Rising incidence of lymphoid malignancies--true or false?

The report contrasts the ascertainment of cases by the regional cancer registry with a specially designed search for records and pathology material which was then submitted to critical review irrespective of the original diagnosis. Boundary changes over the intervening years were accounted for and the results contrasted between time periods and with the cancer registry records. A large proportion of cancer registry cases were never subjected to histopathological diagnosis and comparisons between the new data and records are not easy to undertake. The study describes a probable true rise in the incidence of follicular non-Hodgkin's lymphoma in certain parts of Yorkshire over the last 20 years; there is less evidence of a similar change in Hodgkin's disease incidence over the same period of time.