Abstract
Background/Aims Rare cancers are challenging to study, both epidemiologically and clinically, as it is difficult to ascertain enough cases to achieve adequate statistical power or to be representative of a vast range of exposures. Further, as the complexity of unraveling the natural history of disease has increased, a large investigator team with diverse expertise is required to optimize the scientific contributions that can be mined from research projects. The HMOCRN provides a setting that can overcome these barriers. Although many studies evaluate all lymphomas combined, lymphoma consists of over 50 rare histological subtypes with varying incidence and survival rates and epidemiological features. Ideally, each histological subtype should be considered separately in etiological studies, but even the most common, diffuse large B cell lymphoma, has a SEER incidence of only 7.5 per 100,000 in men and 5.0 per 100,000 in women. Other lymphoma types range in incidence from <0.1 cases per 100,000 for NKT cell lymphoma to 2.8 per 100,000 for Hodgkin’s Disease in all race-sex groups combined, to the highest rate found for a population subgroup, only 8.8 per 100,000 for multiple myeloma in African American men.
Methods We have assembled a multi-disciplinary team interested in lymphoma and pharmacoepidemiology that includes investigators with clinical, epidemiological and biostatistical expertise from six HMORN sites, two US universities, the NCI, and an international investigator who first initiated the project.
Results Combining data from these HMOCRN sites from 1998–2008, we ascertained 1479 Hodgkin’s Disease cases, 3385 multiple myelomas, 771 T-cell lymphomas, (including 390 mycosis fungoides cases and 158 mature T-cell lymphomas), 3000 chronic lymphocytic leukemias, 1357 mature B cell lymphomas, 3883 diffuse large B cell lymphomas, 2188 follicular lymphomas, and 992 marginal zone B cell lymphomas.
Conclusions These numbers provide a unique opportunity to analyze many of the lymphoma subtypes as well as consider multiple confounders and effect modifiers, thus highlighting the strength of the HMOCRN setting for the study of uncommon diseases. Further, such multi-site studies allow for variation in study population geography and patient and treatment diversity, as well as embrace intellectual capital from numerous HMOCRN investigators and external collaborators.
