Research topic

Global Cancer Incidence and Screening

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Research papers

2016 · JAMA Oncology · 6,329 citations

Global, Regional, and National Cancer Incidence, Mortality, Years of Life Lost, Years Lived With Disability, and Disability-Adjusted Life-years for 32 Cancer Groups, 1990 to 2015

IMPORTANCE: Cancer is the second leading cause of death worldwide. Current estimates on the burden of cancer are needed for cancer control planning. OBJECTIVE: To estimate mortality, incidence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs) for 32 cancers in 195 countries and territories from 1990 to 2015. EVIDENCE REVIEW: Cancer mortality was estimated using vital registration system data, cancer registry incidence data (transformed to mortality estimates using separately estimated mortality to incidence [MI] ratios), and verbal autopsy data. Cancer incidence was calculated by dividing mortality estimates through the modeled MI ratios. To calculate cancer prevalence, MI ratios were used to model survival. To calculate YLDs, prevalence estimates were multiplied by disability weights. The YLLs were estimated by multiplying age-specific cancer deaths by the reference life expectancy. DALYs were estimated as the sum of YLDs and YLLs. A sociodemographic index (SDI) was created for each location based on income per capita, educational attainment, and fertility. Countries were categorized by SDI quintiles to summarize results. FINDINGS: In 2015, there were 17.5 million cancer cases worldwide and 8.7 million deaths. Between 2005 and 2015, cancer cases increased by 33%, with population aging contributing 16%, population growth 13%, and changes in age-specific rates contributing 4%. For men, the most common cancer globally was prostate cancer (1.6 million cases). Tracheal, bronchus, and lung cancer was the leading cause of cancer deaths and DALYs in men (1.2 million deaths and 25.9 million DALYs). For women, the most common cancer was breast cancer (2.4 million cases). Breast cancer was also the leading cause of cancer deaths and DALYs for women (523 000 deaths and 15.1 million DALYs). Overall, cancer caused 208.3 million DALYs worldwide in 2015 for both sexes combined. Between 2005 and 2015, age-standardized incidence rates for all cancers combined increased in 174 of 195 countries or territories. Age-standardized death rates (ASDRs) for all cancers combined decreased within that timeframe in 140 of 195 countries or territories. Countries with an increase in the ASDR due to all cancers were largely located on the African continent. Of all cancers, deaths between 2005 and 2015 decreased significantly for Hodgkin lymphoma (-6.1% [95% uncertainty interval (UI), -10.6% to -1.3%]). The number of deaths also decreased for esophageal cancer, stomach cancer, and chronic myeloid leukemia, although these results were not statistically significant. CONCLUSION AND RELEVANCE: As part of the epidemiological transition, cancer incidence is expected to increase in the future, further straining limited health care resources. Appropriate allocation of resources for cancer prevention, early diagnosis, and curative and palliative care requires detailed knowledge of the local burden of cancer. The GBD 2015 study results demonstrate that progress is possible in the war against cancer. However, the major findings also highlight an unmet need for cancer prevention efforts, including tobacco control, vaccination, and the promotion of physical activity and a healthy diet.

2002 · Modern Pathology · 47 citations

Proliferation in African Breast Cancer: Biology and Prognostication in Nigerian Breast Cancer Material

Three hundred cases of invasive breast carcinoma from the University of Calabar Teaching Hospital, Nigeria were subjected to evaluation of proliferative activity by mitotic counts. The prognostic significance and association with other prognostic factors were evaluated. The mitotic activity was expressed as mitotic activity index (MAI), and standardized mitotic index (SMI). Pearson's correlation and univariate and multivariate Cox's regression were used. The mean follow-up time was 25.9 months. The mean values of SMI and MAI were 42.6 mitotic figures per square millimeter and 30.5 mitotic figures per 10 high-power fields, respectively, and these were much higher than values reported for Europe or other Western countries. The SMI had a positive correlation with tumor size (r = 0.31, P <.0001), histologic grade (r = 0.68, P <.0001), nuclear area (r = 0.45, P <.0001), and negative correlation with fraction of fields with tubular differentiation (FTD; r = -0.56, P = <0.0001). There was no statistically significant difference in the mitotic activity between the postmenopausal and the premenopausal patients. Also, lymph node-positive patients had higher counts than did lymph node-negative patients. Earlier determined grading associated decision thresholds divided the patients into groups of favorable and unfavorable prognosis. However, the statistically optimal thresholds for Nigerian material were different (32 and 92 mitotic figures per square millimeter for SMI). Tumor size of 5 cm, SMI, and MAI were independent prognostic factors. Nigerian breast cancers are high-grade, high-stage, and high-proliferating cancers occurring in a younger population than those of the Western countries. Proliferation is also more active. Evaluation of SMI or MAI can improve the distinction between aggressive and less aggressive variants of breast cancer.