Kidney and bladder cancer in Inuit 1969-1988

International variations in childhood cancer in indigenous populations: a systematic review

Although the cancer burden in indigenous children has been reported in some countries, up to now, no international comparison has been made. We therefore aimed to assess the available evidence of the burden of childhood cancer in indigenous populations. We did a systematic review of reports on cancer incidence, mortality, and survival in indigenous children worldwide. Our findings highlight the paucity of accessible information and advocate the pressing need for data by indigenous status in countries where population-based cancer registries are established. The true extent of disparities between the burden in the indigenous community needs to be measured so that targeted programmes for cancer control can be planned and implemented.

Cancer patterns in Inuit Nunangat: 1998-2007

OBJECTIVES

To compare cancer incidence patterns between residents of Inuit Nunangat and the rest of Canada.

STUDY DESIGN

Cancer cases were geographically linked to either Inuit Nunangat or the rest of Canada using postal codes or other geographic information. Population estimates were derived from the 2001 and 2006 censuses.

METHODS

Cancer cases were combined from 1998 to 2007 for Inuit Nunangat and the rest of Canada. Age-standardised incidence rates were calculated for all site cancers and sub-sites by sex. Standardised rate ratios between these 2 areas were calculated for all site cancers and sub-sites.

RESULTS

The age-standardised incidence rate for all cancer sites (1998-2007) was 14% lower for the Inuit Nunangat male population and 29% higher for the female population by comparison to the rest of Canada. Cancers of the nasopharynx, lung and bronchus, colorectal, stomach (males), and kidney and renal pelvis (females), were elevated in the Inuit Nunangat population compared to the rest of Canada, whereas prostate and female breast cancers were lower in the Inuit Nunangat population.

CONCLUSIONS

Cancers with potentially modifiable risk factors, such as buccal cavity and pharynx, nasopharynx, lung and bronchus, and colorectal cancer were elevated in the Inuit Nunangat population compared to the rest of Canada. Besides greater smoking prevalence within Inuit Nunangat by comparison to the rest of Canada, distinct socioeconomic characteristics between respective area populations including housing, and income may have contributed to incidence differentials. This study demonstrated that a geographic approach can be used in cancer surveillance when populations of interest are spatially distinguishable, and reside across distinct jurisdictions whose combined cancer registries will not completely provide information to identify the population of interest.

Lifestyle Factors, Exposures, Genetic Susceptibility, and Renal Cell Cancer Risk: A Review

Malignant kidney tumors account for approximately 2% of all new primary cancer cases diagnosed in the United States, with an estimated 30,000 cases occurring annually. Although a variety of agents, chemical and biological, have been implicated as causal agents in the development of renal cell carcinoma (RCC), the etiology remains enigmatic. The strongest association has been developed between cigarette smoking and renal cancer however consistent, positive associations between RCC and obesity, diabetes, and hypertension have also been reported. In addition, more recent investigations of familial kidney cancer syndromes indicate that a strong genetic component contributes to RCC development. Several genes have been identified through investigation of familial kidney cancer syndromes. This review article describes recent trends in RCC incidence and the currently identifiable etiological causes that account for approximately half of the RCC cases diagnoses. The remainder of this review then focuses on additional risk factors that have thus far not been well examined but may be helpful in explaining the increasing incidence trends and the geographic or racial variation observed nationally and worldwide.

Cancer patterns in Inuit populations

Inuit people inhabit the circumpolar region, with most living in Alaska, northwest Canada, and Greenland. Although malignant diseases were believed to be almost non-existent in Inuit populations during the beginning of the 20th century, the increasing life expectancy within these populations showed a distinct pattern, characterised by a high risk of Epstein-Barr virus-associated carcinomas of the nasopharynx and salivary glands, and a low risk of tumours common in white populations, including cancer of the prostate, testis, and haemopoietic system. Both genetic and environmental factors seem to be responsible for this pattern. During the second half of the 20th century, Inuit societies underwent major changes in lifestyle and living conditions, and the risk of lifestyle-associated tumours, especially cancers of the lung, colon, and breast, increased considerably after changes in smoking, diet, and reproductive factors. This Review will briefly summarise the current knowledge on cancer epidemiology in Inuit populations, with emphasis on the characteristic Inuit types of cancer.

Cancer in Circumpolar Inuit 1969-1988. A summary

The results of an international, collaborative study of cancer in Circumpolar Inuit in Greenland, Canada, Alaska and Russia are summarized. A total of 3 255 incident cancers were diagnosed from 1969 to 1988 among 85 000-110 000 individuals. Indirect standardization (SIR) based on comparison populations in Connecticut (USA), Canada and Denmark showed excess risk of cancer of the lung, nasopharynx, salivary glands, gallbladder and extrahepatic bile ducts in both sexes, of liver and stomach cancer in men, and renal and cervical cancer in women. Low risk was observed for cancer of the bladder, breast, endometrium and prostate, and for non-Hodgkin lymphoma, Hodgkin's disease, leukaemia, multiple myeloma and melanoma. Age-standardized incidence rates (ASRs) of cancer of lung, cervix, nasopharynx and salivary glands among Inuit were among the world's highest as were rates in women of oesophageal and renal cancer. Regional differences in ASRs within the Circumpolar area were observed for cancer of the cervix, lung, colon and rectum, liver, gallbladder and breast. The differences in the Inuit cancer incidence pattern to some extent reflect known variations in lifestyle, diet and other exposures, as well as implementation of cancer control measures. Future research addressing possible individual differences are needed to evaluate environmental and genetic factors in etiology and evaluate intervention studies.

Cancer among Circumpolar Inuit 1969-1988. Introduction and methods

Cancer incidence data for Circumpolar Inuit populations were developed and compiled from Greenland, Canada and Alaska from 1969 to 1988 to provide the largest possible base of data for documenting the unusual patterns of cancer previously reported for these populations. Cancer incidence and population data were transferred to the Danish Cancer Registry. Coded information from various ICD-classifications and codes for the basis of diagnosis were transformed to one format, enabling joint analysis. Standard descriptive analysis was carried out with presentation of number of cases, crude incidence rates (CR), age-standardized rates (world) (ASR), cumulative rates to age 64 years, and indirectly standardized ratios (SIR) to the populations of Connecticut (USA), Canada and Denmark. The resulting database can be used to support collaborative international research among the Inuit populations.