Radiotherapy for left-sided breast cancer during 1973-1982 significantly increased cardiac mortality compared to right-sided cancer, with the mortality ratio reaching 1.90 at 20 or more years.
Cohort (n=558,871)
Yes
Does radiotherapy for breast cancer increase long-term mortality from heart disease and lung cancer in women with invasive breast cancer?
Radiation-related mortality risks for heart disease and lung cancer following breast cancer radiotherapy are larger in the third decade after exposure than during the first two decades.
Effect estimate: Mortality Ratio 1.90 (95% CI 1.52-2.37)
p-value: p=<0.001
BACKGROUND: Radiation-related heart disease and lung cancer can occur following radiotherapy for breast cancer but the duration of any mortality risk is uncertain. METHODS: Mortality ratios, by laterality of breast cancer, were estimated using Poisson regression for 558 871 women recorded with breast cancer during 1973-2008 in the Surveillance, Epidemiology and End Results (SEER) cancer registries and followed until 01 January 2009. RESULTS: For women diagnosed with breast cancer during 1973-1982 and given radiotherapy shortly afterwards, the cardiac mortality ratios, left-sided vs right-sided, were 1.19 (1.03-1.38), 1.35 (1.05-1.73), 1.64 (1.26-2.14) and 1.90 (1.52-2.37) at <10, 10-14, 15-19 and 20+ years since diagnosis (2p for trend: <0.001). The lung cancer mortality ratios, ipsilateral vs contralateral, in these women were 1.05 (0.57-1.94), 2.04 (1.28-3.23) and 3.87 (2.19-6.82) at <10, 10-19 and 20+ years, respectively, (2p for trend: 0.002). For women irradiated during 1983-92 there was evidence of radiation-related mortality for lung cancer, but not for heart disease. For women irradiated since 1993 there is, as yet, little evidence of any radiation-related mortality. CONCLUSION: In this population, the radiation-related risks were larger in the third decade after exposure than during the first two decades.
Henson et al. (Thu,) conducted a cohort in Breast cancer (n=558,871). Radiotherapy for left-sided breast cancer vs. Radiotherapy for right-sided breast cancer was evaluated on Cardiac mortality at ≥20 years (left-sided vs right-sided) for women irradiated 1973-1982 (Mortality Ratio 1.90, 95% CI 1.52-2.37, p=<0.001). Radiotherapy for left-sided breast cancer during 1973-1982 significantly increased cardiac mortality compared to right-sided cancer, with the mortality ratio reaching 1.90 at 20 or more years.