Survey Finds Three-fold Rise In Lung Cancer

Press, Volume C, Issue 29695, 13 December 1961, Page 16

Survey Finds Three-fold Rise In Lung Cancer

Lung cancer was being found three times more often in persons being X-rayed in the tuberculosis survey than when the survey began six years ago, the Deputy Medical Officer of Health (Dr. F. A. de Hamel) said yesterday. In 1956-57, one case of primary lung cancer was found, on average, in every 20,000 X-rays, said Dr. de Hamel. During 1958-59 the average was one in 10,000, and during 1960-61 it has been one in 6000. In the Christchurch city survey, seven definite cases of primary lung cancer had been discovered in the first 43,000 examined, and two more were under investigation. In addition, there were three cases of secondary lung cancer, where cancer elsewhere had produced shadows on the lung. The definite primary cases were all in men between 40 and 68 years.

“Considering that very many of those phon graphed were women, an i many others younger 'uen, the disease among the middleaged and elderly men must be much commoner J.an once in every 6000,” Dr. ce Hamel said. “Exactly how common we shall not be able to say until the figures have been processed by a statistician. “We cannot say, howezer, that the propo r t.on of lung cancer cases throughout this age-group is the same as among those we are getting along to the X-ray units,” he added. "It could be that we get a larger proportion of those with active disease than of the general population, because those who ere at a fairly advanced stale of the disease may well bj uncomfortable and make an effort to come for that reason. On the other hand, it could be that we tend to get a larger proportion of the younger age-groups than of those where lung cancer is generally found. What is certain is that a great dial more disease is being found among those who do come to the units. “The trend is following that m the United Kingdom, hut with a lag of several yea- s. The proportion of cases we are now finding is similar to that in a unit with which I

was working tn Britain in 1953-54. That unit is now discovering cases at the rate of one in every 1800. three times as frequently as it was then. Smoking Blamed "What seems to ba happening is that, in both countries, we are witnessing the effects of the large-scale increase in tobacco smoking, and particularly cigarette snoozing, during the last 29 to 30 years. We do not know how long it takes for continuous cigarette smoking to pro luce lung cancer, and the time certainly varies from one individual to another but 20 to 30 years seems a tenable figure. “There may, of course, be other factors, and this seems almost certain since a small minority of the lung cancer victims have never smoked at all. A number of rir pollutions are strongly suspected of giving rise to lung cancer, and benzpyrene, whicn is found in cigarettes and is believed to be one of the me in causative agents of cancer through smokir.g, is also found in some industrial , nd household smokes. Jdo not think there is a dangerous amount of benzpyrene in New Zealand smokes, -,ut he Dominion Laboratorv of t h e Department of Scientific <md Industrial Research is mvestigating this possibility.

“Persons working with cer ! i tain radioactive ores are also - i known to contract c?:.cer. but:l as far as I know this does i.ot apply to any ore mined in i New Zealand.’’ I Asked whether an increase t in the frequency of Christ- 1 church winter ‘smogs” might t be partly responsible for a s rise in the numbers of lung j cancer cases, Dr. d-: Hamel i < said that this was quite pos-it sible, but the numhe's found: were still too small "or a pro- 1 per comparison io be made ; between the figures for town t and country. The region t covered by the Ch-i-'cchurch ; mass X-ray service included ) the whole of the Sou’h Island 1 north of the Waitaki i]