Tertiary Center Referral Patterns for Myelodysplastic Syndrome (MDS) Patients Are Suggestive of Age and Race Disparities

Abstract 1881

Age- and race-based differences in disease characteristics, referral patterns, treatments and treatment outcomes, have been demonstrated in a number of malignancies. For MDS, data from Surveillance, Epidemiology and End Results (SEER) and North American Association of Central Cancer Registries (NAACCR) show no difference in age-adjusted incidence of MDS by race, and Veterans Administration data show no difference in overall survival by race. Otherwise, there is limited information on racial differences in clinical and biological characteristics in referral patterns and access to treatment. We performed a retrospective review of records on MDS patients evaluated at the University of Maryland Greenebaum Cancer Center (UMGCC) between 2000 and 2010 for race, age at diagnosis and at referral to UMGCC, time to referral in months, blast percentage at diagnosis and at referral, karyotype, etiology (de novo or therapy-related), and transformation to acute myeloid leukemia (AML) at the time of referral or subsequently. Diagnosis was based on blood and bone marrow findings consistent with any World Health Organization (WHO) subtype of MDS, including chronic myelomonocytic leukemia. Cytogenetic findings were classified into good-, intermediate-, and poor-risk categories based on the criteria used in the International Prognosis Scoring System (IPSS). A total of 162 patients were identified, of whom 125 (77%) were white and 27 (17%) were black. Black and white patients were 59% and 63% male, respectively (p NS). The median age at diagnosis for all MDS patients referred to UMGCC was 63 years. Of note, black patients were diagnosed at a significantly younger age than white patients (median age, 59 vs. 67 years; p=.003) and were also significantly younger at the time of referral (median age, 62 vs. 68.5 years; p=.001). There was also a trend toward a longer time interval from diagnosis to referral for blacks, compared to whites (median 9 vs. 3 months; p=.14). While both groups had a significant increase in the median blast percentage from the time of diagnosis to the time of referral, there was no difference between blacks and whites in median blast percentage at diagnosis (median 6% vs. 5%; p NS) or at time of referral (median 12% for both; p NS). The proportion of patients with therapy-related MDS was similar in blacks and white patients (18% vs. 19%; p NS). Additionally, there were no significant differences in cytogenetic findings, including good-, intermediate- and poor-risk categories, normal and complex karyotypes, isolated del(5q), chromosome 7 abnormalities and trisomy 8, between blacks and whites. Finally, there was no difference in incidence of transformation to AML at the time of referral (30% vs. 26%; p NS) or subsequently (37% vs. 50%; p NS). The median age at diagnosis for our patients was lower than that of the general MDS population based on SEER data (median age of 76 years at diagnosis), suggesting lower rates of tertiary center referral with increasing age. Moreover the fact that, among MDS patients seen at UMGCC, black patients were significantly younger than white patients indicates either a younger median age of black compared to white MDS patients in the general population, or additional disparities in referral patterns. The trend toward a longer time interval from diagnosis to referral of black patients provides partial support for the latter explanation, but further research on population-level disease incidence and referral and treatment patterns is warranted. Disparities in referral patterns could have an increasing potential to impact outcomes, in view of the recent availability of therapies that modify disease natural history and prolong survival, and the increasing availability of options for hematopoietic stem cell transplantation for older patients.