Racial and ethnic differences in risk of second primary cancers among breast cancer survivors.

Abstract

Purpose-Disparities exist in breast cancer (BC) outcomes between racial/ethnic groups in the United States. Reasons for these disparities are multifactorial including differences in genetics, stage at presentation, access to care and socioeconomic factors. Less is documented on racial/ ethnic differences in subsequent risk of second primary cancers (SPC). The purpose of this study is to evaluate the risk of SPC among different racial/ethnic groups of women with BC. Methods-Retrospective cohort of 134,868 Non-Hispanic White (NHW), 17,484 Black, 18,034 Hispanic and 19,802 Asian/Pacific Islander (API) women with stages I-III BC in twelve Surveillance, Epidemiology and End Results Program registries between 2001-2010. Standardized incidence ratios (SIR), 95% confidence intervals (CI) and absolute excess risks were calculated by comparing incidence of SPC in the cohort to incidence in the general population for specific cancer sites by race/ethnicity and stratified by index BC characteristics. Results-All women were at increased risks of second primary BC and acute myeloid leukemia (AML), with higher risk among more advanced stage index BC. Black and API women had higher SIRs for AML [4.86 (95% CI 3.05-7.36) and 5.00 (95% CI 3.26-7.32) respectively] which remained elevated among early-stage (I) BC cases. Conclusions-Women with a history of invasive BC have increased risk of SPC, most notable for second primary BC and AML. These risks for secondary cancers differ by race/ethnicity. Studies evaluating possible genetic and biobehavioral mechanisms underlying these differences

Incidence of second primary malignancy after breast cancer and related risk factors—Is breast‐conserving surgery safe? A nested case–control study

“…In terms of the risks of SPM at specific sites, our findings were comparable with previous observations for SPMs in the digestive system, respiratory system, genital system, endocrine system, hematopoietic system and contralateral breast . Based on our analysis of the site‐specific adjusted SIRs, we found an inverse association of age with SPM risk, which was in agreement with several studies but only inconsistent with a retrospective study from Italy .…”

Magnitude of reduction in risk of second contralateral breast cancer with bilateral mastectomy in patients with breast cancer: Data from California, 1998 through 2015

“…This method estimates the hazard rate ratio (HR) and 95% CI by modeling the hazard of the cumulative incidence function while controlling for the competing risk of death and adjusting for the variables shown in Table as potential confounders. Fine and Gray regression was used to estimate associations with the risk of breast cancer death, controlling for the competing risk of death from other causes, among patients undergoing BCT compared with those receiving other treatments, and Cox regression was used to estimate associations with risk of death from all causes.…”