Hematologic neoplasms incidence categorised by WHO classification and centralization of treatment facilities in Japan: Analysing a nationwide Hospital-Based Cancer Registry data.

Abstract

e19348 Background: More than 55,000 patients are diagnosed as hematologic neoplasms in Japan. In this study incidence of hematologic neoplasms was categorised based on the World Health Organisation (WHO) classification, and centralisation of treatment facilities was analysed, using the nationwide Hospital-Based Cancer Registries (HBCR) which covers more than 65% of new cancer patients. Methods: The HBCR data for patients diagnosed in 2017 was used. We categorized patients in line with the 2017 Revision of WHO classification of lymphoid, myeloid neoplasms, and acute leukaemia. Incidence and age distribution was analysed by subtype. Centralisation of treatment facilities for haematological malignancy patients was also analysed. Hospitals were classified into four approximately equal groups based on patient volume per year (very high: over 108 patients; high: 43-107; low: 10-42; and very low: under 10). Results: In total, 51,936 patients in 809 hospitals were identified. Overall average age was 68.4 years (SD 16.5). 43.6% were diagnosed as mature B-cell neoplasms except plasma cell neoplasms, followed by 12.6% of myelodysplastic/myeloproliferative neoplasms and myelodysplastic syndromes, 10.1% of plasma cell neoplasms, 9.4% of myeloproliferative neoplasms, and 8.8% of acute myeloid leukaemia and related precursor neoplasms. 1,438 patients (2.8%) were diagnosed as precursor lymphoid neoplasms and 54.7% of these patients were under 10 years old. Looking at the age distribution of mature B-cell neoplasms, 70s were accounted for 32.6% and 60s were accounted for 26.4%. Among hematologic patients aged 70s, 46.4% were mature B-cell neoplasms and remaining 14.3% of myelodysplastic/myeloproliferative neoplasms. Most of patients received treatment at very high (62.1%, 206 hospitals) or high patient volume hospitals (28.5%, 200 hospitals). Only 1.8% of patients received treatment at very low patient volume hospitals (221 hospitals) which have less than 10 hematologic patients per year. Most of patients received treatment at very low patient volume hospitals were mature B-cell neoplasms. Conclusions: In this study, the first detailed analysis of the number of hematologic neoplasms by subtype was performed. Treatment facilities for hematologic neoplasms patients was almost centralised.