Incidence and survival of inflammatory breast cancer between 1973 and 2015 in the SEER database

• Published in: Breast cancer research and treatment Vol. 185; no. 1; pp. 229 - 238
• Main Authors: Abraham, Hannah Grace, Xia, Yaoxuan, Mukherjee, Bhramar, Merajver, Sofia Diana
• Format: Journal Article
• Language: English
• Published: New York Springer US 2021; Springer; Springer Nature B.V
• Subjects: African Americans; Breast cancer; Breast Neoplasms - epidemiology; Cancer research; Edema; Epidemiology; Erythema; Female; Humans; Incidence; Inflammation; Inflammatory Breast Neoplasms - epidemiology; Inflammatory Breast Neoplasms - pathology; Medicine; Medicine & Public Health; Neoplasm Staging; Oncology; Patient outcomes; SEER Program; Survival; Survival Rate; Whites; Inflammatory breast cancer; Disparities; Survival; Incidence
• ISSN: 0167-6806; 1573-7217
• DOI: 10.1007/s10549-020-05938-2

Purpose
Inflammatory breast cancer (IBC) is an aggressive variant characterized by erythema, edema, and “peau d’orange” of the skin progressing within 6 months. We assessed the incidence and survival of IBC in the US over four decades.
Methods
Using SEER*Stat, a case list of IBC patients diagnosed between 1973 and 2015 (
n
 = 29,718) was extracted from SEER 18 registries by using a combination of morphology, stage, and extent of disease criteria. M1 and M0 patients were included. Age-adjusted incidence rates, relative survival rates, and mean survival time were calculated. Significance was determined as non-overlapping 95% confidence intervals.
Results
The overall incidence of IBC from 1973 to 2015 is 2.76 (2.73, 2.79) cases per 100,000 people, with white patients having an incidence rate of 2.63 (2.60, 2.67), black patients 4.52 (4.39, 4.65), and patients of other race 1.84 (1.76, 1.93). The overall IBC relative 5-year survival rate is 40.5% (39.0%, 42.0%), 42.5% (40.7%, 44.3%), and 29.9% (26.6%, 33.3%) for white patients and black patients, respectively. Patients diagnosed in 1978–1982 have a mean survival time of 62.3 (52.0, 72.6) months, while those diagnosed in 2008–2012 have mean survival time of 99.4 (96.4, 102.4) months. There is no significant difference in survival time between T4D patients and patients with other T staging and extent of disease coding consistent with clinical IBC presentation.
Conclusions
IBC survival has increased over four decades. Despite the improvement in survival for all racial groups, a persistent survival disparity that has not narrowed over two decades remains between white and black patients.