Coding of specific subgroups of myelodysplastic syndromes in a population-based cancer registry: prospects for improvement.

Myelodysplastic syndromes (MDS), reportable to US cancer registries for diagnoses since 2001, are a group of myeloid neoplasms heterogeneous in prognosis and treatment, and of growing importance in an aging population. In US registries that have reported incident MDS cases by subgroup, about 50%-67% of cases have been coded as MDS "not otherwise specified" (NOS) in the International Classification of Diseases for Oncology Version 3 (ICD-O-3). For this study, MDS cases diagnosed in 2001-2009 and reported to the population-based Connecticut Tumor Registry (CTR) were analyzed. MDS was coded as NOS for 573 (56.7%) of 1,011 cases, but the proportion varied among reporting facilities hospitals (ie, from 0 to 100%), with several statistical outliers. In pathology reports obtained for 130 CTR patients diagnosed with MDS in 2008-2009, 84% of the 62 patients coded as NOS had information on a key element (ie, % of blasts in bone marrow) in ICD-O-3 coding and other classifications of MDS subgroups. These findings suggest that central cancer registries may want to work with hospital tumor registrars in improving reporting of specific MDS subgroups using ICD-O-3. The addition of % blasts from pathology reports to the site-specific factors for MDS in the Collaborative Staging System could be proposed.