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ENVIRONMENT * ENVIRONNEMENT
Ms and ozone depleti*on: Be careful not to turn patients into "cancerphobes"
Peter P. Morgan, MD, DPH
E arly in February Jean Charest, the federal environment minister, reacted strongly to reports from US researchers that the ozone layer over the northern hemisphere could be reduced by as much as 40% in late winter and early spring. He urged Canadians to avoid exposure to sunlight as much as possible and told parents not to let their children play in the sun. Although he modified this position somewhat a few days later, Charest made Canadians conscious, in the bluntest possible way, that ozone depletion could become a national health threat. In March, an Angus Reid poll indicated that the message was getting across - about two-thirds of respondents said they would take extra precautions against exposure to the sun this year by wearing extra clothing and using sunscreens. The ozone "hole" that is causing the concern (see sidebar) is predicted to fill over as Canadians enter their sunny season, but concern is still great enough that Peter Morgan is a CMAJ consulting editor. APRIL 15, 1992
Environment Canada will release since people who work outdoors weekly ozone bulletins. These do not have higher rates of melread like stock market reports, anoma than those who work intelling us whether the market has side. gone up or down but not how Canadian physicians, always many investors have been en- strong believers in preventive riched or ruined. medicine, are strong on the idea The major ozone-related fear that UV overexposure is a preis that ultraviolet (UV) light trig- ventable pathogen or copathogen. gers malignant melanoma, a can- Dr. Donald Rosenthal, an Ottawa cer that is both preventable and dermatologist, says his concern treatable, yet sometimes metasta- about melanoma begins with his sizes so early that the game is lost. sketch of a person with a high-risk In the US, "the incidence of mela- profile: a blond, blue-eyed person noma has almost tripled in the who burns easily, has many dyslast four decades, and is growing plastic moles and a positive famifaster than that of any other can- ly history. Repeated quick suncer."' burns further increase the risk, Most Nordic countries report while a slow tan can be protective. a steady annual rise of about 5% Immunosuppressed patients, he in melanoma incidence in the past adds, may be running an even 40 years (World Health Organiza- greater risk - there is the possition, Press Release, Feb. 11, bility that UV light itself may 1992). In Canada, melanoma has affect the immune system adincreased at almost the same pace, versely. with 3000 cases and about 540 Dr. Lawrence Hurst, a plastic deaths now being reported yearly. surgeon in London, Ont., finds Although case reporting is far that he is operating on a growing from complete, at least 45 000 number of patients with melanononmalignant skin cancers occur mas and basal-cell and squamouseach year as well. However, as cell carcinomas; 95% of his referKoh' notes, the case against UV rals are from dermatologists, who radiation is not ironclad. The epi- in turn are confirming dysplastic demiologic and experimental evi- moles or melanomas on patients dence is somewhat conflicted, referred to them by family practiCAN MED ASSOC J 1992; 146 (8)
1397
tioners. His advice: "You can prevent 50% of lifetime UV exposure by adequate protection against excessive exposure to sunlight before age 18." Although pediatricians rarely see a case of melanoma, they are strongly prevention oriented. "I'm taking a much more aggressive policy in advising patients," observes Dr. Stanley Kardash of Ottawa. He recommends an industrial-strength sun blocker (with a blocking factor of 29 to 35), and that light clothing be worn on the beach.
Dr. William James agrees. "I bring it up a lot with parents," says James, a pediatrician at the Children's Hospital of Eastern Ontario in Ottawa. He says children should receive especially strong protection between 11 am and 2 pm, and suggests that a high-density blocker be put on 30 minutes before a child goes outside to play. Although the ozone issue received saturation media coverage during the winter, as the days lengthened there seemed to be little or no patient panic about I:- :-.:-.:....:..: .:..:..:...,.C:..:......:.. .;. ...
:!..'........::.:....-..-...: .;:....;... .:..".:....;:..:...
UV exposure. The American Academy of Dermatology, which has screened more than 358 000 people for skin cancer in recent years, says it has received few calls from citizens, but many from reporters, in response to ozonehole stories. Rosenthal is facing a growing number of questions about melanoma, but says he is still much more likely to bring up the subject of protection against the sun than his patients. Sunburn may prove to be the only stimulus that will heighten patients' 1. :. :
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1398
CAN MED ASSOC J 1992; 146 (8)
:.
LE 1 5 AVRIL 1992
Widely advertised UV filtering sunglasses may perform as advertised, blocking all the UV radiation in its target range, but still may not cover the entire UV range. And labels can be misleading; unscrupulous vendors can buy impressive labels to affix to low-quality glasses. Dr. Dario Lorenzetti of Montreal, current president of the Canadian Ophthalmological Society, adds that ocular melanoma has not been shown to be related to UV exposure. There seems to be little we can do about the capricious thinning of the ozone layer, at least at present. Down here on earth, prevention is the key word. The "Montreal Protocol" that was
health concern, he added. UV radiation can also damage another epidermal organ, the eye. It has been implicated in the formation of conjunctival pinguecula and pterygia, nuclear cataracts, age-related macular degeneration of the retina, and as a cause of a corneal disorder that revels in the name of Labrador keratopathy. Prevention is a bit tricky, says Dr. Brent Maclnnis, an Ottawa ophthalmologist. Almost all biologic damage is caused by radiation in the UV-B range (280 to 320 nm), but Maclnnis would like to see the range of a good UV filter extend up to 405 nm (visible blue begins at 420 nm). .......... .... ..i
. . . . . . . . . . . . N1
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passed recently calls for total cessation of production of chlorofluorocarbons by 1995. Even if that happens, we must still wait decades until the store of halogen atoms in the atmosphere is metabolized. In other words, we are committed to a long period of health surveillance, personal protection and responsible caution. But Rosenthal reminds physicians to advise their patients with caution: "We have to be terribly careful not to make patients into cancerphobes," he says.
Reference 1. Koh HK: Cutaneous melanoma. N Engl JMed 1991; 325: 171-179
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ENVIRONMENT * ENVIRONNEMENT
Ms and ozone depleti*on: Be careful not to turn patients into "cancerphobes"
Peter P. Morgan, MD, DPH
E arly in February Jean Charest, the federal environment minister, reacted strongly to reports from US researchers that the ozone layer over the northern hemisphere could be reduced by as much as 40% in late winter and early spring. He urged Canadians to avoid exposure to sunlight as much as possible and told parents not to let their children play in the sun. Although he modified this position somewhat a few days later, Charest made Canadians conscious, in the bluntest possible way, that ozone depletion could become a national health threat. In March, an Angus Reid poll indicated that the message was getting across - about two-thirds of respondents said they would take extra precautions against exposure to the sun this year by wearing extra clothing and using sunscreens. The ozone "hole" that is causing the concern (see sidebar) is predicted to fill over as Canadians enter their sunny season, but concern is still great enough that Peter Morgan is a CMAJ consulting editor. APRIL 15, 1992
Environment Canada will release since people who work outdoors weekly ozone bulletins. These do not have higher rates of melread like stock market reports, anoma than those who work intelling us whether the market has side. gone up or down but not how Canadian physicians, always many investors have been en- strong believers in preventive riched or ruined. medicine, are strong on the idea The major ozone-related fear that UV overexposure is a preis that ultraviolet (UV) light trig- ventable pathogen or copathogen. gers malignant melanoma, a can- Dr. Donald Rosenthal, an Ottawa cer that is both preventable and dermatologist, says his concern treatable, yet sometimes metasta- about melanoma begins with his sizes so early that the game is lost. sketch of a person with a high-risk In the US, "the incidence of mela- profile: a blond, blue-eyed person noma has almost tripled in the who burns easily, has many dyslast four decades, and is growing plastic moles and a positive famifaster than that of any other can- ly history. Repeated quick suncer."' burns further increase the risk, Most Nordic countries report while a slow tan can be protective. a steady annual rise of about 5% Immunosuppressed patients, he in melanoma incidence in the past adds, may be running an even 40 years (World Health Organiza- greater risk - there is the possition, Press Release, Feb. 11, bility that UV light itself may 1992). In Canada, melanoma has affect the immune system adincreased at almost the same pace, versely. with 3000 cases and about 540 Dr. Lawrence Hurst, a plastic deaths now being reported yearly. surgeon in London, Ont., finds Although case reporting is far that he is operating on a growing from complete, at least 45 000 number of patients with melanononmalignant skin cancers occur mas and basal-cell and squamouseach year as well. However, as cell carcinomas; 95% of his referKoh' notes, the case against UV rals are from dermatologists, who radiation is not ironclad. The epi- in turn are confirming dysplastic demiologic and experimental evi- moles or melanomas on patients dence is somewhat conflicted, referred to them by family practiCAN MED ASSOC J 1992; 146 (8)
1397
tioners. His advice: "You can prevent 50% of lifetime UV exposure by adequate protection against excessive exposure to sunlight before age 18." Although pediatricians rarely see a case of melanoma, they are strongly prevention oriented. "I'm taking a much more aggressive policy in advising patients," observes Dr. Stanley Kardash of Ottawa. He recommends an industrial-strength sun blocker (with a blocking factor of 29 to 35), and that light clothing be worn on the beach.
Dr. William James agrees. "I bring it up a lot with parents," says James, a pediatrician at the Children's Hospital of Eastern Ontario in Ottawa. He says children should receive especially strong protection between 11 am and 2 pm, and suggests that a high-density blocker be put on 30 minutes before a child goes outside to play. Although the ozone issue received saturation media coverage during the winter, as the days lengthened there seemed to be little or no patient panic about I:- :-.:-.:....:..: .:..:..:...,.C:..:......:.. .;. ...
:!..'........::.:....-..-...: .;:....;... .:..".:....;:..:...
UV exposure. The American Academy of Dermatology, which has screened more than 358 000 people for skin cancer in recent years, says it has received few calls from citizens, but many from reporters, in response to ozonehole stories. Rosenthal is facing a growing number of questions about melanoma, but says he is still much more likely to bring up the subject of protection against the sun than his patients. Sunburn may prove to be the only stimulus that will heighten patients' 1. :. :
::.:..:...:.::.::.::.::.:j f,;:.;!.; :-
.;
.:: .....
*:...
1398
CAN MED ASSOC J 1992; 146 (8)
:.
LE 1 5 AVRIL 1992
Widely advertised UV filtering sunglasses may perform as advertised, blocking all the UV radiation in its target range, but still may not cover the entire UV range. And labels can be misleading; unscrupulous vendors can buy impressive labels to affix to low-quality glasses. Dr. Dario Lorenzetti of Montreal, current president of the Canadian Ophthalmological Society, adds that ocular melanoma has not been shown to be related to UV exposure. There seems to be little we can do about the capricious thinning of the ozone layer, at least at present. Down here on earth, prevention is the key word. The "Montreal Protocol" that was
health concern, he added. UV radiation can also damage another epidermal organ, the eye. It has been implicated in the formation of conjunctival pinguecula and pterygia, nuclear cataracts, age-related macular degeneration of the retina, and as a cause of a corneal disorder that revels in the name of Labrador keratopathy. Prevention is a bit tricky, says Dr. Brent Maclnnis, an Ottawa ophthalmologist. Almost all biologic damage is caused by radiation in the UV-B range (280 to 320 nm), but Maclnnis would like to see the range of a good UV filter extend up to 405 nm (visible blue begins at 420 nm). .......... .... ..i
. . . . . . . . . . . . N1
,1
passed recently calls for total cessation of production of chlorofluorocarbons by 1995. Even if that happens, we must still wait decades until the store of halogen atoms in the atmosphere is metabolized. In other words, we are committed to a long period of health surveillance, personal protection and responsible caution. But Rosenthal reminds physicians to advise their patients with caution: "We have to be terribly careful not to make patients into cancerphobes," he says.
Reference 1. Koh HK: Cutaneous melanoma. N Engl JMed 1991; 325: 171-179
.1
M .r---..I
~ i ~ ~ ~ ~ ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 'h
.. ............
'-. l S[ pilw i-t p// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Jt
__.
effev re fro
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/U= = /I 1
___--\11 \~~~~~~~~~~~~~~~~~~~~~~~h'AnusoI*HC fne -zincl
. \qi|hreflreffOr°d wof IiQett101' 0114 itch 11C
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_M01U0.
Hi~~~~~~~~~~huh41111Ai~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~I~~11I APRIL 15, 1992
CAN MED ASSOC J 1992; 146 (8)
1399
