The global decrease in cancer mortality: trends and disparities

BACKGROUND

A decrease in cancer mortality has been reported in the United States, Europe, and other high-income regions during the last two decades. Whether similar trends apply to low-to-middle income countries-and globally-is unclear.

DESIGN

The aim of this descriptive study is to compare cancer mortality in all countries with high- or intermediate-quality data on death certificates according to the World Health Organization (WHO) mortality database for the years 2000 through 2010. We included 60 countries in the analysis and calculated age-adjusted mortality rates for all cancer combined and for the commonest cancers worldwide: lung, stomach, breast, colorectal, uterine, and prostate.

RESULTS

A decrease in overall cancer mortality rate of ∼1% per year was observed in higher and lower income regions and in both sexes. In 2010, 696 000 cancer deaths were avoided on a global scale compared with 2000 rates (426 000 in men, 271 000 in women). However, the mortality of liver cancer in both sexes and lung cancer in females increased in many countries'.

CONCLUSIONS

The individual risk of dying from cancer decreased in all countries with reliable data. This decrease was chiefly due to favorable trends in the commonest specific cancers. Liver cancer in both sexes and lung cancer in women, which show increasing mortality rates, constitute a priority for prevention and further research.

Head and neck cancer prevention: from primary prevention to impact of clinicians on reducing burden

Survival from head and neck cancers (HNCs) of the lip, oral cavity, pharynx, and larynx has increased by 10% over the past few decades. Little over half of patients who develop HNCs will survive beyond 5 years. Survival is lower for individuals in many countries where traditional risk factors such as tobacco smoking, alcohol drinking, and betel quid chewing are highly prevalent but tertiary health care center access is limited or unavailable. Early diagnosis of HNC is the most important prognostic factor for each tumor site. Molecular-based research on HNC tumors holds promise for early stage detection, screening, vaccination, disease follow-up, and progression. Future investments for HNC control must consider both effectiveness and sustainability for both high- and low-resource countries alike, with priority toward risk factor prevention and earlier diagnosis.

The role of oral hygiene in head and neck cancer: results from International Head and Neck Cancer Epidemiology (INHANCE) consortium

BACKGROUND

Poor oral hygiene has been proposed to contribute to head and neck cancer (HNC) risk, although causality and independency of some indicators are uncertain. This study investigates the relationship of five oral hygiene indicators with incident HNCs.

METHODS

In a pooled analysis of 8925 HNC cases and 12 527 controls from 13 studies participating in the International Head and Neck Cancer Epidemiology Consortium, comparable data on good oral hygiene indicators were harmonized. These included: no denture wear, no gum disease (or bleeding), <5 missing teeth, tooth brushing at least daily, and visiting a dentist ≥once a year. Logistic regression was used to estimate the effects of each oral hygiene indicator and cumulative score on HNC risk, adjusting for tobacco smoking and alcohol consumption.

RESULTS

Inverse associations with any HNC, in the hypothesized direction, were observed for <5 missing teeth [odds ratio (OR) = 0.78; 95% confidence interval (CI) 0.74, 0.82], annual dentist visit (OR = 0.82; 95% CI 0.78, 0.87), daily tooth brushing (OR = 0.83, 95% CI 0.79, 0.88), and no gum disease (OR = 0.94; 95% CI 0.89, 0.99), and no association was observed for wearing dentures. These associations were relatively consistent across specific cancer sites, especially for tooth brushing and dentist visits. The population attributable fraction for ≤ 2 out of 5 good oral hygiene indicators was 8.9% (95% CI 3.3%, 14%) for oral cavity cancer.

CONCLUSION

Good oral hygiene, as characterized by few missing teeth, annual dentist visits, and daily tooth brushing, may modestly reduce the risk of HNC.

Cancer mortality in the elderly in 11 countries worldwide, 1970-2015

BACKGROUND

Population ageing results in an increasing cancer burden in the elderly. We aimed to evaluate time-trends in cancer mortality for adults aged 65 and over for 17 major cancer types and all cancers combined in 11 countries worldwide over the period 1970-2015.

MATERIALS AND METHODS

We obtained cancer death certification and population figures from the WHO and PAHO databases. We computed age-standardised (world standard population) rates for individuals aged 65 and over, and applied joinpoint regression models.

RESULTS

Age-standardised mortality rates for all cancers combined showed a heterogeneous, but widespread decline. Lung cancer mortality rates have been decreasing among men, and increasing among women. Pancreatic cancer had unfavourable trends in all countries for both sexes. Despite variability across countries, other tobacco-related cancers (except kidney) showed overall favourable trends, except in Poland and Russia. Age-standardised mortality rates from stomach cancer have been declining in all countries for both sexes. Colorectal mortality has been declining, except in Poland and Russia. Liver cancer mortality increased in all countries, except in Japan, France and Italy, which had the highest rates in the past. Breast cancer mortality decreased for most countries, except for Japan, Poland and Russia. Trends for age-standardised uterine cancer rates in the USA, Canada and the UK were increasing over the last decade. Ovarian cancer rates showed declines in most countries. With the exception of Russia, prostate cancer rates showed overall declines. Lymphoid neoplasms rates have been declining in both sexes, except in Poland and Russia.

CONCLUSION

Over the last decades, age-standardised cancer mortality in the elderly has been decreasing in major countries worldwide and for major cancer sites, with the major exception of lung and uterine cancer in women and liver, pancreatic and kidney cancers in both sexes. Cancer mortality for the elderly in central and eastern Europe remains comparatively high.

Comparison of Two Information Sources for Cause-of-Death Follow-up in the Russian Federation: The Asbest Chrysotile Cohort Study

BACKGROUND

The Asbest chrysotile cohort was set up in Asbest town, Sverdlovsk oblast, Russian Federation, among the current and former workforce of the world's largest operating chrysotile mine and its processing mills, to investigate cancer risk in relation to occupational exposure to chrysotile.

OBJECTIVES

The cohort of 35,837 people was followed-up for mortality using cause-of-death information from official death certificates issued by the Civil Act Registration Office (ZAGS) of Sverdlovsk oblast from 1976 to 2015. Data were also retrieved from the electronic cause-of-death registry of the Medical Information Analytical Centre (MIAC) of Sverdlovsk oblast, which was launched in 1990 and operates independently of ZAGS. The objectives were to compare the completeness of record linkage (RL) with ZAGS and with MIAC, and to compare the agreement of cause-of-death information obtained from ZAGS and from MIAC, with a focus on malignant neoplasms.

METHODS

RL completeness of identifying cohort members in ZAGS and in MIAC was compared for the period 1990 to 2015. In the next step, for the comparison of the retrieved cause-of-death information, 5,463 deaths (1,009 from cancer) were used that were registered in 2002 to 2015, when causes of death were coded using International Statistical Classification of Diseases and Related Health Problems, 10th revision (ICD-10) nomenclature by MIAC. For ZAGS, original cause-of-death text from the death certificates was obtained and then coded according to ICD-10 by the International Agency for Research on Cancer/World Health Organization (IARC/WHO). Agreement was evaluated at various levels of detail, and reasons for any disagreements between the MIAC and the IARC/WHO ICD-10-coded cancer diagnosis were systematically explored.

RESULTS

A total of 10,886 deaths were obtained from all avenues of follow-up for the period 1990 to 2015 in the cohort; 10,816 (99.4%) of these were found in ZAGS. This percentage was 88.3% if only automated deterministic RL was used and 99.4% when deterministic RL was complemented with manual searches of cohort members. Comparison of the cause-of-death information showed agreement of 97.9% at the ICD-10 main group level between ZAGS (coded by IARC/WHO) and MIAC. Of 1,009 cancer deaths, 679 (67.3%) cases had identical coding, 258 (25.6%) cases corresponded at the three-character ICD-10 level, 36 (3.6%) had codes that were within the same anatomical or morphological cluster, and for only 36 (3.6%) cases were major discrepancies identified. Altogether, the agreement between IARC/WHO coding of cause-of-death information from ZAGS and MIAC coding of malignant neoplasms was therefore 96.4%.

CONCLUSIONS

RL completeness and agreement of cause-of-death information obtained from ZAGS and from MIAC were both very high. This is reassuring for the quality of cancer mortality follow-up of the Asbest chrysotile cohort. For future epidemiological studies in the Russian Federation, ZAGS appears to be a reliable information source for mortality follow-up, if the automated RL is complemented with manual searches of cohort members. MIAC is a good resource for prospective studies.