Quality assurance in radiation therapy: clinical and physical aspects. Quality assurance: past and present in Canada.

Quality assurance in any clinical field must involve the three components of clinical care: (a) diagnosis and evaluation of patients; (b) medical decision making and treatment; and (c) outcome analysis. Nationally, there have been five annual reviews of outcome from all cancer centers following radiation therapy for cancer at various sites. These reviews are voluntary and organized through the Canadian Association of Radiologists. The objective is to determine if there are any major differences in outcome across the country, and if so, can such differences be related to the population treated or technique used. So far no major differences have been noted, although the reviews have led to improved communication between centers and constructive discussions of dose and technique. There is a National Tumour Reference Centre funded by the National Cancer Institute of Canada (NCIC) to provide assistance in establishing diagnostic criteria in pathology. Ontario has been active through the Ontario Cancer Treatment & Research Foundation and the Ontario Cancer Institute in establishing UICC TNM staging and reporting, together with an evaluative program for this staging system. All other quality assurance programs take place at the level of local centers.