“Factors ” In Leukemia

Press, Volume CIII, Issue 30542, 10 September 1964, Page 1

“Factors ” In Leukemia

Leukemia may well be induced by a succession of “predisposing factors,” rather than having one specific cause, Dr. A. J. Hale, senior lecturer in pathology at St. Thomas’s Hospital Medical School, London, and consultant pathologist to the hospital, said in Christchurch yesterday.

Dr Hale is here to instruct and advise the staff of the Cytogenetics Unit of the Canterbury and West Coast division of the New Zealand Cancer Society on the operation of new equipment for leukemia research. Genetic tendencies fairly certainly played a part in producing leukemia in some patients, and radiation had

also been implicated in certain cases, Dr. Hale said. Viruses had been shown responsible for leukemia in fowls and mice, and it was possible the same could be true in humans. Certain drugs might also contribute. “The sort of thing we are considering is that a child with some inherited predisposition towards leukemia may be irradiated in its mother’s womb during a prenatal X-ray examination. Later the child—perhaps by now an adult—may be given relatively large doses of some predisposing drug during a serious illness. The defences are progressively weakened, and eventually a virus may succeed in establishing itself within one or more cells and a leukemia is under way,” Dr. Hale explained. “The chances of all these events occurring to any one individual are small and one event may in itself have no predisposing effect.”

The complicity of drugs was not proved, as cause and effect were not easy to separate. A person with leukemia had a much lower resistance than a normal person against other diseases, such as pneumonia or meningitis, and it could be that the onset of another disease could be merely a symptom of the deeper trouble. Much the same was true of viral infection and leukemia it was not certain whether the viruses found in leukemia cells were “drivers” or “passengers.” As to the possible harmful effects of drugs or medical irradiations, the slight risk involved had to be balanced against the likely good these would do. More Diagnosed Asked whether leukemia was on the increase. Dr. Hale said th?re was certinly a rise in the number of cases diagnosed, but this might not mean the disease was any

more common. Diagnosis was more certain than a few years ago; moreover, since treatments in many other diseases had improved, patients , often survived illnesses which would formerly probably have killed them and so lived long enough for the leukemia to be evident. Further, the extension of the average life expectancy of the population meant that some chronic leukemias which more commonly beset elderly persons, were now found more often because there were more people in the susceptible age-range. “Although no effective and final answer to leukemia is yet in sight, the management of the condition has improved markedly over the last few years and our knowledge of the basic chemical processes involved has been greatly extended. What is needed is more information and this can only be obtained through properly planned and directed research,” he said.