Purpose: That patients can be ultimately cured of breast cancer has been questioned, because late deaths from the disease have been observed even several decades after the diagnosis. The purpose of this study was to investigate late mortality caused by breast cancer.
Patients and methods: Using the files of local hospitals and the Finnish Cancer Registry, we identified all patients with histologically diagnosed invasive breast cancer in a defined urban area (city of Turku, Finland) from 1945 to 1969 (n = 601). In 563 cases (94%), clinical data and histologic and autopsy slides could be reviewed, and these women had been monitored for a median of 29 years (range, 22 to 44; n = 66) or until death (n = 497).
Results: Mortality from breast cancer was observed even during the fourth follow-up decade, but if women who were diagnosed with contralateral breast cancer were excluded (n = 30), no deaths from breast cancer were identified after the 27th year of follow-up evaluation. The 30-year survival rates were 62% (95% confidence interval [CI], 54% to 70%), 19% (95% CI, 13% to 25%), and 0% for women with pN0 (node-negative) and pN1 or pN2 (node-positive) disease, respectively. High 30-year survival rates were found in small (pT1N0M0) unilateral cancers (80% alive; 95% CI, 66 to 94%), and in the lobular (45% alive; 95% CI, 31% to 59%) and the special histologic types (81% alive; 95% CI, 67% to 95%). These survival rates were obtained when correcting either for known intercurrent deaths or for mortality in the age- and sex-matched general population.
Conclusion: Breast cancer, node-negative and node-positive, may be permanently cured even if treated with locoregional therapy only. The survival figures listed here may be considered as minimum values, because women with breast cancer diagnosed in the same area from 1970 to 1984 showed significantly improved short-term (< 20 years) survival rates over those diagnosed from 1945 to 1969.