- Email: [email protected]
Breast Cancer Incidence Rates in U.S. Women Are No Longer Declining
EPIDEMIOLOGY Breast Cancer Incidence Rates in U.S. Women Are No Longer Declining DeSantis C, Howlader N, Cronin KA, et al (American Cancer Society, Atlanta, GA; Natl Cancer Inst, Bethesda, MD) Cancer Epidemiol Biomarkers Prev 20:733-739, 2011
Background.dSeveral publications reported breast cancer incidence rates continued to decrease among white women, following the decline of about 7% from 2002 to 2003. However, none of these reports exclusively examined the trend after 2003. In this paper, we examined breast cancer incidence rates among non-Hispanic (NH) white women from 2003 to 2007 to determine whether the decrease in breast cancer incidence rates indeed persisted through 2007. In addition, we present breast cancer incidence trends for NH black and Hispanic women and postmenopausal hormone use for all three racial/ethnic groups. Methods.dBreast cancer incidence rates were calculated by race/ethnicity, age and ER status using data from the Surveillance, Epidemiology, and End Results (SEER) 12 registries for 2000 to 2007. Prevalence of postmenopausal hormone use was calculated using National Health Interview Survey data from 2000, 2005, and 2008. Results.dFrom 2003 to 2007, overall breast cancer incidence rates did not change significantly among NH white women in any age group. However, rates increased (2.7% per year) for ER+ breast cancers in ages 40 to 49, and decreased for ER breast cancers in ages 40 to 49 and 60 to 69. Similarly, overall breast cancer incidence rates did not change significantly for black and
Hispanic women. Hormone use continued to decrease from 2005 to 2008 in all groups, although the decreases were smaller compared to those from 2000 to 2005. Conclusions.dThe sharp decline in breast cancer incidence rates that occurred from 2002 to 2003 among NH white women did not continue through 2007. Impact.dFurther studies are needed to better understand the recent breast cancer trends. In this study, DeSantis and colleagues used SEER registry data to analyze recent trends in breast cancer incidence. They reported a significant decline of 7% in breast cancer incidence from 2002 to 2003, consistent with prior reports. Importantly, they extended these previous findings by demonstrating the subsequent overall stability of breast cancer incidence rates through 2007. Further, although not statistically associated with incidence patterns, a contemporaneous decline in postmenopausal hormone use in a similarly aged population was delineated by the authors on the basis of National Health Interview Survey data. Previous studies using both aggregate-level data1 and individual patient-level data2 have corroborated the finding of declines in breast cancer incidence and risk after the discontinuation of hormonal therapy. However, this analysis by DeSantis and colleagues yielded several unexpected results. Interestingly, in this study cohort, although declines in hormone use persisted through 2008, the concomitant declines in breast cancer incidence did not persist. This discordant finding may reflect the multifacto-
rial contribution of various influences on breast cancer incidence: not only hormone use but also mammographic screening patterns and shifts in other environmental or socioeconomic factors. Additionally, in this study cohort, ER-positive breast cancer incidence appeared to increase slightly after 2003, which was a counterintuitive finding. The authors posit that the discontinuation of postmenopausal hormone therapy may have delayed both the progression and detection of occult breast cancers but may have ultimately contributed to a late rise in incidence rates after the initial decline. This contribution is theoretically possible but will require further validation using both clinical and population-based studies as well as pathophysiologic studies to confirm a plausible biological mechanism. Another important factor that should be considered is the investigators’ use of an imputation method to presume ER status in the 7% to 18% of patients whose receptor status was not known. This algorithm has not yet been validated and therefore may be an important source of misclassification error in the analysis. Further research using patient-level data with detailed knowledge of receptor status and hormone use and careful follow-up in the contemporary era is required. Evidence suggests that the nominal breast cancer incidence rate has experienced shifts over time simply because of mammographic screening patterns. A peak in incidence in the 1990s was correlated with a sharp rise in mammography use during that decade; likewise, the incidence rate stabilized after mammographic utilization rates stabilized in the early
Breast Diseases: A Year BookÒ Quarterly Vol 23 No 2 2012
137
2000s. Most recently, substantial controversy over mammographic screening guidelines, particularly for women age 40-50 years, has ignited debate in both the lay and scientific communities. In 2009, the US Preventive Services Task Force recommended against screening mammography before age 50.3 It is unclear how the ensuing debate and changes in guidelines will affect mammographic screening on a population level, and how, if at all, they will subsequently affect overall breast cancer incidence and age-specific and stage-specific breast cancer incidence rates over time. Finally, it is critical to note that incidence data in all of these prior studies were age standardized. Thus,
regardless of a decline or stabilization in relative incidence rates, the cumulative and absolute incidence rates of breast cancer are still expected to increase substantially over the next decade, simply because of the demographic shift reflected in the aging US population.4 The expected absolute, as well as relative, burden of this disease must still be considered in resource allocation and public health policy decisions.
Poorer Survival Outcomes for Male Breast Cancer Compared with Female Breast Cancer May Be Attributable to In-Stage Migration
ratios (aHR) and 95% confidence intervals (CI) using Cox regression models to compare breast cancer-specific and all-cause mortality by stage between males and females, controlling for potential confounding variables. Results.dThere were 246,059 patients with a first, single, primary breast cancer [1,541 (0.6%) male; 244,518 (99.4%) female]. Compared with females, males were more likely to be older, Black, married, diagnosed at more advanced stages, and treated with mastectomy (each P < 0.001). Males also were more likely to have lower grade and estrogen/progesterone receptorpositive tumors (each P < 0.001). After controlling for confounders, males were more likely to die from their breast cancer when compared with females, only if diagnosed with stage I disease (aHR 1.72, CI 1.15e2.61). For all-cause mortality, males were more likely than females to die at each stage of disease except stage IV.
Gnerlich JL, Deshpande AD, Jeffe DB, et al (Washington Univ School of Medicine, St Louis, MO; Saint Louis Univ School of Public Health, MO) Ann Surg Oncol 18:1837-1844, 2011
Background.dMale breast cancer accounts for less than 1% of all breast cancers, yet males have a worse prognosis than females with breast cancer. Methods.dUsing the 1988e2003 Surveillance, Epidemiology, and End Results Program data, we conducted a retrospective, population-based cohort study to investigate stage-specific differences in breast cancer-specific and allcause mortality between males and females. We calculated adjusted hazard
138
G. L. Smith, MD, PhD, MPH
References 1. Glass AG, Lacey JV Jr, Carreon JD, Hoover RN. Breast cancer incidence, 1980-2006: combined roles of
Breast Diseases: A Year BookÒ Quarterly Vol 23 No 2 2012
menopausal hormone therapy, screening mammography, and estrogen receptor status. J Natl Cancer Inst. 2007;99:1152-1161. 2. Chlebowski RT, Kuller LH, Prentice RL, et al. Breast cancer after use of estrogen plus progestin in postmenopausal women. N Engl J Med. 2009;360:573-587. 3. US Preventive Services Task Force. Screening for breast cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2009;151:716-726. 4. Smith BD, Smith GL, Hurria A, Hortobagyi GN, Buchholz TA. Future of cancer incidence in the United States: burdens upon an aging, changing nation. J Clin Oncol. 2009; 27:2758-2765.
Conclusions.dAlthough all-cause mortality was higher for men than women at all stages of nonmetastatic breast cancer, higher male breast cancer-specific mortality was attributed to poorer survival in stage I disease. However, this statistical difference is unlikely to be clinically relevant and attributable to in-stage migration. Male breast cancer (MBC) is an uncommon entity and, as such, precludes prospective study. However, over time, many relatively small retrospective series have documented several characteristics of MBC: (1) MBC patients more often have estrogen receptor-positive (ER+) and human epidermal growth factor receptor 2negative (HER2-) disease than their female counterparts1-3; (2) most MBC patients present at later disease stages, and many series have revealed that, on average, men are older at diagnosis than are women2; (3) most institutions
Background.dSeveral publications reported breast cancer incidence rates continued to decrease among white women, following the decline of about 7% from 2002 to 2003. However, none of these reports exclusively examined the trend after 2003. In this paper, we examined breast cancer incidence rates among non-Hispanic (NH) white women from 2003 to 2007 to determine whether the decrease in breast cancer incidence rates indeed persisted through 2007. In addition, we present breast cancer incidence trends for NH black and Hispanic women and postmenopausal hormone use for all three racial/ethnic groups. Methods.dBreast cancer incidence rates were calculated by race/ethnicity, age and ER status using data from the Surveillance, Epidemiology, and End Results (SEER) 12 registries for 2000 to 2007. Prevalence of postmenopausal hormone use was calculated using National Health Interview Survey data from 2000, 2005, and 2008. Results.dFrom 2003 to 2007, overall breast cancer incidence rates did not change significantly among NH white women in any age group. However, rates increased (2.7% per year) for ER+ breast cancers in ages 40 to 49, and decreased for ER breast cancers in ages 40 to 49 and 60 to 69. Similarly, overall breast cancer incidence rates did not change significantly for black and
Hispanic women. Hormone use continued to decrease from 2005 to 2008 in all groups, although the decreases were smaller compared to those from 2000 to 2005. Conclusions.dThe sharp decline in breast cancer incidence rates that occurred from 2002 to 2003 among NH white women did not continue through 2007. Impact.dFurther studies are needed to better understand the recent breast cancer trends. In this study, DeSantis and colleagues used SEER registry data to analyze recent trends in breast cancer incidence. They reported a significant decline of 7% in breast cancer incidence from 2002 to 2003, consistent with prior reports. Importantly, they extended these previous findings by demonstrating the subsequent overall stability of breast cancer incidence rates through 2007. Further, although not statistically associated with incidence patterns, a contemporaneous decline in postmenopausal hormone use in a similarly aged population was delineated by the authors on the basis of National Health Interview Survey data. Previous studies using both aggregate-level data1 and individual patient-level data2 have corroborated the finding of declines in breast cancer incidence and risk after the discontinuation of hormonal therapy. However, this analysis by DeSantis and colleagues yielded several unexpected results. Interestingly, in this study cohort, although declines in hormone use persisted through 2008, the concomitant declines in breast cancer incidence did not persist. This discordant finding may reflect the multifacto-
rial contribution of various influences on breast cancer incidence: not only hormone use but also mammographic screening patterns and shifts in other environmental or socioeconomic factors. Additionally, in this study cohort, ER-positive breast cancer incidence appeared to increase slightly after 2003, which was a counterintuitive finding. The authors posit that the discontinuation of postmenopausal hormone therapy may have delayed both the progression and detection of occult breast cancers but may have ultimately contributed to a late rise in incidence rates after the initial decline. This contribution is theoretically possible but will require further validation using both clinical and population-based studies as well as pathophysiologic studies to confirm a plausible biological mechanism. Another important factor that should be considered is the investigators’ use of an imputation method to presume ER status in the 7% to 18% of patients whose receptor status was not known. This algorithm has not yet been validated and therefore may be an important source of misclassification error in the analysis. Further research using patient-level data with detailed knowledge of receptor status and hormone use and careful follow-up in the contemporary era is required. Evidence suggests that the nominal breast cancer incidence rate has experienced shifts over time simply because of mammographic screening patterns. A peak in incidence in the 1990s was correlated with a sharp rise in mammography use during that decade; likewise, the incidence rate stabilized after mammographic utilization rates stabilized in the early
Breast Diseases: A Year BookÒ Quarterly Vol 23 No 2 2012
137
2000s. Most recently, substantial controversy over mammographic screening guidelines, particularly for women age 40-50 years, has ignited debate in both the lay and scientific communities. In 2009, the US Preventive Services Task Force recommended against screening mammography before age 50.3 It is unclear how the ensuing debate and changes in guidelines will affect mammographic screening on a population level, and how, if at all, they will subsequently affect overall breast cancer incidence and age-specific and stage-specific breast cancer incidence rates over time. Finally, it is critical to note that incidence data in all of these prior studies were age standardized. Thus,
regardless of a decline or stabilization in relative incidence rates, the cumulative and absolute incidence rates of breast cancer are still expected to increase substantially over the next decade, simply because of the demographic shift reflected in the aging US population.4 The expected absolute, as well as relative, burden of this disease must still be considered in resource allocation and public health policy decisions.
Poorer Survival Outcomes for Male Breast Cancer Compared with Female Breast Cancer May Be Attributable to In-Stage Migration
ratios (aHR) and 95% confidence intervals (CI) using Cox regression models to compare breast cancer-specific and all-cause mortality by stage between males and females, controlling for potential confounding variables. Results.dThere were 246,059 patients with a first, single, primary breast cancer [1,541 (0.6%) male; 244,518 (99.4%) female]. Compared with females, males were more likely to be older, Black, married, diagnosed at more advanced stages, and treated with mastectomy (each P < 0.001). Males also were more likely to have lower grade and estrogen/progesterone receptorpositive tumors (each P < 0.001). After controlling for confounders, males were more likely to die from their breast cancer when compared with females, only if diagnosed with stage I disease (aHR 1.72, CI 1.15e2.61). For all-cause mortality, males were more likely than females to die at each stage of disease except stage IV.
Gnerlich JL, Deshpande AD, Jeffe DB, et al (Washington Univ School of Medicine, St Louis, MO; Saint Louis Univ School of Public Health, MO) Ann Surg Oncol 18:1837-1844, 2011
Background.dMale breast cancer accounts for less than 1% of all breast cancers, yet males have a worse prognosis than females with breast cancer. Methods.dUsing the 1988e2003 Surveillance, Epidemiology, and End Results Program data, we conducted a retrospective, population-based cohort study to investigate stage-specific differences in breast cancer-specific and allcause mortality between males and females. We calculated adjusted hazard
138
G. L. Smith, MD, PhD, MPH
References 1. Glass AG, Lacey JV Jr, Carreon JD, Hoover RN. Breast cancer incidence, 1980-2006: combined roles of
Breast Diseases: A Year BookÒ Quarterly Vol 23 No 2 2012
menopausal hormone therapy, screening mammography, and estrogen receptor status. J Natl Cancer Inst. 2007;99:1152-1161. 2. Chlebowski RT, Kuller LH, Prentice RL, et al. Breast cancer after use of estrogen plus progestin in postmenopausal women. N Engl J Med. 2009;360:573-587. 3. US Preventive Services Task Force. Screening for breast cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2009;151:716-726. 4. Smith BD, Smith GL, Hurria A, Hortobagyi GN, Buchholz TA. Future of cancer incidence in the United States: burdens upon an aging, changing nation. J Clin Oncol. 2009; 27:2758-2765.
Conclusions.dAlthough all-cause mortality was higher for men than women at all stages of nonmetastatic breast cancer, higher male breast cancer-specific mortality was attributed to poorer survival in stage I disease. However, this statistical difference is unlikely to be clinically relevant and attributable to in-stage migration. Male breast cancer (MBC) is an uncommon entity and, as such, precludes prospective study. However, over time, many relatively small retrospective series have documented several characteristics of MBC: (1) MBC patients more often have estrogen receptor-positive (ER+) and human epidermal growth factor receptor 2negative (HER2-) disease than their female counterparts1-3; (2) most MBC patients present at later disease stages, and many series have revealed that, on average, men are older at diagnosis than are women2; (3) most institutions