ORCID Profile
0000-0002-9762-6901
Current Organisations
Hospital for Sick Children
,
Princess Margaret Cancer Centre
,
University of Toronto
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Publisher: Oxford University Press (OUP)
Date: 20-01-2020
DOI: 10.1093/NOP/NPZ072
Abstract: Radiation necrosis is a frequent complication occurring after the treatment of pediatric brain tumors however, treatment options remain a challenge. Bevacizumab is an anti-VEGF monoclonal antibody that has been shown in small adult cohorts to confer a benefit, specifically a reduction in steroid usage, but its use in children has not been well described. We describe our experience with bevacizumab use for symptomatic radiation necrosis at 5 institutions including patients treated after both initial irradiation and reirradiation. We identified 26 patients treated with bevacizumab for symptomatic radiation necrosis, with a wide range of underlying diagnoses. The average age at diagnosis of radiation necrosis was 10.7 years, with a median time between the last dose of radiation and the presentation of radiation necrosis of 3.8 months (range, 0.6-110 months). Overall, we observed that 13 of 26 patients (50%) had an objective clinical improvement, with only 1 patient suffering from significant hypertension. Radiological improvement, defined as reduced T2/fluid-attenuated inversion recovery signal and mass effect, was observed in 50% of patients however, this did not completely overlap with clinical response. Both early and late radiation necrosis responded equally well to bevacizumab therapy. Overall, bevacizumab was very well tolerated, permitting a reduction of corticosteroid dose and/or duration in the majority of patients. Bevacizumab appears to be effective and well-tolerated in children as treatment for symptomatic radiation necrosis and warrants more robust study in the context of controlled clinical trials.
Publisher: American Association for Cancer Research (AACR)
Date: 12-10-2023
Publisher: Elsevier BV
Date: 11-2021
Publisher: Elsevier BV
Date: 02-2021
Publisher: Frontiers Media SA
Date: 22-12-2020
Abstract: Primary CNS tumors are the leading cause of cancer-related death in pediatrics. It is essential to understand treatment trends to interpret national survival data. In Canada, children with CNS tumors are treated at one of 16 tertiary care centers. We surveyed pediatric neuro-oncologists to create a national standard of practice to be used in the absence of a clinical trial for seven of the most prevalent brain tumors in children. This allowed description of practice across the country, along with a consensus. This had a multitude of benefits, including understanding practice patterns, allowing for a basis to compare in future research and informing Health Canada of the current management of patients. This also allows all children in Canada to receive equivalent care, regardless of location.
Publisher: Springer Science and Business Media LLC
Date: 2022
DOI: 10.1038/S41591-021-01581-6
Abstract: Cancers arising from germline DNA mismatch repair deficiency or polymerase proofreading deficiency (MMRD and PPD) in children harbour the highest mutational and microsatellite insertion–deletion (MS-indel) burden in humans. MMRD and PPD cancers are commonly lethal due to the inherent resistance to chemo-irradiation. Although immune checkpoint inhibitors (ICIs) have failed to benefit children in previous studies, we hypothesized that hypermutation caused by MMRD and PPD will improve outcomes following ICI treatment in these patients. Using an international consortium registry study, we report on the ICI treatment of 45 progressive or recurrent tumors from 38 patients. Durable objective responses were observed in most patients, culminating in a 3 year survival of 41.4%. High mutation burden predicted response for ultra-hypermutant cancers ( mutations per Mb) enriched for combined MMRD + PPD, while MS-indels predicted response in MMRD tumors with lower mutation burden (10–100 mutations per Mb). Furthermore, both mechanisms were associated with increased immune infiltration even in ‘immunologically cold’ tumors such as gliomas, contributing to the favorable response. Pseudo-progression (flare) was common and was associated with immune activation in the tumor microenvironment and systemically. Furthermore, patients with flare who continued ICI treatment achieved durable responses. This study demonstrates improved survival for patients with tumors not previously known to respond to ICI treatment, including central nervous system and synchronous cancers, and identifies the dual roles of mutation burden and MS-indels in predicting sustained response to immunotherapy.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 18-05-2021
DOI: 10.1097/ANA.0000000000000778
Abstract: High-grade gliomas impose substantial morbidity and mortality due to rapid cancer progression and recurrence. Factors such as surgery, chemotherapy and radiotherapy remain the cornerstones for treatment of brain cancer and brain cancer research. The role of anesthetics on glioma progression is largely unknown. This multicenter retrospective cohort study compared patients who underwent high-grade glioma resection with minimal sedation (awake craniotomy) and those who underwent craniotomy with general anesthesia (GA). Various perioperative factors, intraoperative and postoperative complications, and adjuvant treatment regimens were recorded. The primary outcome was progression-free survival (PFS) secondary outcomes were overall survival (OS), postoperative pain score, and length of hospital stay. A total of 891 patients were included 79% received GA, and 21% underwent awake craniotomy. There was no difference in median PFS between awake craniotomy (0.54, 95% confidence interval [CI]: 0.45-0.65 y) and GA (0.53, 95% CI: 0.48-0.60 y) groups (hazard ratio 1.05 P .553). Median OS was significantly longer in the awake craniotomy (1.70, 95% CI: 1.30-2.32 y) compared with that in the GA (1.25, 95% CI: 1.15-1.37 y) group (hazard ratio 0.76 P .009) but this effect did not persist after controlling for other variables of interest. Median length of hospital stay was significantly shorter in the awake craniotomy group (2 [range: 0 to 76], interquartile range 3 d vs. 5 [0 to 98], interquartile range 5 for awake craniotomy and GA groups, respectively P .001). Pain scores were comparable between groups. There was no difference in PFS and OS between patients who underwent surgical resection of high-grade glioma with minimal sedation (awake craniotomy) or GA. Further large prospective randomized controlled studies are needed to explore the role of anesthetics on glioma progression and patient survival.
Publisher: American Society of Clinical Oncology (ASCO)
Date: 04-2023
DOI: 10.1200/JCO.21.02968
Abstract: Infant and young childhood medulloblastoma (iMB) is usually treated without craniospinal irradiation (CSI) to avoid neurocognitive late effects. Unfortunately, many children relapse. The purpose of this study was to assess salvage strategies and prognostic features of patients with iMB who relapse after CSI-sparing therapy. We assembled a large international cohort of 380 patients with relapsed iMB, age younger than 6 years, and initially treated without CSI. Univariable and multivariable Cox models of postrelapse survival (PRS) were conducted for those treated with curative intent using propensity score analyses to account for confounding factors. The 3-year PRS, for 294 patients treated with curative intent, was 52.4% (95% CI, 46.4 to 58.3) with a median time to relapse from diagnosis of 11 months. Molecular subgrouping was available for 150 patients treated with curative intent, and 3-year PRS for sonic hedgehog (SHH), group 4, and group 3 were 60%, 84%, and 18% ( P = .0187), respectively. In multivariable analysis, localized relapse ( P = .0073), SHH molecular subgroup ( P = .0103), CSI use after relapse ( P = .0161), and age ≥ 36 months at initial diagnosis ( P = .0494) were associated with improved survival. Most patients (73%) received salvage CSI, and although salvage chemotherapy was not significant in multivariable analysis, its use might be beneficial for a subset of children receiving salvage CSI 35 Gy ( P = .007). A substantial proportion of patients with relapsed iMB are salvaged after initial CSI-sparing approaches. Patients with SHH subgroup, localized relapse, older age at initial diagnosis, and those receiving salvage CSI show improved PRS. Future prospective studies should investigate optimal CSI doses and the role of salvage chemotherapy in this population.
Publisher: Research Square Platform LLC
Date: 15-02-2021
DOI: 10.21203/RS.3.RS-155292/V1
Abstract: Cancers arising from germline DNA mismatch-repair or polymerase-proofreading deficiencies (MMRD and PPD) in children harbour the highest mutational and microsatellite insertion/deletion (MS-indel) burden in humans and are lethal due to inherent resistance to chemo-irradiation. Although immune checkpoint inhibitors (ICI) have failed to benefit children in previous studies, we hypothesized that hypermutation caused by MMRD and PPD will improve outcomes following ICI in these patients. ICI treatment of 45 progressive/recurrent tumours from 38 patients revealed durable objective responses in the majority, culminating in 3-year survival of 41.4%. High mutation burden predicted response for ultra-hypermutant cancers ( mutations/Mb) enriched for combined MMRD+PPD, while MS-indels predicted response in MMRD tumours with lower mutation burden (10-100 mutations/Mb). Further, both mechanisms were associated with increased immune infiltration even in “immunologically-cold” tumours such as gliomas, contributing to the favorable response. Pseudo-progression (flare) was common and associated with immune activation in both the tumour microenvironment and systemically. Further, patients with flare continuing ICI treatment achieved durable responses. Our study demonstrates improved survival for patients with tumours not previously known to respond to ICI, including CNS and synchronous cancers, and identifies the dual roles of mutation burden and MS-indels in predicting sustained responses to immunotherapy.
Location: United States of America
No related grants have been discovered for Derek Tsang.