1. ¹Surveillance and Risk Assessment Division, Centre for Chronic Disease Prevention and Control, Population and Public Health Branch, Health Canada, Ottawa, ON, Canada K1A 0K9
2. ²Ottawa Regional Cancer Centre, Ottawa, ON, Canada K1H 8L6

Correspondence: Dr A-M Ugnat, Surveillance and Risk Assessment Division, Centre for Chronic Disease Prevention and Control, Population and Public Health Branch, Health Canada, 120 Colonnade Road, Address Locator 6702A, Ottawa, ON, Canada K1A 0K9; E-mail: Anne-Marie_Ugnat@hc-sc.gc.ca

Received 14 July 2003; Revised 9 December 2003; Accepted 17 December 2003; Published online 24 February 2004.

Abstract

This study examined the 5-year survival of 2192 breast cancer women diagnosed between 1994 and 1997 in Ottawa, Canada, by age, TNM stage, histology, grade and treatment, including assessment of the independent value of variables in defining prognosis. Our results showed that age, stage, treatment and grade significantly influenced outcome regardless of the confounding factors considered, with histology failing to achieve significant independent prognostic information. The survival rates were highest at ages 50–69 years for stage I and at ages 40–49 years for stages II–IV. The rates were lowest at ages 39 years for stages I–II and at ages 70 years for stages III–IV. The differences in survival between grade 1 and grade 3 were 9% in stage I and 20% in stage II. The treatment leading to the best survival was surgery plus radiation for stages I–II and surgery combined with chemotherapy for stages III–IV. Lobular carcinoma had a better prognosis than ductal carcinoma; this can be explained by more grade 1 and less grade 3 cases in lobular carcinoma. The worse prognosis for young patients than other ages can be explained by their higher proportion of poorly differentiated cancers. Stage I patients aged 50–69 years having the best survival is likely due to the earlier diagnosis achieved through screening.