Trends in inflammatory breast carcinoma incidence and survival: the surveillance, epidemiology, and end results program at the National Cancer Institute.
BACKGROUND
Inflammatory breast carcinoma (IBC) appears to be a clinicopathologic entity distinct from noninflammatory locally advanced breast cancer (LABC). We examined incidence and survival trends for IBC in Surveillance, Epidemiology, and End Results (SEER) Program data with a case definition designed to capture many of its unique clinical and pathologic characteristics.


METHODS
We analyzed breast cancer cases diagnosed in the SEER 9 Registries (n = 180,224), between 1988 and 2000. Breast cancer cases were categorized using SEER's "Extent of Disease" codes in combination with International Classification of Diseases for Oncology morphology code 8530/3 and classified as IBC (n = 3648), LABC (n = 3636), and non-T4 breast cancer (n = 172,940). We compared changes in incidence rates over 3-year intervals by breast cancer subtype and race using SEER*Stat. Survival differences by breast cancer subtype and race were assessed using Kaplan-Meier curves and log-rank statistics. All statistical tests were two-sided.


RESULTS
Between 1988 and 1990 and 1997 and 1999, IBC incidence rates (per 100,000 woman-years) increased from 2.0 to 2.5 (P < .001), whereas those for LABC declined (2.5 to 2.0, P = .0025), as did those for non-T4 breast cancer (108 to 101, P = .0084). IBC incidence rates were statistically significantly higher in black women (3.1) than in white women (2.2) during the study period (P < .001). Women diagnosed with IBC had statistically significantly poorer survival than women with either LABC or non-T4 breast cancer (log-rank test, P < .001). Median survival of women with IBC (2.9 years) was statistically significantly shorter than that of women with LABC (6.4 years; P < .0001) or non-T4 breast cancer (> 10 years, P < .0001). Black women with IBC or LABC had poorer survival than white women with IBC or LABC, respectively (log-rank test, P < .001).


CONCLUSIONS
Throughout the 1990s, IBC incidence rose, and survival improved modestly. Substantial racial differences were noted in age at diagnosis, age-specific incidence rates, and survival outcomes.
Department of Epidemiology and Biostatistics, The George Washington University School of Public Health and Health Services, Washington, DC, USA. hancek@mail.nih.gov
Kenneth W
KW
Hance
William F
WF
Anderson
Susan S
SS
Devesa
Heather A
HA
Young
Paul H
PH
Levine
D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data*; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D001943:Breast Neoplasms / Q000737:chemistry / Q000453:epidemiology* / Q000401:mortality / Q000473:pathology; D002277:Carcinoma / Q000737:chemistry / Q000453:epidemiology* / Q000401:mortality / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D015994:Incidence; D007249:Inflammation; D008875:Middle Aged; D011960:Receptors, Estrogen / Q000032:analysis; D012107:Research Design; D018426:SEER Program; D015996:Survival Rate / Q000639:trends; D014481:United States; D044465:White People / Q000706:statistics & numerical data*
D014408:Biomarkers, Tumor; D011960:Receptors, Estrogen