Non-biased and complete case registration of lymphoid leukemia and lymphoma for five years: a first representative index of Japan from an epidemiologically stable Miyagi Prefecture

Abstract

Previous worldwide epidemiological studies on lymphoid leukemia and/or lymphoma (LL/L) had considerable bias because of difficulty in covering all clinical departments of hospitals in a restricted area (population base). These studies may not have reflected the actual number of newly diagnosed cases (incidence) strictly, or the true LL/L subtype frequencies. We searched all cases of newly diagnosed LL/L in Miyagi Prefecture over a 5-year period, including those that were discovered as LL/L sorely after autopsy. We registered the actual number of 2098 cases in the prefecture and calculated an accurate incidence rate (17.8 per 100,000 persons). Additionally, we identified more realistic and detailed frequencies of LL/L subtypes including the leukemic phase of some lymphomas. As Miyagi Prefecture is an area in which the population dynamics are relatively stable and representative of Japan, the result of our epidemiological study can be used as the first representative index of LL/L for Japan.

Keywords:

• Incidence rate
• lymphoma
• lymphoid leukemia
• registration

Acknowledgements

We thank the medical doctors, technologists and office workers of all hospitals and medical facilities in Miyagi Prefecture for cooperating with this work and for helpful discussions. This work was supported in part by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS KAKENHI No. Public Interest Incorporated Foundation 24590677/15K08609) and by the Public Interest Incorporated Foundation of Ichinohasama Memorial READ Blood Academy (Sendai, Japan, No. 2015-002).

Potential conflict of interest

Disclosure forms provided by the authors are available with the full text of this article at http://dx.doi.org/10.1080/10428194.2016.1183254.