Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Brian O'Sullivan is active.

Publication


Featured researches published by Brian O'Sullivan.


The Lancet | 2002

Preoperative versus postoperative radiotherapy in soft-tissue sarcoma of the limbs: a randomised trial

Brian O'Sullivan; Aileen M. Davis; Robert Turcotte; Charles Catton; Pierre Chabot; Jay S. Wunder; Rita A. Kandel; Karen Goddard; Anna Sadura; Joseph L. Pater; Benny Zee

BACKGROUND External-beam radiotherapy (delivered either preoperatively or postoperatively) is frequently used in local management of sarcomas in the soft tissue of limbs, but the two approaches differ substantially in their potential toxic effects. We aimed to determine whether the timing of external-beam radiotherapy affected the number of wound healing complications in soft-tissue sarcoma in the limbs of adults. METHODS After stratification by tumour size (< or = 10 cm or >10 cm), we randomly allocated 94 patients to preoperative radiotherapy (50 Gy in 25 fractions) and 96 to postoperative radiotherapy (66 Gy in 33 fractions). The primary endpoint was rate of wound complications within 120 days of surgery. Analyses were per protocol for primary outcomes and by intention to treat for secondary outcomes. FINDINGS Median follow-up was 3.3 years (range 0.27-5.6). Four patients, all in the preoperative group, did not undergo protocol surgery and were not evaluable for the primary outcome. Of those patients who were eligible and evaluable, wound complications were recorded in 31 (35%) of 88 in the preoperative group and 16 (17%) of 94 in the postoperative group (difference 18% [95% CI 5-30], p=0.01). Tumour size and anatomical site were also significant risk factors in multivariate analysis. Overall survival was slightly better in patients who had preoperative radiotherapy than in those who had postoperative treatment (p=0.0481). INTERPRETATION Because preoperative radiotherapy is associated with a greater risk of wound complications than postoperative radiotherapy, the choice of regimen for patients with soft-tissue sarcoma should take into account the timing of surgery and radiotherapy, and the size and anatomical site of the tumour.


The Lancet | 2006

Hyperfractionated or accelerated radiotherapy in head and neck cancer: a meta-analysis

Jean Bourhis; Jens Overgaard; Hélène Audry; K.K. Ang; M.I. Saunders; Jacques Bernier; Jean-Claude Horiot; Aurélie Le Maître; Thomas F. Pajak; Michael G Poulsen; Brian O'Sullivan; Werner Dobrowsky; Andrzej Hliniak; K. Składowski; John Hay; Luiz H. J. Pinto; Carlo Fallai; Karen K. Fu; Richard Sylvester; Jean-Pierre Pignon

BACKGROUND Several trials have studied the role of unconventional fractionated radiotherapy in head and neck squamous cell carcinoma, but the effect of such treatment on survival is not clear. The aim of this meta-analysis was to assess whether this type of radiotherapy could improve survival. METHODS Randomised trials comparing conventional radiotherapy with hyperfractionated or accelerated radiotherapy, or both, in patients with non-metastatic HNSCC were identified and updated individual patient data were obtained. Overall survival was the main endpoint. Trials were grouped in three pre-specified categories: hyperfractionated, accelerated, and accelerated with total dose reduction. FINDINGS 15 trials with 6515 patients were included. The median follow-up was 6 years. Tumours sites were mostly oropharynx and larynx; 5221 (74%) patients had stage III-IV disease (International Union Against Cancer, 1987). There was a significant survival benefit with altered fractionated radiotherapy, corresponding to an absolute benefit of 3.4% at 5 years (hazard ratio 0.92, 95% CI 0.86-0.97; p=0.003). The benefit was significantly higher with hyperfractionated radiotherapy (8% at 5 years) than with accelerated radiotherapy (2% with accelerated fractionation without total dose reduction and 1.7% with total dose reduction at 5 years, p=0.02). There was a benefit on locoregional control in favour of altered fractionation versus conventional radiotherapy (6.4% at 5 years; p<0.0001), which was particularly efficient in reducing local failure, whereas the benefit on nodal control was less pronounced. The benefit was significantly higher in the youngest patients (hazard ratio 0.78 [0.65-0.94] for under 50 year olds, 0.95 [0.83-1.09] for 51-60 year olds, 0.92 [0.81-1.06] for 61-70 year olds, and 1.08 [0.89-1.30] for over 70 year olds; test for trends p=0.007). INTERPRETATION Altered fractionated radiotherapy improves survival in patients with head and neck squamous cell carcinoma. Comparison of the different types of altered radiotherapy suggests that hyperfractionation has the greatest benefit.


Journal of Clinical Oncology | 2010

Prognostic Significance of p16INK4A and Human Papillomavirus in Patients With Oropharyngeal Cancer Treated on TROG 02.02 Phase III Trial

Danny Rischin; Richard J. Young; Richard Fisher; Stephen B. Fox; Quynh-Thu Le; Lester J. Peters; Ben Solomon; Jimin Choi; Brian O'Sullivan; Lizbeth Kenny; Grant A. McArthur

PURPOSE To determine the prognostic importance of p16 and human papillomavirus (HPV) in patients with oropharyngeal cancer treated on a phase III concurrent chemoradiotherapy trial. PATIENTS AND METHODS Patients with stage III or IV head and neck squamous cell cancer were randomly assigned to concurrent radiotherapy and cisplatin with or without tirapazamine. In this substudy, analyses were restricted to patients with oropharyngeal cancer. p16 was detected by immunohistochemistry, and HPV was detected by in situ hybridization and polymerase chain reaction. RESULTS Slides were available for p16 assay in 206 of 465 patients, of which 185 were eligible, and p16 and HPV were evaluable in 172 patients. One hundred six (57%) of 185 were p16-positive, and in patients evaluable for both p16 and HPV, 88 (86%) of 102 p16-positive patients were also HPV-positive. Patients who were p16-positive had lower T and higher N categories and better Eastern Cooperative Oncology Group (ECOG) performance status. p16-positive tumors compared with p16-negative tumors were associated with better 2-year overall survival (91% v 74%; hazard ratio [HR], 0.36; 95% CI, 0.17 to 0.74; P = .004) and failure-free survival (87% v 72%; HR, 0.39; 95% CI, 0.20 to 0.74; P = .003). p16 was a significant prognostic factor on multivariable analysis (HR, 0.45; 95% CI, 0.21 to 0.96; P = .04). p16-positive patients had lower rates of locoregional failure and deaths due to other causes. There was a trend favoring the tirapazamine arm for improved locoregional control in p16-negative patients (HR, 0.33; 95% CI, 0.09 to 1.24; P = .13). CONCLUSION HPV-associated oropharyngeal cancer is a distinct entity with a favorable prognosis compared with HPV-negative oropharyngeal cancer when treated with cisplatin-based chemoradiotherapy.


Journal of Clinical Oncology | 2010

Critical Impact of Radiotherapy Protocol Compliance and Quality in the Treatment of Advanced Head and Neck Cancer: Results From TROG 02.02

Lester J. Peters; Brian O'Sullivan; Jordi Giralt; Thomas J. Fitzgerald; Andy Trotti; Jacques Bernier; Jean Bourhis; Kally Yuen; Richard Fisher; Danny Rischin

PURPOSE To report the impact of radiotherapy quality on outcome in a large international phase III trial evaluating radiotherapy with concurrent cisplatin plus tirapazamine for advanced head and neck cancer. PATIENTS AND METHODS The protocol required interventional review of radiotherapy plans by the Quality Assurance Review Center (QARC). All plans and radiotherapy documentation underwent post-treatment review by the Trial Management Committee (TMC) for protocol compliance. Secondary review of noncompliant plans for predicted impact on tumor control was performed. Factors associated with poor protocol compliance were studied, and outcome data were analyzed in relation to protocol compliance and radiotherapy quality. RESULTS At TMC review, 25.4% of the patients had noncompliant plans but none in which QARC-recommended changes had been made. At secondary review, 47% of noncompliant plans (12% overall) had deficiencies with a predicted major adverse impact on tumor control. Major deficiencies were unrelated to tumor subsite or to T or N stage (if N+), but were highly correlated with number of patients enrolled at the treatment center (< five patients, 29.8%; > or = 20 patients, 5.4%; P < .001). In patients who received at least 60 Gy, those with major deficiencies in their treatment plans (n = 87) had a markedly inferior outcome compared with those whose treatment was initially protocol compliant (n = 502): -2 years overall survival, 50% v 70%; hazard ratio (HR), 1.99; P < .001; and 2 years freedom from locoregional failure, 54% v 78%; HR, 2.37; P < .001, respectively. CONCLUSION These results demonstrate the critical importance of radiotherapy quality on outcome of chemoradiotherapy in head and neck cancer. Centers treating only a few patients are the major source of quality problems.


Journal of Clinical Oncology | 2013

Deintensification Candidate Subgroups in Human Papillomavirus-Related Oropharyngeal Cancer According to Minimal Risk of Distant Metastasis

Brian O'Sullivan; Shao Hui Huang; Lillian L. Siu; John Waldron; Helen Zhao; Bayardo Perez-Ordonez; Ilan Weinreb; John Kim; Jolie Ringash; A. Bayley; Laura A. Dawson; Andrew Hope; J. Cho; Jonathan M. Irish; Ralph W. Gilbert; Patrick J. Gullane; Angela Hui; Fei-Fei Liu; Eric X. Chen; Wei Xu

PURPOSE To define human papillomavirus (HPV) -positive oropharyngeal cancers (OPC) suitable for treatment deintensification according to low risk of distant metastasis (DM). PATIENTS AND METHODS OPC treated with radiotherapy (RT) or chemoradiotherapy (CRT) from 2001 to 2009 were included. Outcomes were compared for HPV-positive versus HPV-negative patients. Univariate and multivariate analyses identified outcome predictors. Recursive partitioning analysis (RPA) stratified the DM risk. RESULTS HPV status was ascertained in 505 (56%) of 899 consecutive OPCs. Median follow-up was 3.9 years. HPV-positive patients (n = 382), compared with HPV-negative patients (n = 123), had higher local (94% v 80%, respectively, at 3 years; P < .01) and regional control (95% v 82%, respectively; P < .01) but similar distant control (DC; 90% v 86%, respectively; P = .53). Multivariate analysis identified that HPV negativity (hazard ratio [HR], 2.9; 95% CI, 2.0 to 5.0), N2b-N3 (HR, 2.9; 95% CI, 1.8 to 4.9), T4 (HR, 1.8; 95% CI, 1.2 to 2.9), and RT alone (HR, 1.8; 95% CI, 1.1 to 2.5) predicted a lower recurrence-free survival (RFS; all P < .01). Smoking pack-years > 10 reduced overall survival (HR, 1.72; 95% CI, 1.1 to 2.7; P = .03) but did not impact RFS (HR, 1.1; 95% CI, 0.7 to 1.9; P = .65). RPA segregated HPV-positive patients into low (T1-3N0-2c; DC, 93%) and high DM risk (N3 or T4; DC, 76%) groups and HPV-negative patients into different low (T1-2N0-2c; DC, 93%) and high DM risk (T3-4N3; DC, 72%) groups. The DC rates for HPV-positive, low-risk N0-2a or less than 10 pack-year N2b patients were similar for RT alone and CRT, but the rate was lower in the N2c subset managed by RT alone (73% v 92% for CRT; P = .02). CONCLUSION HPV-positive T1-3N0-2c patients have a low DM risk, but N2c patients from this group have a reduced DC when treated with RT alone and seem less suited for deintensification strategies that omit chemotherapy.


Radiotherapy and Oncology | 1996

Chordoma: long-term follow-up after radical photon irradiation

Charles Catton; Brian O'Sullivan; Normand Laperriere; Bernard Cummings; Victor Fornasier; Jay S. Wunder

PURPOSE To retrospectively analyze the long term results of treatment and the patterns of failure for patients with chordoma of the sacrum, base of skull and mobile spine treated predominantly with postoperative photon irradiation. MATERIALS AND METHODS Forty-eight adult patients with chordoma of the sacrum (23), base of skull (20) or mobile spine (5), were seen between 1958-1992. Forty-four were referred post operatively with overt disease and 31 of these were irradiated with conventionally fractionated radiation to a median dose of 50 Gy/25 fractions/5 weeks (range 25-60 Gy). Eight received a hyperfractionation protocol of 1 Gy, 4 hourly, 4 times a day (median 40 Gy/44 fractions/14 days), two sacral patients were treated with a hypofractionation protocol and three cases with skull base tumours were referred elsewhere for proton therapy. Endpoints measured were survival from diagnosis, objective response rate, symptomatic response rate and clinical or radiological progression-free survival from radiotherapy. RESULTS Median survival was 62 months (range 4-240 month) from diagnosis with no difference between clival and non-clival presentations. One complete and no partial responses were identified in 23 assessable patients. A subjective response was recorded for 12/14 (85%) with pain and 10/23 (45%) with neurological signs or symptoms, and the median time to progression for those with overt disease was 35 months (range 5-220 months). There was no survival advantage to patients receiving radiation doses > 50 Gy (median 60 Gy) compared to doses < 50 Gy (median 40 Gy). There was no difference between the conventional or hyperfractionation regimens with respect to the degree or duration of symptomatic response, or in progression-free survival. Fourteen patients who progressed after irradiation were retreated with surgery (6), irradiation (7) or both modalities (1). Median survival after retreatment was 18 months, and the only two symptomatic responses seen were with reirradiation, and after failure of relatively low dose initial therapy. At last follow-up, 35 were dead of or with disease, seven are alive with disease, and two are disease-free. Thirty-eight had local disease persistence as the sole site of failure, and four developed distant metastases initially or subsequently. DISCUSSION Overt residual chordoma is rarely cured with conventional external beam irradiation, but treatment does provide useful and prolonged palliation of pain for most patients. Chordoma is a disease with low metastatic potential, and better local control may improve survival. Complete resection rates may be improved for patients with sacral disease by using planned excisions in centres experienced in treating this rare disease. Because radiation therapy may prove to be more successful in controlling microscopic disease, it should be considered as a pre- or postoperative adjuvant to a macroscopically complete resection. Patients with skull base disease should also be resected in centres specializing in this surgery, but complete excision is unlikely. These patients will not obtain local control with conventional photon irradiation, and suitable patients should be considered for irradiation with stereotactic photon or particle beam therapy. For patients who progress after irradiation, there is limited symptomatic benefit to retreatment with surgery or reirradiation, and this should be limited to treating life-threatening complications.


Journal of Clinical Oncology | 2005

Preliminary Results of a Randomized Study on Therapeutic Gain by Concurrent Chemotherapy for Regionally-Advanced Nasopharyngeal Carcinoma: NPC-9901 Trial by the Hong Kong Nasopharyngeal Cancer Study Group

Anne W.M. Lee; W. H. Lau; Stewart Y. Tung; Daniel T.T. Chua; Rick Chappell; L. Xu; Lillian L. Siu; W.M. Sze; To-Wai Leung; Jonathan S. T. Sham; Roger K.C. Ngan; Stephen C.K. Law; T.K. Yau; Joseph Sk Au; Brian O'Sullivan; Ellie S.Y. Pang; Gordon K.H. Au; Joseph Lau

PURPOSE This randomized study compared the results achieved by concurrent chemoradiotherapy (CRT) versus radiotherapy (RT) alone for nasopharyngeal carcinoma (NPC) with advanced nodal disease. PATIENTS AND METHODS Patients with nonkeratinizing/undifferentiated NPC staged T1-4N2-3M0 were randomized to CRT or RT. Both arms were treated with the same RT technique and dose fractionation. The CRT patients were given cisplatin 100 mg/m2 on days 1, 22, and 43, followed by cisplatin 80 mg/m2 and fluorouracil 1,000 mg/m2/d for 96 hours starting on days 71, 99, and 127. RESULTS From 1999 to January 2004, 348 eligible patients were randomly assigned; the median follow-up was 2.3 years. The two arms were well-balanced in all prognostic factors and RT parameters. The CRT arm achieved significantly higher failure-free survival (72% v 62% at 3-year, P = .027), mostly as a result of an improvement in locoregional control (92% v 82%, P = .005). However, distant control did not improve significantly (76% v 73%, P = .47), and the overall survival rates were almost identical (78% v 78%, P = .97). In addition, the CRT arm had significantly more acute toxicities (84% v 53%, P < .001) and late toxicities (28% v 13% at 3-year, P = .024). CONCLUSION Preliminary results confirmed that CRT could significantly improve tumor control, particularly at locoregional sites. However, there was significant increase in the risk of toxicities and no early gain in overall survival. Longer follow-up is needed to confirm the ultimate therapeutic ratio.


Journal of Clinical Oncology | 2009

Comparative Prognostic Value of HPV16 E6 mRNA Compared With In Situ Hybridization for Human Oropharyngeal Squamous Carcinoma

Wei Shi; Hisayuki Kato; Bayardo Perez-Ordonez; Melania Pintilie; Shao‐Hui Huang; Angela Hui; Brian O'Sullivan; John Waldron; Bernard Cummings; John Kim; Jolie Ringash; Laura A. Dawson; Patrick J. Gullane; Lillian L. Siu; Maura L. Gillison; Fei-Fei Liu

PURPOSE A significant proportion of oropharyngeal squamous cell carcinomas (OSCC) are associated with the human papilloma virus (HPV), particularly HPV16. The optimal method for HPV determination on archival materials however, remains unclear. We compared a quantitative real-time polymerase chain reaction (qRT-PCR) assay for HPV16 mRNA to a DNA in situ hybridization (ISH) method, and evaluated their significance for overall (OS) and disease-free (DFS) survival. PATIENTS AND METHODS Matched, archival biopsies from 111 patients with OSCC were evaluated for HPV16 using a qRT-PCR for E6 mRNA and ISH for DNA. Immunohistochemistry for p16, p53, and epidermal growth factor receptor were also performed. RESULTS HPV16 E6 mRNA was positive in 73 (66%) of 111 samples; ISH was positive in 62 of 106 samples (58%), with 86% concordance. P16 was overexpressed in 72 samples (65%), which was strongly associated with HPV16 status by either method. E6 mRNA presence or p16 overexpression were significantly associated with superior OS; E6 mRNA, HPV16 ISH, or p16 were all significantly associated with DFS. On multivariate analysis adjusted for age, stage, and treatment, positive E6 mRNA was the only independent predictor for superior OS; for DFS, p16 expression or HPV16 status determined by either method was significant. CONCLUSION The prevalence of HPV16 in OSCC ranges from 58% to 66%, in a recently treated Canadian cohort. Classification of HPV-positivity by HPV16 E6 mRNA, HPV16 ISH or p16 immunohistochemistry (IHC) is associated with improved DFS. However, the latter two assays are technically easier to perform; hence, HPV16 ISH or p16 IHC should become standard evaluations for all patients with OSCC.


Journal of Clinical Oncology | 2010

Tirapazamine, Cisplatin, and Radiation Versus Cisplatin and Radiation for Advanced Squamous Cell Carcinoma of the Head and Neck (TROG 02.02, HeadSTART): A Phase III Trial of the Trans-Tasman Radiation Oncology Group

Danny Rischin; Lester J. Peters; Brian O'Sullivan; Jordi Giralt; Richard Fisher; Kally Yuen; Andy Trotti; Jacques Bernier; Jean Bourhis; Jolie Ringash; Michael Henke; Lizbeth Kenny

PURPOSE Promising results in a randomized phase II trial with the hypoxic cytotoxin tirapazamine (TPZ) combined with cisplatin (CIS) and radiation led to this phase III trial. PATIENTS AND METHODS Patients with previously untreated stage III or IV (excluding T1-2N1 and M1) squamous cell carcinoma of the oral cavity, oropharynx, hypopharynx, or larynx were randomly assigned to receive definitive radiotherapy (70 Gy in 7 weeks) concurrently with either CIS (100 mg/m(2)) on day 1 of weeks 1, 4, and 7 or CIS (75 mg/m(2)) plus TPZ (290 mg/m(2)/d) on day 1 of weeks 1, 4, and 7 and TPZ alone (160 mg/m(2)/d) on days 1, 3, and 5 of weeks 2 and 3 (TPZ/CIS). The primary end point was overall survival (OS). The planned sample size was 850, estimated to result in 334 deaths, which would provide 90% power to detect a difference in 2-year survival rates of 60% v 70% for CIS versus TPZ/CIS, respectively (hazard ratio = 0.69). RESULTS Eight hundred sixty-one patients were accrued from 89 sites in 16 countries. In an intent-to-treat analysis, the 2-year OS rates were 65.7% for CIS and 66.2% for TPZ/CIS (TPZ/CIS--CIS: 95% CI, -5.9% to 6.9%). There were no significant differences in failure-free survival, time to locoregional failure, or quality of life as measured by Functional Assessment of Cancer Therapy-Head and Neck. CONCLUSIONS We found no evidence that the addition of TPZ to chemoradiotherapy, in patients with advanced head and neck cancer not selected for the presence of hypoxia, improves OS.


International Journal of Radiation Oncology Biology Physics | 1993

Outcome and prognosis in retroperitoneal soft tissue sarcoma

Charles Catton; Brian O'Sullivan; Cyrus Kotwall; Bernard Cummings; Yong Hao; Victor Fornasier

PURPOSE To retrospectively evaluate the outcome of treatment and identify factors prognostic for survival and locoregional and distant disease control for patients with retroperitoneal soft tissue sarcoma. METHODS AND MATERIALS The records of 104 patients with retroperitoneal soft tissue sarcoma (RSTS) managed with surgery and irradiation at Princess Margaret Hospital between 1975 and 1988 were retrospectively reviewed. Univariate log-rank analysis was used to evaluate potential prognostic factors. RESULTS Presentation was new primary disease, 74; primary recurrence, 20; metastases, 10. Pathology was liposarcoma for 42, leiomyosarcoma for 22, malignant fibrous histiocytoma for 19, and 21 with other histologies. Grade was low for 36, high for 35, and 33 were not graded. Median tumor size was 17 cm. Grossly complete surgical excision was achieved for 45 (43%), of whom 6 (6%) also had clear surgical margins. Adjuvant postoperative irradiation was administered to 36 patients to a median dose of 40 Gy/20 fractions/4 weeks and 16 received adjuvant chemotherapy. Nine patients received no adjuvant postoperative radiotherapy. Gross residual tumor was present postoperatively in 57 patients. The overall 5- and 10-year survival rates were 36% and 14%, respectively. The locoregional relapse free rate (RFR) was 28% at 5 years and 9% at 10 years, and the distant RFR was 76% at 5 years and 60% at 10 years. For the 45 patients treated with complete excision, survival was 55% and 22% at 5 and 10 years, and locoregional RFR was 50% and 18% at 5 and 10 years. Univariate analysis demonstrated that complete surgical removal was the only factor significant for improved survival, locoregional RFR, and distant RFR. Liposarcoma histology predicted for improved survival (p = 0.02), and leiomyosarcoma histology for a lower distant RFR, compared to other histologies (p = 0.003). Patients under 62 years had an improved survival (p = 0.002) and local RFR (p = 0.02), and patients presenting with recurrent disease had improved survival (p = 0.03). Sex, tumor size, or grade, or the use of adjuvant chemotherapy were not predictive for any of the endpoints tested. Those who received adjuvant irradiation following gross surgical clearance experienced a prolonged median locoregional RFR over those who did not, and this approached statistical significance for those receiving radiation doses > 35 Gy. (103 months vs. 30 months, p = 0.06). Statistical significance was reached (p = 0.02) if only the infield RFR was considered. CONCLUSIONS This study demonstrates that failure to achieve local control is the primary cause of treatment failure for patients with RSTS, and that postoperative irradiation in doses > 35 Gy after complete surgery delayed, but did not prevent local recurrence. Improvements in outcome for patients with RSTS will require alternate treatment strategies, and preoperative irradiation with an aggressive surgical attempt at complete excision is currently under investigation.

Collaboration


Dive into the Brian O'Sullivan's collaboration.

Top Co-Authors

Avatar

John Waldron

Princess Margaret Cancer Centre

View shared research outputs
Top Co-Authors

Avatar

Shao Hui Huang

Princess Margaret Cancer Centre

View shared research outputs
Top Co-Authors

Avatar

Jolie Ringash

Princess Margaret Cancer Centre

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

A. Bayley

Princess Margaret Cancer Centre

View shared research outputs
Top Co-Authors

Avatar

Andrew Hope

Princess Margaret Cancer Centre

View shared research outputs
Top Co-Authors

Avatar

Wei Xu

University of Toronto

View shared research outputs
Top Co-Authors

Avatar

Bernard Cummings

Princess Margaret Cancer Centre

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

John Kim

Princess Margaret Cancer Centre

View shared research outputs
Researchain Logo
Decentralizing Knowledge