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Summary This is the first report of a case-control epidemiological study on lymphomas and leukaemias occurring in Yorkshire during 1979-84. This paper deals with the results of the Hodgkin's disease analysis comprising 248 cases and 489 controls. The results indicate support for previous work with respect to small family size and past history of infectious mononucleosis. Positive observations made in a previous pilot study are also confirmed and extended with respect to associations with certain chronic skin lesions, dental anaesthesia and familial factors. Negative associations are described with respect to X-ray exposures and cigarette smoking. It is proposed that these results fit into a general hypothesis that these conditions are the result of interaction between infectious agents and altered immunity in those persons genetically predisposed. the control group but the majority of controls were in hospital either due to an accident or for cold surgery. All interviews were conducted by trained interviewers, usually in hospital, using a standard questionnaire covering all aspects of past life relating to occupation, hobbies, personal habits, drug ingestion, family history and past medical history. Hospital and GP records were checked to confirm the accuracy of drug and medical histories. Cancer in other blood relatives was also cross-checked with the cancer registries or by death certificate perusal. All data were coded, computerised and validated by a trained group not involved with interviewing. The case-control statistics were produced using the programmes of Rothman and Boice (1979), using their stratified techniques.Two levels of analysis were undertaken: firstly, by pooling age groups, disease subtype and sex; and, secondly, by stratifying where possible by sex, age (15-35yr vs. 36+yr of age), and subtypes of disease. Results Cases studiedThe total number of HD cases occurring in the Region during the period exceeded that interviewed. The pilot study used the same data base but its results are independent of the analyses presented here. Non-significant or unassessable risk Some topics could not be studied adequately because the number of case or control responses was too small. Table I lists topics with 5 or less eligible cases and controls, which are not considered further. Table II shows non-significant differences at the 5% level of probability, having computed risk ratios less than 2.0. A few factors with higher risk ratios, which are not statistically significant in the pooled data, include the occupation of hand and machine sewers Br.

Summary This is the second report of a large case control study of lymphoma/leukaemia occurring in Yorkshire during , and deals with chronic lymphocytic leukaemia presenting either in its haematological (CLL) or more solid lymphomatous (malignant lymphoma-lymphocytic or MLL) forms. In all, 330 cases and 561 controls were interviewed. The results support the concept that CLL/MLL is a condition of multiple aetiologies with evidence for genetic predisposition through an excess of family cases, immune perturbation demonstrated by excessive previous skin diseases and phenylbutazone use, and viral involvement shown by links with infectious diseases and multiple sclerosis.The aetiology of chronic lymphocytic leukaemia (CLL) has All data were coded and validated by a separate trained been inadequately investigated in previous epidemiological group of staff and analysed using the statistics incorporated studies and has been confused further by its inclusion with in the programs of Rothman and Boice (1982), using other forms of leukaemia unrelated in terms of the purported stratified techniques and the age groups <70 years and > 70 cell of origin. In this study we

Five years' experience of operating a Regional Lymphoma Histopathology Panel is described. During this period, approximately 1400 cases were registered of which nearly 1200 were confirmed as malignant lymphoma. Complete concordance of diagnosis was achieved between submitting pathologists and the Panel in two-thirds of cases of Hodgkin's disease and just over half of non-Hodgkin's lymphoma. Most discrepancies in diagnosis were found to be of clinical importance in terms of prognosis and/or therapeutic management of patients. In approximately two-thirds of such instances disagreement arose because of wrong assignment of tumour grade within the main lymphoma class but in one-third of cases the main class of lymphoma was wrongly designated. Panel members experienced similar diagnostic problems as submitting pathologists although to a lesser extent. The existence of the panel has not reduced the proportion of cases causing diagnostic difficulty for submitting pathologists or panel members during the 5 year study period. The principal cause of death was ascertained from death certificates and autopsy findings in nearly half the cases dying during the study period. In approximately half of these infection (largely pulmonary) played a major role while most of the remainder died of various cardiovascular, pulmonary or renal disorders. There was no specific pattern relating to the main lymphoma class. It is concluded that whilst the panel fulfils a useful function in resolving diagnostic difficulties and standardizing lymphoma diagnosis its role is restricted somewhat by the limitations imposed by conventional morphological assessments.