Sarah Nicole Hamilton1, Scott Tyldesley2, Dongdong Li3, Robert Olson4, Mary McBride3. 1. Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Department of Radiation Oncology, British Columbia Cancer Agency-Vancouver Centre, Vancouver, British Columbia, Canada. 2. Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Department of Radiation Oncology, British Columbia Cancer Agency-Vancouver Centre, Vancouver, British Columbia, Canada. Electronic address: styldesl@bccancer.bc.ca. 3. Cancer Control Research Department, British Columbia Cancer Agency-Vancouver Centre, Vancouver, British Columbia, Canada. 4. Department of Radiation Oncology, British Columbia Cancer Agency-Centre for the North, Prince George, British Columbia, Canada.
Abstract
PURPOSE: This study was undertaken to determine whether there was an increased risk of second malignancies (SM), particularly lung cancer, in early stage breast cancer patients treated with the addition of nodal fields to breast and/or chest wall radiation therapy (RT). MATERIALS AND METHODS: Subjects were stage I/II female breast cancer patients 20 to 79 years of age, diagnosed between 1989 and 2005 and treated with adjuvant RT at our institution. Patients were included if they survived and did not have SM within 3 years of diagnosis. Standardized incidence ratios (SIR) with 95% confidence intervals (CI) were calculated to compare SM incidence to cancer incidence in the general sex- and age-matched populations. Secondary malignancy risks in patients treated with local RT (LRT) to the breast/chest wall were compared to those in patients treated with locoregional RT (LRRT) to the breast/chest wall and regional nodes, using multivariate regression analysis (MVA) to account for covariates. RESULTS: The cohort included 12,836 patients with a median follow-up of 8.4 years. LRRT was used in 18% of patients. The SIR comparing patients treated with LRT to the general population was 1.29 (CI: 1.21-1.38). No statistically significant increased incidence of in-field malignancies (SIR, 1.04; CI: 0.87-1.23) and lung cancers (SIR, 1.06; CI: 0.88-1.26) was detected. The SIR comparing patients treated with LRRT to the general population was 1.39 (CI: 1.17-1.64). No statistically significant increased incidence of in-field malignancies (SIR, 1.26; CI: 0.77-1.94) and lung cancers (SIR, 1.27; CI: 0.76-1.98) was detected. On MVA comparing LRRT to LRT, the adjusted hazard ratio was 1.20 for in-field malignancies (CI: 0.68-2.16) and 1.26 for lung cancer (CI: 0.67-2.36). The excess attributable risk (EAR) to regional RT was 3.1 per 10,000 person years (CI: -8.7 to 9.9). CONCLUSIONS: No statistically significant increased risk of second malignancy was detected after LRRT relative to that for LRT. The upper limit of the EAR was approximately 1% at 10 years.
PURPOSE: This study was undertaken to determine whether there was an increased risk of second malignancies (SM), particularly lung cancer, in early stage breast cancerpatients treated with the addition of nodal fields to breast and/or chest wall radiation therapy (RT). MATERIALS AND METHODS: Subjects were stage I/II female breast cancerpatients 20 to 79 years of age, diagnosed between 1989 and 2005 and treated with adjuvant RT at our institution. Patients were included if they survived and did not have SM within 3 years of diagnosis. Standardized incidence ratios (SIR) with 95% confidence intervals (CI) were calculated to compare SM incidence to cancer incidence in the general sex- and age-matched populations. Secondary malignancy risks in patients treated with local RT (LRT) to the breast/chest wall were compared to those in patients treated with locoregional RT (LRRT) to the breast/chest wall and regional nodes, using multivariate regression analysis (MVA) to account for covariates. RESULTS: The cohort included 12,836 patients with a median follow-up of 8.4 years. LRRT was used in 18% of patients. The SIR comparing patients treated with LRT to the general population was 1.29 (CI: 1.21-1.38). No statistically significant increased incidence of in-field malignancies (SIR, 1.04; CI: 0.87-1.23) and lung cancers (SIR, 1.06; CI: 0.88-1.26) was detected. The SIR comparing patients treated with LRRT to the general population was 1.39 (CI: 1.17-1.64). No statistically significant increased incidence of in-field malignancies (SIR, 1.26; CI: 0.77-1.94) and lung cancers (SIR, 1.27; CI: 0.76-1.98) was detected. On MVA comparing LRRT to LRT, the adjusted hazard ratio was 1.20 for in-field malignancies (CI: 0.68-2.16) and 1.26 for lung cancer (CI: 0.67-2.36). The excess attributable risk (EAR) to regional RT was 3.1 per 10,000 person years (CI: -8.7 to 9.9). CONCLUSIONS: No statistically significant increased risk of second malignancy was detected after LRRT relative to that for LRT. The upper limit of the EAR was approximately 1% at 10 years.
Authors: Hae Lin Cho; Vedang Murthy; Kent W Mouw; Anthony V D'Amico; Paul L Nguyen; Jonathan E Leeman; Edward Christopher Dee Journal: Prostate Date: 2022-06-02 Impact factor: 4.012