Epidemiology of inflammatory breast cancer (IBC)

Abstract

Inflammatory breast cancer (IBC) is a rare and aggressive form of breast cancer with unknown etiology and generally poor outcome. It is characterized by diffuse edema (peau d'orange) and redness (erythema), although either the disease itself or case definitions have varied over time and place, confounding temporal trends and geographic variations. In this review, we discuss case definitions for IBC and its clinical characteristics; describe its geographic variation, age and racial distribution, incidence and survival patterns, and summarize the very limited information on its epidemiologic risk factors. We also incorporate emerging data from the National Cancer Institute's (NCI) Surveillance, Epidemiology, and End Results (SEER) Program.

Fig. 1

Age-specific incidence rates for inflammatory breast cancer (IBC) in the Surveillance, Epidemiology, and End Results (SEER) program for 11 SEER tumor registries, i.e., Los Angeles, Utah, Atlanta (Metropolitan), New Mexico, Iowa, Hawaii, San Francisco-Oakland, Seattle (Puget-Sound), Detroit (Metropolitan), San Jose-Monterey, Connecticut.

Fig. 2

Age distribution (rates and frequency) for all breast cancer cases combined and IBC, stratified by ER expression. a) Panel A: Age-specific incidence rates. b) Panel B: Age density plots for all breast cancer cases combined. The density function represents smoothed estimates of the age frequency distribution at diagnosis, where the density multiplied by 100 equals the percentage. c) Panel C: Age density plots for IBC.

Fig. 3

Age distribution (rates and frequency) for all breast cancer cases combined and IBC, stratified by White, Black, and Asian or Pacific Islander (API) races. a) Panel A: Age-specific incidence rates. b) Panel B: Age density plots for all breast cancer cases combined. The density function represents smoothed estimates of the age frequency distribution at diagnosis, where the density multiplied by 100 equals the percentage. c) Panel C: Age density plots for IBC.

Fig. 4

Temporal trends for age-adjusted incidence rates among all breast cancer cases combined and inflammatory breast cancer (IBC) in the Surveillance, Epidemiology, and End Results (SEER) program. a) Panel A: Temporal trend for breast cancer cases diagnosed during the years 1973 to 2002. All breast cancer cases combined (n = 420,082) and IBC according to ICD-O 8530 (n = 2,935). b) Panel B: Temporal trend for breast cancer cases diagnosed during the years 1992 to 2002. All breast cancer cases combined (n = 256,995) and IBC according to the comprehensive SEER definition (n = 4,432; ICD-O 8530 or EOD-E 70 or EOD-S 998).

Fig. 5

Survival and hazard rate plots for all breast cancer cases combined and IBC, stratified by ER expression. a) Panel A: Survival function for all breast cancer cases combined. b) Panel B: Hazard plot for all breast cancer cases combined. c) Panel C: Survival function for all breast cancer cases combined. d) Panel D: Hazard function for all breast cancer cases combined.