title: What can we learn from the age- and race/ethnicity- specific rates of inflammatory breast carcinoma?
abstract: Inflammatory Breast Carcinoma (IBC), the most aggressive type of breast tumor with unique clinicopathological presentation, is hypothesized to have distinct etiology with a socioeconomic status (SES) component. Using the Surveillance, Epidemiology and End Results (SEER) Program data for 2004-2007, we compare incidence rates of IBC to non-inflammatory locally advanced breast cancer (LABC) among racial/ethnic groups with different SES. The analysis includes women 20-84 years of age. To examine evidence for the distinct etiology of IBC, we analyzed age-distribution patterns of IBC and non-inflammatory LABC, using a mathematical carcinogenesis model. Based on the Collaborative Staging Extension codes, 2,942 incident IBC cases (codes 71 and 73) and 5,721 non-inflammatory LABC cases (codes 40-62) were identified during the four-year study period. Age-adjusted rates of IBC among non-Hispanic White and Hispanic women were similar (2.5/100,000 in both groups). Similar rates were also found in non-inflammatory LABC in these two groups (4.8/100,000 and 4.2/100,000, respectively). In African-American women, the IBC (3.91/100,000) and non-inflammatory LABC (8.47/100,000) rates were greater compared with other ethnic/racial sub-groups. However, the ratio of rates of IBC/non-inflammatory LABC was similar among all the racial/ethnic groups, suggesting that African-American women are susceptible to aggressive breast tumors in general but not specifically to IBC. The mathematical model successfully predicted the observed age-specific rates of both examined breast tumors and revealed distinct patterns. IBC rates increased until age 65 and then slightly decreased, whereas non-inflammatory LABC rates steadily increased throughout the entire age interval. The number of critical transition carcinogenesis stages (m-stages) predicted by the model were 6.3 and 8.5 for IBC and non-inflammatory LABC, respectively, supporting different etiologies of these breast tumors.
authors.affiliation: Duke Cancer Institute, DUMC Box 2715, Durham, NC 27710, USA. dora.ilyasova@duke.edu
authors.forename: Dora
authors.initials: D
authors.lastname: Il'yasova
authors.forename: Sharareh
authors.initials: S
authors.lastname: Siamakpour-Reihani
authors.forename: Igor
authors.initials: I
authors.lastname: Akushevich
authors.forename: Lucy
authors.initials: L
authors.lastname: Akushevich
authors.forename: Neil
authors.initials: N
authors.lastname: Spector
authors.forename: Joellen
authors.initials: J
authors.lastname: Schildkraut
mesh_terms: D000328:Adult; D001741:Black or African American; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D015994:Incidence; D058922:Inflammatory Breast Neoplasms / Q000208:ethnology* / Q000473:pathology; D008875:Middle Aged; D008954:Models, Biological; D014481:United States / Q000453:epidemiology; D044465:White People; D055815:Young Adult