled as a flowshop scheduling problem for which many solutions have been proposed with respect to different objective functions. This article considers the objective function of minimizing the variance of response time, which is crucial, as end users expect fair treatment of their service requests. This problem is known to be NP-hard, and therefore two heuristics to solve the problem have been proposed in the literature. This article presents a new heuristic that is shown to perform much better than the two existing ones; for example, the overall average error of the proposed heuristic has an improvement of about 500% and 1500% over the two existing ones. [ABSTRACT FROM AUTHOR]

Background: Travel burden has a substantial psychosocial impact and financial strain on childhood cancer patients and their families., Aims: To study the geographic distribution of childhood cancer and assess the travel burden for care in Saudi Arabia., Methods: This was a cross-sectional multi-institutional study that enrolled 1657 children with cancer who were diagnosed between 2011 and 2014. Cancer type/stage, city/region of residence, and city/region of treating centre were recorded. Travel burden was measured based on a 1-way distance in kilometres from the city centre to the treatment institution. This study was supported by Sanad Children's Cancer Support Association., Results: Diagnosis was leukaemia (45.2%), non-CNS solid tumours (30.2%), lymphoma (12.3%), CNS tumours (11.8%) and histiocytosis (0.5%). Childhood cancer centres were in the same city as where the patients lived in 652 (39.3%) cases, same region but different city in 308 (18.6%), different regions in 613 (37%), and not known in 84 (5.1%). The mean 1-way travel distance for patients who lived in different regions was 790 (range, 116-1542) km. A total of 536 (32%) patients lived ≥ 400 km and 216 (13%) > 1000 km from the treatment centre. Among 642 patients with acute lymphoblastic leukaemia who required 2-3 years of therapy, 197 (31%) lived ≥ 400 km and 94 (15%) >1000 km from the treatment centre., Conclusions: Nearly two thirds of patients with childhood cancer lived in different cities than the treatment centres, including one third of patients who lived ≥ 400 km away. There is a need to develop strategies to improve access to childhood cancer care., (Copyright © World Health Organization (WHO) 2020. Open Access. Some rights reserved. This work is available under the CC BY-NC-SA 3.0 IGO license (https://creativecommons.org/licenses/by-nc-sa/3.0/igo).)

Background: The frequency of pathogenic/likely pathogenic (P/LP) germline mutations in cancer-related genes among children with cancer in highly consanguineous populations is not well studied., Methods: Whole-exome sequencing of germline DNA was performed in 60 children with acute leukemia. We used the St. Jude Pediatric Cancer Variant Pathogenicity Information Exchange (PeCanPIE) data portal for the classification of germline variants by the St. Jude Medal Ceremony pipeline., Results: Fifty-seven patients had acute lymphoblastic leukemia (ALL) and three patients had acute myeloid leukemia. Parental consanguinity was present in 27 (45%) patients. All patients were of Arab ancestry. Three patients (5%) had a history of cancer in their siblings. Five patients (8.3%) had P/LP germline mutations in cancer-related genes. Three patients with B-ALL had heterozygous pathogenic mutations in TP53, BRCA1, and BRCA2; one patient with B-ALL had homozygous pathogenic mutation in PMS2; and one patient with T-ALL had LP homozygous mutation in AK2 that was associated with reticular dysgenesis. Among patients who had history of parental consanguinity, three (11%) had P/LP germline mutations compared with two (8%) in the absence of parental consanguinity. Fourteen (23%) patients had gold medal variants in cancer-related genes, 13 were heterozygous, and one was homozygous. Silver medal variants were present in 35 (58%) patients; all were heterozygous except one homozygous., Conclusions: Children with acute leukemia in Saudi Arabia had low frequency of P/LP mutations in cancer-related genes despite the high rate of consanguinity. Larger studies using whole-genome sequencing are needed to further explore the heritability of childhood leukemia., (© 2020 Wiley Periodicals, Inc.)

Background: The outcome of childhood acute myeloid leukemia (AML) in first relapse (rAML) remains poor. Reported overall survival (OS) rates vary between high-income developed countries and those with fewer resources. The OS of rAML in high-income developing countries (HIDCs) has not been reported., Patients and Materials: A multicenter study was performed in an HIDC. The outcome of patients with relapsed non-M3/non-Down syndrome AML was evaluated. Three-year OS was computed using the Kaplan-Meier method, and predictors of OS were analyzed using a Cox proportional hazards model., Results: A total of 88 patients with non-M3/non-Down syndrome AML diagnosed between January 2005 and December 2012 with a first relapse were identified. Their 3-year OS was 22.6% ± 5.4%. Patients with inv(16) and t(8;21) had an OS of 75.0% ± 21.7% and 36.0% ± 16.1%, respectively. Worse outcomes were associated with "other intermediate" and 11q23 rearrangement AML (OS of 9.4% ± 8.7% and 10.7% ± 9.6%, respectively). Patients experiencing time to relapse (TTR) less than 1 year had shorter OS than those with a longer TTR (14.6% ± 5.4% vs. 41.1% ± 11.5%; P = .006). The outcome of patients after stem cell transplantation (SCT) in second complete remission (CR2) was superior compared with no SCT (50.9% ± 11.2% vs. 7.7% ± 4.6%; P = .001). TTR, risk group, CR2, and SCT in CR2 were the most significant predictors for survival., Conclusions: rAML remains a clinical challenge. Genetic variability in outcomes was observed. A majority of patients with inv(16) were successfully salvaged post-relapse, whereas patients with 11q23 rearrangement had a poor prognosis. Only one-third of those with t(8;21) rAML survived. Better access to SCT in HIDCs is needed., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background & Aim: Hereditary cancer susceptibility syndromes (HCSS) are reported in up to one-third of children with cancer. Diagnosis of HCSS is crucial for implementation of surveillance protocols. We identified children who fulfilled criteria for HCSS in Saudi Arabia using the American College of Medical Genetics and Genomics (ACMG) guidelines, addressing the utility of these guidelines in a highly consanguineous population., Methods: This multi-center cross-sectional study recruited 1858 children with cancer between January 2011 and December 2014. HCSS criteria were based on the ACMG guidelines., Results: Seven hundred and four (40.4%) out of 1742 eligible patients fulfilled criteria for HCSS. Consanguinity was reported in 629 (38%) patients, with 50 (2.9%) first-degree, 535 (30.7%) second-degree, and 272 (15.6%) third-degree relatives affected with cancer. Two hundred and eighty eight (17.4%) leukemia and 87 (5.3%) brain tumour patients fulfilled HCSS criteria, with parental consanguinity being the most frequent criterion in both (leukemia 85.4%, brain tumors 83.9%). However, leukemia was less frequent in patients of consanguineous parents (p = 0.023)., Conclusion: Four out of 10 children with cancer fulfilled criteria for HCSS, most often due to consanguinity. This higher than expected prevalence suggests the need to validate consanguinity as a criterion for HCSS in highly consanguineous populations., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Acute promyelocytic leukemia (APL) is a rare form of acute myelogenous leukemia (AML). Survival rates exceed 80% in developed countries. Successful treatments rely on all-trans retinoic acid with anthracycline-based chemotherapy. Availability of modern care and public knowledge play important roles in pediatric APL survival., Method: A cytogenetic diagnosis of APL was confirmed in 30 (14.5%) out of 207 children consecutively diagnosed with de novo AML between January 2005 and December 2012 at nine cancer care centers in Saudi Arabia. Patients were treated based on the standard protocol used by the center following the PETHEMA or the C9710 treatment protocols. We modeled 5-year overall survival (OS), event-free survival (EFS) and cumulative incidence of relapse (CIR) vs. treatment and potential covariates of age at diagnosis, involvement of central nervous system (CNS), and white blood cell (WBC) levels., Results: The median age was 10.4 years with a male:female ratio of 1.9. WBC was 10 × 10 9 /l or greater in 57% and CNS involvement was confirmed in 13%. OS, EFS, and CIR were 74 ± 12%, 55 ± 19%, and, 36 ± 17% respectively. No significant difference was found by treatment protocol. WBC levels were significantly prognostic for all negative events, but treatment with C9710 significantly ameliorated negative WBC effects. Overall outcomes were comparable to those reported in developed countries., Conclusions: Access to modern care is likely to be a critical factor in successful and comparable outcomes of childhood APL across the globe. In the present study, utilizing a cytarabine-containing protocol improved outcome of high-risk pediatric patients with APL.

Despite the high incidence of Down syndrome (DS) in Arab countires, the incidence and outcomes of myeloid leukemia of DS (ML-DS) have not been studied. We evaluated 206 pediatric acute myeloid leukemia (AML) patients diagnosed between 2005 and 2012 and identified 31 (15%) ML-DS. The incidence of ML-DS was 48 per 100,000 compared to 0.6 per 100,000 for AML in non-DS children. Thus, patients with DS had 80-fold increased risk of ML-DS compared to AML in non-DS children. The median age at diagnosis was 1.8 years, male/female ratio was 1.2, majority (84%) of patients had FAB-M7 subtype, and the cytogenetic abnormalities were normal karyotype (constitutional trisomy 21) in 48%, additional trisomy in 23%, and other aberrations in 29%. Complete remission, cumulative incidences of relapse (CIR), toxic-death, and 5-year event-free survival (EFS) rates were 96.8%, 19.4%, 13.1%, and 67.7±8.4%; respectively. In the present study, multivariate analysis revealed favorable outcome (5-year EFS 86.7±8.8%) for patients with normal karyotype. The incidence and clinical characteristics of ML-DS in Saudi patients were comparable to other reports. However, there is a need to optimize risk stratification and treatment intensity to reduce CIR and toxic death rates to further improve outcomes of patients with ML-DS., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Geographic variation and ethnicity have been implicated to influence the outcome of pediatric acute myeloid leukemia (AML). Furthermore, survival outcomes from developing countries are reported to be inferior to developed nations. We hypothesized that risk- and response-based outcome in high-income resource-rich developing countries would be comparable to developed nations as access to care and supportive measures would be similar. A total of 193 children diagnosed with de novo AML between January 2005 and December 2012 were identified, of those 175 were evaluable for outcome. Patients were stratified into low-risk (LR), intermediate-risk (IR), or high-risk (HR) groups. The complete remission (CR), early death, and induction failure rates were: 85.7%, 2.3%, and 12%; respectively. The 5-year cumulative incidences of relapse (CIR) and non-relapse mortality (NRM) were 43.1% and 9.8% respectively; overall survival (OS) was 58.8±4% and event-free survival (EFS) 40.9±4.1%. The 5-year OS for LR, IR, and HR groups were 72.0±6.9%, 59.8±6.2%, and 45.1±7.4%; respectively (p=0.003); and EFS 50.5±8.0%, 46.3±6.4%, and 23.3±6.4%; respectively (p=0.001). This study demonstrated comparable outcomes to those reported from developed countries. This suggests that utilization of risk- and response-based protocols in developing countries can overcome ethnic and geographic variation, if access to care and supportive measures were similar., (Copyright © 2016 Elsevier Ltd. All rights reserved.)