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Bissett R.J.,Northeastern Ontario Regional Cancer Center
Chronic diseases in Canada | Year: 2010

Radon is a radioactive gas that emanates from uranium-bearing soil and porous rock. Although radon is most highly concentrated in areas of high uranium concentration, the presence of trace amounts of uranium in most ground sources means that all humans are exposed to radon to some degree. Radon migrates out of soil and rock into the surrounding air, resulting in accumulation in poorly ventilated or closed areas. Such areas represent the primary environments in which humans are exposed to radioactivity from radon to experience detrimental health effects. There is no convincing evidence that any cancers other than lung cancer are associated with exposure to radon. There is, on the other hand, consistent evidence of a substantially elevated risk of lung cancer among Canadians exposed to radon in certain occupational settings, particularly uranium mining. While the combined evidence for a positive association between residential radon exposure and lung cancer is less compelling, the inherent methodological difficulties in mounting such studies may render it impossible for any single study to detect the relationship more conclusively. The best available evidence to date from pooled analyses indicates a positive, but weak association between residential radon and lung cancer risk. Residential radon is of critical importance because it is ubiquitous; a small excess risk that may exist in relation to radon exposures encountered in a residential setting translates into the potential for a far greater number of excess cancers in the general population than does exposure of a relatively small number of miners, even though the latter may be exposed to much higher levels of ionizing radiation. Fortunately, a number of techniques are available to homeowners to reduce radon concentrations in their homes.

Alexander A.,British Columbia Cancer Agency | Crook J.,Princess Margaret Hospital | Jones S.,British Columbia Cancer Agency | Malone S.,Ottawa Regional Cancer Center | And 4 more authors.
International Journal of Radiation Oncology Biology Physics | Year: 2010

Purpose: To ascertain whether biochemical response to neoadjuvant androgen-deprivation therapy (ADT) before radiotherapy (RT), rather than duration, is the critical determinant of benefit in the multimodal treatment of localized prostate cancer, by comparing outcomes of subjects from the Canadian multicenter 3- vs 8-month trial with a pre-RT, post-hormone PSA (PRPH-PSA) ≤0.1 ng/ml vs those >0.1 ng/ml. Methods and Materials: From 1995 to 2001, 378 men with localized prostate cancer were randomized to 3 or 8 months of neoadjuvant ADT before RT. On univariate analysis, survival indices were compared between those with a PRPH-PSA ≤0.1 ng/ml vs >0.1 ng/ml, for all patients and subgroups, including treatment arm, risk group, and gleason Score. Multivariate analysis identified independent predictors of outcome. Results: Biochemical disease-free survival (bDFS) was significantly higher for those with a PRPH-PSA ≤0.1 ng/ml compared with PRPH-PSA >0.1 ng/ml (55.3% vs 49.4%, p = 0.014). No difference in survival indices was observed between treatment arms. There was no difference in bDFS between patients in the 3- and 8-month arms with a PRPH-PSA ≤0.1 ng/ml nor those with PRPH-PSA >0.1 ng/ml. bDFS was significantly higher for high-risk patients with PRPH-PSA ≤0.1 ng/ml compared with PRPH-PSA >0.1 ng/ml (57.0% vs 29.4%, p = 0.017). Multivariate analysis identified PRPH-PSA (p = 0.041), Gleason score (p = 0.001), initial PSA (p = 0.025), and T-stage (p = 0.003), not ADT duration, as independent predictors of outcome. Conclusion: Biochemical response to neoadjuvant ADT before RT, not duration, appears to be the critical determinant of benefit in the setting of combined therapy. Individually tailored ADT duration based on PRPH-PSA would maximize therapeutic gain, while minimizing the duration of ADT and its related toxicities. © 2010 Elsevier Inc. All rights reserved.

Crump M.,University of Toronto | Herst J.,Northeastern Ontario Regional Cancer Center | Baldassarre F.,McMaster University | Sussman J.,Juravinski Cancer Center | And 3 more authors.
Blood | Year: 2015

Case 1. Anne is a 23-year-old nursing student who presents with bilateral cervical, left supraclavicular, and left axillary adenopathy. Computed tomography (CT) scan of the thorax reveals a 6-cm anterior mediastinal mass. Biopsy of the left supraclavicular lymph node reveals classical nodular sclerosis Hodgkin lymphoma. A complete blood count is normal and the erythrocyte sedimentation rate (ESR) is 25 mm/h. CT scan of the abdomen/pelvis show normal liver and spleen and no evidence of abdominal lymphadenopathy. You are asked to advise her on the role of radiation therapy in her treatment plan. Case 2. John is a 48-year-old teacher who presents with chest pain following a hockey game. A chest radiograph reveals mediastinal widening, and a contrast-enhancedCT scan shows a 7.5-cm anterior mediastinalmass, with enlarged paratracheal and right hilar lymph nodes. Image-guided core biopsy of the mediastinal mass is diagnostic for classical Hodgkin lymphoma. The hemoglobin is 130 g/L, white blood cell count and platelets are normal, and the ESR is 35 mm/h. John asks you about the role of radiotherapy in the management of his lymphoma. © 2015 by The American Society of Hematology.

Dayes I.,McMaster University | Rumble R.B.,Cancer Care Ontarios Program in Evidence Based Care | Bowen J.,Northeastern Ontario Regional Cancer Center | Dixon P.,Queens University | Warde P.,Radiation Treatment Program
Clinical Oncology | Year: 2012

Intensity-modulated radiotherapy (IMRT) is a newer method of radiotherapy that uses beams with multiple intensity levels for any single beam, allowing concave dose distributions and tighter margins than those possible using conventional radiotherapy. IMRT is ideal for treating complex treatment volumes and avoiding close proximity organs at risk that may be dose limiting and provides increased tumour control through an escalated dose and reduces normal tissue complications through organ at risk sparing. Given the potential advantages of IMRT and the availability of IMRT-enabled treatment planning systems and linear accelerators, IMRT has been introduced in a number of disease sites. This systematic review examined the evidence for IMRT in the treatment of breast cancer to quantify the potential benefits of this new technology and to make recommendations for radiation treatment programmes considering adopting this technique. Providing that avoidance of acute adverse effects associated with radiation is an outcome of interest, then IMRT is recommended over tangential radiotherapy after breast-conserving surgery, based on a review of six published reports including 2012 patients. There were insufficient data to recommend IMRT over standard tangential radiotherapy for reasons of oncological outcomes or late toxicity. Future research should focus on studies with longer follow-up and provide data on late toxicity and disease recurrence rates. © 2012 The Royal College of Radiologists.

Abara E.,Richmond Hill Urology Practice and Prostate Institute | Chivulescu I.,McMaster University | Clerk N.,York Central Hospital | Cano P.,Northeastern Ontario Regional Cancer Center | Goth A.,Sensenbrener Hospital
Journal of the Canadian Urological Association | Year: 2010

Localized renal cell carcinoma (RCC) responds well to surgery. Patients often question how long they have to be on surveillance after their surgery. Several follow-up patterns have been described in the literature. Until 2009, no published established Canadian guidelines existed to assist Canadian health-care practitioners in the surveillance of these patients. We present 3 cases of RCC that recurred 10 years or longer after the initial nephrectomy. These cases emphasize the need for careful long-term follow-up, as recommended in the Canadian Urological Association guidelines. We also discuss the optimism of prolonged disease survival in the era of novel therapeutic agents that target angiogenesis. © 2010 Canadian Urological Association.

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