CANCER MORTALITY IN THE REGION OF THE COMMUNITY HEALTH DEPARTMENT OF THE LAKESHORE GENERAL HOSPITAL CANCER MORTALITY IN TOE REGION OF TOE GXMUJNITY HEALTH DEPAK1MENT OF TOE LAKESHORE GENERAL HOSPITAL SUBMITTED BY: DAVID MELNtfCHUK, M.D. * * Reçu \ u O I DSC NOVEMBER 1987
CANCER MORTALITY IN THE REGION OF THE COMMUNITY HEALTH DEPARTMENT OF THE LAKESHORE GENERAL HOSPITAL INTRODUCTION Cancer is a major cause of mortality in virtually all developed countries. Canada unfortunately is no exception to this rule. Within Canada, the province of Quebec, and Montreal (region 06A) in particular, have an elevated cancer mortality rate when compared to the country as a whole. The purpose of this brief report is to document the evolution of cancer mortality over a 15 yr. period (1969-1983) in the region of Montreal under the jurisdiction of the Community Health Department of the Lakeshore General Hospital. This information hopefully will be of some use in the designation of priorities and the development of programs to help reduce cancer mortality inflicted by this particular disease. It should be noted that some information regarding cancer mortality in this region is available 2. This study however will cover a longer time period and will treat this question in somewhat more detail.
METHODOLOGIC NOTES; The data for this study were provided by the CHD of the Centre hospitalier régional de l'outaouais who compiled them from data obtained from Statistics Canada 3. The mortality rate for the CHD region as a whole was not provided and this had to be calculated by the investigator. All other rates were included in the original data. All rates are age standardized. RESULTS : Overall Cancer Mortality The first place to begin is with a global outlook on the importance of cancer as a cause of death. As can be seen in Table 1, cancer as a percentage of all deaths has remained fairly stable over the time period in question if one considers the population as a whole. However, if one looks at the evolution of this index for the age group 25-74 (Table 2) it can be seen that for males cancer is becoming a relatively more important cause of death whereas for females in this age group it represents a more important cause of death but that its relative contribution to mortality has remained stable. These results however must be examined in the context of other data before any conclusions regarding their relative importance can be drawn. Another global index of interest is the evolution of the cancer mortality rate for the region over this period of time. As indicated in Table 3, there appears to be 2 distinct patterns of
evolution for cancer mortality. The male rate began at a relatively lower level than Montreal as a whole and during this time period remained fairly stable. The female rate of cancer death however has shown a tendency to decline over this period. It should be noted that then two trends were seen in the enitre 06A (Montrea) region. For the moment, there is no apparent explanation for these trends though it should be mentioned that they appear to be similar to what is occurring on a national level 4. An overall rate of cancer mortality however gives very limited information since cancer is an extremely hetereogeneous phenomen from a number of points of view. It is necessary therefore to look at specific cancer sites. Site Specific Cancer Mortality As can be seen in Table 4 over this period at time there has been relatively little variation in the five principal causes of cancer mortality for both males and females. These are also very similar to those of Montreal and the province of Quebec as a whole. Closer examination of the evolution of mortality due to cancer of these specific sites for the region of the CHD over time reveals that for the most part the absolute rates as well as their specific trends are very similar to that of the region of
Montreal and the province in general (see Tables 5 and 6). The major exception to this rule is that of male lung cancer which has shown a much lower rate of increase for the region of the CHD. Viewed as such it appears as if the area under our jurisdiction \ has had a relatively privileged existence with respect to cancer mortality. This however would not be an entirely correct assumption. An examination of various socio-demographic indices reveals that the territory under the jurisdiction of the CHD of the Lakeshore General Hospital is far from homogeneous 5. It is therefore important to examine cancer mortality in the different areas of the region. This can be adequately done by using the areas of jurisdiction for the various CLSC's of the region as the unit of classification. As can be seen by the accompanying map this division is fairly representative of the socio-economic diversity present in this region *. When one examines total cancer mortality rates for the subdivided CHD region a number of interesting trends emerge. The most striking of these is the diversity of experience in male cancer mortality in the area (see Table 7). As can be seen the male cancer mortality rate of Vieux La Chine and Pierrefonds has risen *The various rates for DDO should be examined with caution given its relatively small population.
whereas that of Lac St-Louis has fallen. As well the difference between Vieux La Chine and Lac St-Louis for the period is highly significant from a statistical point at view (p<.01). Female cancer mortality however was much more homogeneous and despite some apparent fluctuations no significant differences are present among the various subdivisions. To further clarify this situation it is imperative to examine the mortality rates by specific diagnosis. As indicated in Tables 8 and 9, the most striking difference bètween the subdivision is the evolution of male lung cancer mortality. This fairly well parallels the experience of total cancer mortality with an important rise seen in Vieux La Chine and a somewhat lesser rise in Pierrefonds coupled with a decline in Lac St-Louis. This however is the only form of major cancer (male or female) which exhibits this behaviour. As well it should be noted that this is markedly different them the evolution of female lung cancer mortality which has shown a relatively homogeneous rise throughout the region during this period. As stated above the other important causes of cancer mortality for both males and females do not manifest any important degree of heterogeneity in relation to the subdivisions in question. The trends in the mortality caused by the majority of these tumours, appear to be consistent with both provincial and national trends.
CONCLUSION: This study, though limited in nature, contains some interesting, if not completely original, findings. It has demonstrated that the most dynamic element of cancer mortality in this area is that attributable to cancer of the lung, in both males and females.,as well it demonstrates a number of well described characteristics of lung cancer epidemiology Of particular interest is the increasing rate of male lung cancer mortality in Vieux La Chine which is occurring while a decrease of lung cancer death is being seen in Lac St-Louis. This is consistent with observations in other countries demonstrating differential mortality from lung cancer according to socio-economic status 7. It is also interesting to note that females have not yet begun to manifest this sort of heterogeneity though this should be closely monitored since the increase in female lung cancer mortality is epidemiologically speaking a relatively recent phenomena and long term trends may not have begun to manifest themselves. In this regard it should be noted that in 1969 male lung cancer mortality was relatively similar in all areas of the region. In what concerns mortality from other forms of cancer the trends registered here are in general consistent with and of the some order of magnitude as those registered on a provincial and national level. As well they tend to be distributed in a relatively homogeneous fashion. This, in my opinion, indicates that there are no specific forms of cancer risk present in this
territory which would require special investigation at the level of the population as a whole. This of course does not mean that localized potentially important risks (such as specific industrial exposures) are entirely absent and thus. should not serve as an excuse to avoid investigating specific circumstances. This study also helps to demonstrate the potential difficulties associated with summary statistics from a region with a large amount of socio-demographic diversity. As shown here the mortality rates for the region as a whole distorted the true picture of what was occurring. Though this diversity is well known to the CHD, I feel that its importance should again be emphasized. This study has a number at obvious limitations. It confines itself solely to mortality and this does not permit any real comments about incidence. This is not an important point with many cancers since most are associated with high rates of mortality. However in some, such as cancer at the cervix, mortality is a somewhat imperfect index of the evolution of the disease 8. Another limitation is the nature of the study, and its source of data. This study, descriptive in nature, provides very few explanatory insights into the result, which were obtained. As well it is essentially based on reported death certification which is associated with a number of well known difficulties
\ Despite these problems, I feel that the information generated provides additional support for one of the important recent undertakings of the CHD, namely an anti-smoking campaign. As well I think it should provide some guidance in the development of priorities and the evaluation of other programs designed to reduce the cancer related mortality.
REFERENCES 1) Statistiques Canadiennes sur le cancer, 1987, Canadian Sancer Society 2) TREMBLAY, Micheline; Etude de la mortalité (1976-81), Internai Document of the CHD of the Lakeshore General Hospital, 1985 3) CHD Centre hospitalier Régional de l'outaouais, Projet d 1 outils de surveillance en santé communautaire. This document should be consulted on the methodology of data collection and analysis. 4) Statistiques Canadiennes sur le cancer, 1987, Canadian Cancer Society 5) BRAIS, Yanina et Tremblay, Daniel? Dossier sociodémographique 1981, Internai document at the CHD of the Lakeshore General Hospital. 6) LAST, J. (editor); Public Health and Preventitive Medicine, lie edition, page 1149-50. 7) MARMOT, M.G. ; McDowell, M.E.; Mortality decline and widening social inequalities, Lancet August 2, 1986 pages 274-276. 8) STARREVELS, A.A.; The Latency Period of Carcinoma-in-Situ, Obstet. Gynecol., 62:348, 1983. 9) SIRKEN, M. et al.; The quality of cause-of-death statistics, AJ PH, Vol. 77, No. 2, page 137.
TABLE 1 CANCER AS A PERCENTAGE OF TOTAL DEATHS, ALL AGES CHD TERRITORY Males 23,0% 24,0% 27,6% Females 26,5% 27,3% 27,8% TABLE 2 CANCER AS A PERCENTAGE OF TOTAL DEATHS. AGES 25-74 CHD TERRITORY Males 27,9% 26,7% 31,4% Females 41,8% 39,8% 41,2% TABLE 3 ALL CANCER MORTALITY RATES (PER 100 000). ALL AGES. MALE DSC MONTREAL PROVINCE 189,6 219 199,2 190,4 215 201,5 192,0 216 207,6 ALL CANCER MORTALITY RATES (PER 100 000). ALL AGES. FEMALES 132,7 144,4 134,7 128,6 132,7 123,7 125,5 125,9 120,0
LEADING CAUSES OF CANCER DEATH IN THE REGION OF THE CHD. MALE. ALL AGES (Per 100.000) Lung(56,2) Colorectal(26,4) Esophagus and E.N.T.(14,5) Prostate(13.4) Lymphoma(11,9) Lung(64,2) Colorectal(29) Prostate(13,4) Esophagus and E.N.T. (11,0) Stomach(10,8) Lung(67,4) Colorectal(24,4) Prostate(15,4) Esophagus and E.N.T. (11,2) Pancreas(10,1) LEADING CAUSES AT CANCER DEATH IN THE REGION OF THE CHD. FEMALE. ALL AGES (Per 100.000) Breast(31) Colorectal(21,6) Misc. G.U.(15,2) Lung(9,2) Stomach(8,3) Breast(28,3) Colorectal(21,7) Misc. G.U.(17,2) Lung(10,9) Pancreas(6) Breast(25,1) Colorectal(21,2) Lung(15,2) Misc. G.U.(11,5) Lymphoma(8,5)
TABLE 2933 EVOLUTION OF SPECIFIC CANCER MORTALITY RATES (PER 100 000V FOR THE CHD. MONTREAL AND THE PROVINCE. 1969-83, MALE, ALL AGES LUNG CHD 56,2 64,2 67,4 Montreal 66,6 73,5 80,0 Province 55,1 66,4 76,3 COLORECTAL CHD 26,4 29,0 24,4 Montreal 30,8 28,6 27,2 Province 28,2 25,4 24,7 ESOPHAGUS AND E.N.T. CHD 14,5 11,0 11,2 Montreal 15,1 12,8 11,6 Province 12,5.11,2 10,0
J TABLE 5 (CONTINUED) PANCREAS!CHD 9,6 7,3 10,1 Montreal 11,4 9,8 10,8 Province 10,5 9,9 11,1 PROSTATE CHD 13,4 13,4 15,6 Montreal 20,2 17,2 17,1 Province 19,6 17,9 17,1 LYMPHOMA CHD 11,9 7,8 10,1 Montreal 10,3. 9,6 9,4 Province 9,0 9,2 9,2
TABLE 6 EVOLUTION OF SPECIFIC CANCER MORTALITY RATES (PER 100 0001 FOR THE CHD. MONTREAL AND PROVINCE. 1969-83. FEMALE. ALL AGES BREAST CHD 31,0 28,3 25,1 Montreal 31,0 29,2 26,6 Province 28,6 26,7 25,1 COLORECTAL CHD 21,6 21,7 21,2 Montreal 27,0 22,3 19,3 Province 24,6 21,3 18,7 LUNG CHD 9,2 10,9 15,2 Montreal 10,1 12.4 16,4 Province 8,5 10.5 14,7
TABLE 6 (CONTINUED) MISC. G.U. CHD 15,2 17,2 11,5 Montreal 15,6 13,4 11,5 Province 14,4 12,4 11,1 PANCREAS CHD 5,5 6,0 7,2 Montreal 6,3 6,9 6,2 Province 5,9 6,1 6,2 CERVIX CHD 7,1 2,6 1,5 Montreal 6,9 3,9 3,2 Province 5,8 3,3 2,7
I TABLE 7 ALL CANCER MORTALITY RATES (PER 100 000) FOR SUBDIVISIONS AT THE CHD. MALE. ALL AGES Vieux La Chine 201,5 200,0 234,1 Pierrefonds 144,7 170,2 204,6 *Dollard-des-Ormeaux 353,8 163, 6 215,0 Lac St-Louis 184,0 196,2 137,2 ALL CANCER MORTALITY RATES (PER 100 0001 FOR SUBDIVISIONS AT THE CHD. FEMALE. ALL AGES Vieux La Chine 133,8 118,6 124,7 Pierrefonds 138,1 133,2 121,6 *Dollard-des-Ormeaux 206,4 150,0 137,0 Lac St-Louis 116,3 136,4 126,1 * Note that the rates for Dollard-des-Ormeaux should be regarded with circumspection since it has a relatively small population base which tends to make its rates somewhat unstable.
TABLE 8 EVOLUTION OF SPECIFIC CANCER MORTALITY RATES (PER 100 000) FOR SUBDIVISIONS AT THE CHD. MALE. ALL AGES LUNG Vieux La Chine 57.4 70,2 88,4 Pierrefonds 50.5 67.6 69,3 *Dollard-des-Ormeaux 210,2 45.7 104,3 Lac St-Louis 50,2 53,5 42,1 ESOPHAGES AND E.N.T. Vieux La Chine 15,3 8,8 13.0 Pierrefonds 6,0 11,7 11,7 *Dollard-des-Ormeaux 0,0 8,3 3,8 Lac St-Louis 19,9 11,2 10.1 PROSTATE Vieux La Chine 12, 5 20,2 19,7 Pierrefonds 19.2 14.6 24.1 *Dollard-des-Ormeaux 0,0 11,9 21.2 Lac St-Louis 20.3 12.7 12,7
TABLE 8 (CONTINUED) COLORECTAL Vieux La Chine Pierrefonds *Dollard-des-Ormeaux Lac St-Louis 30.2 30,7 31,8 19.3 15,7 30,9 11,1 35,7 20,2 29,0 39,0 24,8 PANCREAS Vieux La Chine 12.5 5,7 10,8 Pierrefonds 4,6 5,6 8,3 *Dollard-des-Ormeaux 72,7 8,5 5,1 Lac St-Louis 5.6 8,0 10,4 LYMPHOMA Vieux La Chine 10.6 7.7 11,3 Pierrefonds 6.7 3.8 10,2 *Dollard-des-Ormeaux 16,9 1.9 5,7 Lac St-Louis 10,9 7,8 9,9 * See comment on table 7.
TABLE 9 EVOLUTION OF SPECIFIC CANCER MORTALITY RATES (PER 100 0001 FOR SUBDIVISIONS AT THE CHD. FEMALE. ALL AGES BREAST Vieux La Chine 26,3 24.1 23.4 Pierrefonds 37,6 27,8 26,9 *Dollard-des-Ormeaux 32,5 28.2 28,1 Lac St-Louis 27,9 31,5 22.5 COLORECTAL Vieux La Chine 25.6 23,2 25,3 Pierrefonds 21,5 29.0 20,2 *Dollard-des-Ormeaux 35.7 19,6 23,2 Lac St-Louis 14.8 17.1 22,5 LUNG Vieux La Chine 8.5 10,8 14,2 Pierrefonds 5,0 11,5 16,0 *Dollard-des-Ormeaux 32,6 10,4 16,9 Lac St-Louis 6.6 11,3 16,2
TABLE 9 (CONTINUED! MISC. G.U. Vieux La Chine Pierrefonds *Dollard-des-Ormeaux Lac St-Louis 14,4 19,4 11,7 15,6 18,1 10,5 32.4 11,6 11,8 13.5 14,5 13,0 PANCREAS Vieux La Chine Pierrefonds *Dollard-des-Ormeaux Lac St-Louis 7.1 4,9 7,5 4,6 6,2 5,6 0,0 5,8 10,0 4,6 8,7 6,7 CERVIX Vieux La Chine Pierrefonds *Dollard-des-Ormeaux Lac St-Louis 5.2 2,8 1,1 9.4 1,8 2,7 15,3 3,2 2,2 8.5 2,3 1,0 * See comment on table 7.
Cancer morl.ïlity in Che region of the Community Health Department of the Lakeshore General Hospit Melnychuk, David DATS MOM