Cancer in sub-Saharan Africa in 2020: a review of current estimates of the national burden, data gaps, and future needs

BACKGROUND

With the cancer burden rising in sub-Saharan Africa, countries in the region need surveillance systems to measure the magnitude of the problem and monitor progress in cancer control planning. Based on the national estimates built from data provided by cancer registries in sub-Saharan Africa, we summarise key patterns of the regional burden and argue for investments in locally produced data.

METHODS

To present national estimates of the cancer incidence and mortality burden in sub-Saharan Africa countries, new cancer cases and deaths were extracted from International Agency for Research on Cancers' GLOBOCAN database for the year 2020. Given weak vital statistics systems, almost all of the information on the cancer burden in sub-Saharan Africa was derived from population-based cancer registries. Of the 48 countries included in GLOBOCAN (national populations must be larger than 150 000 inhabitants in 2020), relatively recent cancer registry data (up to 2019) were directly used to produce national incidence estimates in 25 countries, while the absence of such data for 16 meant that estimates were based on data from neighbouring countries. Tables and figures present the estimated numbers of new cases and deaths, as well as age-standardised (incidence or mortality) rates per 100 000 person-years and the cumulative risk of developing or dying from cancer before the age of 75 years.

FINDINGS

801 392 new cancer cases and 520 158 cancer deaths were estimated to have occurred in sub-Saharan Africa in 2020. Cancers of the breast (129 400 female cases) and cervix (110 300 cases) were responsible for three in ten of the cancers diagnosed in both sexes. Breast and cervical cancer were the most common cancers, ranking first in 28 and 19 countries, respectively. In men, prostate cancer led in terms of incidence (77 300 cases), followed by liver cancer (24 700 cases) and colorectal cancer (23 400 cases). Prostate cancer was the leading incident cancer in men in 40 sub-Saharan Africa countries. The risk of a woman in sub-Saharan Africa developing cancer by the age of 75 years was 14·1%, with breast cancer (4·1%) and cervical cancer (3·5%) responsible for half of this risk. For men, the corresponding cumulative incidence was lower (12·2%), with prostate cancer responsible for a third of this risk (4·2%). Cervical cancer was the leading form of cancer death among women in 27 countries, followed by breast cancer (21 countries). Prostate cancer led as the most common type of cancer death in 26 countries, with liver cancer ranking second (11 countries).

INTERPRETATION

The estimates indicate substantial geographical variations in the major cancers in sub-Saharan Africa. Rational cancer control planning requires capacity to be built for data production, analysis, and interpretation within the countries themselves. Cancer registries provide important information in this respect and should be prioritised for sustainable investment in the region.

FUNDING

None.

Five ways to improve international comparisons of cancer survival: lessons learned from ICBP SURVMARK-2

BACKGROUND

Comparisons of population-based cancer survival between countries are important to benchmark the overall effectiveness of cancer management. The International Cancer Benchmarking Partnership (ICBP) Survmark-2 study aims to compare survival in seven high-income countries across eight cancer sites and explore reasons for the observed differences. A critical aspect in ensuring comparability in the reported survival estimates are similarities in practice across cancer registries. While ICBP Survmark-2 has shown these differences are unlikely to explain the observed differences in cancer-specific survival between countries, it is important to keep in mind potential biases linked to registry practice and understand their likely impact.

METHODS

Based on experiences gained within ICBP Survmark-2, we have developed a set of recommendations that seek to optimally harmonise cancer registry datasets to improve future benchmarking exercises.

RESULTS

Our recommendations stem from considering the impact on cancer survival estimates in five key areas: (1) the completeness of the registry and the availability of registration sources; (2) the inclusion of death certification as a source of identifying cases; (3) the specification of the date of incidence; (4) the approach to handling multiple primary tumours and (5) the quality of linkage of cases to the deaths register.

CONCLUSION

These recommendations seek to improve comparability whilst maintaining the opportunity to understand and act upon international variations in outcomes among cancer patients.

A way to explore the existence of "immortals" in cancer registry data - An illustration using data from ICBP SURVMARK-2

BACKGROUND

Accurately recorded vital status of individuals is essential when estimating cancer patient survival. When deaths are ascertained by linkage with vital statistics registers, some may be missed, and such individuals will wrongly appear to be long-term survivors, and survival will be overestimated. Interval-specific relative survival that levels off above one indicates that the survival among the cancer patients is better than expected, which could be due to the presence of immortals.

METHODS

We included colon cancer cases diagnosed in 1995-1999 within the 19 jurisdictions in seven countries participating in ICBP SURVMARK-2, with follow-up information available until end-2015. Interval-specific relative survival was estimated for each year following diagnosis, by country and age group at diagnosis.

RESULTS

The interval-specific relative survival levels off at 1 for all countries and age groups, with two exceptions: for the age group diagnosed at age 75 years and above in Ireland, and, to a lesser extent, in New Zealand.

CONCLUSION

Overall, a subset of immortals are not apparent in the early years within the ICBP SURVMARK-2 study, except for possibly in Ireland. We suggest this approach as one strategy of exploring the existence of immortals, and to be part of routine checks of cancer registry data.

Population-based cancer staging for oesophageal, gastric, and pancreatic cancer 2012-2014: International Cancer Benchmarking Partnership SurvMark-2

Cancer stage at diagnosis is important information for management and treatment of individual patients as well as in epidemiological studies to evaluate effectiveness of health care system in managing cancer patients. Population-based studies to examine international disparities on cancer survival by stage, however, has been challenging due to the lack of international standardization on recording stage information and variation in stage completeness across regions and countries. The International Cancer Benchmarking Partnership (ICBP) previously assessed the availability and comparability of staging information for colorectal, lung, female breast and ovarian cancers. Stage conversion algorithms were developed to aggregate and map all stage information into a single staging system to allow international comparison by stage at diagnosis. In this article, we developed stage conversion algorithms for three additional cancers, namely oesophageal, gastric and pancreatic cancers. We examined all stage information available, evaluated stage completeness, applied each stage conversion algorithm, and assessed the magnitude of misclassification using data from six Canadian cancer registries (Alberta, Manitoba, Newfoundland, Nova Scotia, Prince Edward Island and Saskatchewan). In addition, we discussed five recommendations for registries to improve international cancer survival comparison by stage: (a) improve collection and completeness of staging data; (b) promote a comparable definition for stage at diagnosis; (c) promote the use of a common stage classification system; (d) record versions of staging classifications and (e) use multiple data sources for valid staging data.

Development of paediatric non-stage prognosticator guidelines for population-based cancer registries and updates to the 2014 Toronto Paediatric Cancer Stage Guidelines

Population-based cancer registries (PBCRs) generate measures of cancer incidence and survival that are essential for cancer surveillance, research, and cancer control strategies. In 2014, the Toronto Paediatric Cancer Stage Guidelines were developed to standardise how PBCRs collect data on the stage at diagnosis for childhood cancer cases. These guidelines have been implemented in multiple jurisdictions worldwide to facilitate international comparative studies of incidence and outcome. Robust stratification by risk also requires data on key non-stage prognosticators (NSPs). Key experts and stakeholders used a modified Delphi approach to establish principles guiding paediatric cancer NSP data collection. With the use of these principles, recommendations were made on which NSPs should be collected for the major malignancies in children. The 2014 Toronto Stage Guidelines were also reviewed and updated where necessary. Wide adoption of the resultant Paediatric NSP Guidelines and updated Toronto Stage Guidelines will enhance the harmonisation and use of childhood cancer data provided by PBCRs.

Can different definitions of date of cancer incidence explain observed international variation in cancer survival? An ICBP SURVMARK-2 study

BACKGROUND

Differences in registration practices across population-based cancer registries may contribute to international variation in survival estimates. In particular, there are variations in recorded date of incidence (DOI) as cancer registries have access to different sources of information and use different rules to determine an official DOI. This study investigates the impact of different DOI rules on cancer survival estimates.

MATERIALS AND METHODS

Detailed data on dates of pathological confirmation and hospital admittance were collected from three registries participating in the ICBP SURVMARK-2 project (England, Northern Ireland and Norway). Multiple dates of incidence were determined for each cancer patient diagnosed during 2010-2014 by applying three sets of rules that prioritize either: a) histological date, b) hospital admittance date or c) the earliest date recorded. For each set of rules and registry, 1- and 5-year net survival were estimated for eight cancer sites (oesophagus, stomach, colon, rectum, liver, pancreas, lung and ovary).

RESULTS

The mean difference between different DOIs within a country and cancer site ranged from 0.1-23 days. The variation in 1- and 5-year net survival using different DOIs were generally small for all registries and cancer sites. Only for liver and pancreatic cancer in Norway and ovarian cancer in England, were larger 1-year survival differences, of 2-3 % found.

CONCLUSION

In the ongoing discussion of the comparability of survival estimates across registry populations, the use of different DOI definitions can be considered to have a very limited impact.

Cancer incidence in older adults in selected regions of sub-Saharan Africa, 2008-2012

Although the countries of Sub-Sharan Africa represent among the most rapidly growing and aging populations worldwide, no previous studies have examined the cancer patterns in older adults in the region as a means to inform cancer policies. Using data from Cancer Incidence in Five Continents, we describe recent patterns and trends in incidence rates for the major cancer sites in adults aged ≥60 years and in people aged 0-59 for comparison in four selected population-based cancer registries in Kenya (Nairobi), the Republic of South Africa (Eastern Cape Province), Uganda (Kyadondo country), and Zimbabwe (Harare blacks). Over the period 2008-2012, almost 9,000 new cancer cases were registered in older adults in the four populations, representing one-third of all cancer cases. Prostate and esophageal cancers were the leading cancer sites in older males, while breast, cervical and esophageal cancers were the most common among older females. Among younger people, Kaposi sarcoma and non-Hodgkin lymphoma were common. Over the past 20 years, incidence rates among older adults have increased in both sexes in Uganda and Zimbabwe while rates have stabilized among the younger age group. Among older adults, the largest rate increase was observed for breast cancer (estimated annual percentage change: 5% in each country) in females and for prostate cancer (6-7%) in males. Due to the specific needs of older adults, tailored considerations should be given to geriatric oncology when developing, funding and implementing national and regional cancer programmes.

Essential TNM: a registry tool to reduce gaps in cancer staging information

Accurate information on the extent of disease around the time of diagnosis is an important component of cancer care, in defining disease prognosis, and evaluating national and international cancer control policies. However, the collection of stage data by population-based cancer registries remains a challenge in both high-income and low and middle-income countries. We emphasise the lack of availability and comparability of staging information in many population-based cancer registries and propose Essential TNM, a simplified staging system for cancer registries when information on full Tumour, Node, Metastasis (TNM) is absent. Essential TNM aims at staging cancer in its most advanced disease form by summarising the extent of disease in the order of distant metastasis (M), regional lymph node involvement (N), and tumour size or extension, or both (T). Flowcharts and rules have been developed for coding these elements in breast, cervix, prostate, and colon cancers, and combining them into stage groups (I-IV) that correspond to those obtained by full TNM staging. Essential TNM is comparable to the Union for International Cancer Control TNM stage groups and is an alternative to providing staging information by the population-based cancer registries that complies with the objectives of the Global Initiative for Cancer Registry Development.

Cost of Operating Population-Based Cancer Registries: Results from 4 Sub-Saharan African Countries

Large differences exist in the coverage and quality of cancer surveillance systems across the world, with limited data currently available from low-resource settings. Information on the resources required to register cancer cases are needed in order for global, national, regional, and local stakeholders to adequately support cancer registry operations. The objective of this study is to estimate the cost of cancer registration and report the cost per cancer incident case, the cost per inhabitant in the area covered by the registry, and cost allocated to specific registry activities. The International Registry Costing Tool (IntRegCosting Tool) of the Centers for Disease Control and Prevention was used to assess the costs and resources used by 4 registries in sub-Saharan Africa (Zimbabwe, Uganda, Kenya, and Seychelles). The cost of registering a cancer case ranged from $9 to $96, with lower costs in low- and middle-income countries than in the high-income country. The cost of cancer registration at the population level is very low, ranging from 1 to 17 cents per person. The detailed cost information provided in this manuscript can help registries in in sub-Saharan Africa understand the cost of their registry operations and identify approaches to improve efficiency to meet program priorities. Furthermore, it provides additional evidence to inform funding and resource allocation decisions to advance cancer registration in the region.

Essential TNM: Evaluation of a Training Exercise in Sub-Saharan Africa

Information on cancer stage at diagnosis is largely missing or poorly documented among population-based cancer registries in sub-Saharan Africa (SSA). In an early field trial of Essential TNM staging, it was observed that some training was needed to enable cancer registrars to abstract the correct TNM from case records. In November 2018, the Addis Ababa City Cancer Registry hosted a training course attended by 17 participants from 16 cancer registries in SSA. The participants were asked to stage 16 cancer cases (from anonymized photocopies of case records obtained from the Global Initiative for Cancer Registry Development) before and after the training. The discrepancy of the stages from before and after were scored and compared. Results showed that there was a substantial improvement in the participants' performance after the training. The application of the Essential TNM staging system, with training in its use, would allow cancer registrars in SSA to abstract cancer stage at diagnosis in a clinically recognized format, which is crucial for cancer control and public health care policy making.

Estimating the global cancer incidence and mortality in 2018: GLOBOCAN sources and methods

Estimates of the worldwide incidence and mortality from 36 cancers and for all cancers combined for the year 2018 are now available in the GLOBOCAN 2018 database, compiled and disseminated by the International Agency for Research on Cancer (IARC). This paper reviews the sources and methods used in compiling the cancer statistics in 185 countries. The validity of the national estimates depends upon the representativeness of the source information, and to take into account possible sources of bias, uncertainty intervals are now provided for the estimated sex- and site-specific all-ages number of new cancer cases and cancer deaths. We briefly describe the key results globally and by world region. There were an estimated 18.1 million (95% UI: 17.5-18.7 million) new cases of cancer (17 million excluding non-melanoma skin cancer) and 9.6 million (95% UI: 9.3-9.8 million) deaths from cancer (9.5 million excluding non-melanoma skin cancer) worldwide in 2018.

Survival from childhood cancers in Eastern Africa: A population-based registry study

Cancers occurring in children in Africa are often underdiagnosed, or at best diagnosed late. As a result, survival is poor, even for cancers considered 'curable'. With limited population-level data, understanding the actual burden and survival from childhood cancers in Africa is difficult. In this study, we aimed at providing survival estimates for the most common types of cancers affecting children aged 0-14 years, in three population-based Eastern African registries; Harare, Zimbabwe (Kaposi sarcoma, Wilms tumour (WT), non-Hodgkin lymphoma (NHL), retinoblastoma, and acute lymphocytic leukaemia (ALL)), Kampala, Uganda (Burkitt lymphoma, Kaposi sarcoma, WT, and retinoblastoma), and Nairobi, Kenya (ALL, retinoblastoma, WT, Burkitt lymphoma, and Hodgkin lymphoma). We included cases diagnosed within the years 1998-2009 and followed up till the end of 2011. We estimated the observed and relative survival at 1, 3, and 5 years after diagnosis. We studied 627 individual patient records. Median follow-up ranged from 2.2 months for children with Kaposi sarcoma in Harare to 30.2 months for children with ALL in Nairobi. The proportion of children lost to follow-up was highest in the first year after diagnosis. In Harare and Kampala, the 5-year relative survival was <46% for all cancer types. The 5-year relative survival was best for children in Nairobi, though with wider confidence intervals. Survival from childhood cancers in Africa is still poor, even for cancers with good prognosis and potential for cure. Supporting cancer detection, treatment, and registration activities could help improve survival chances for children with cancers in Africa.

Cancer Mortality in Italian Migrants to Canada

The present study reports on the analysis of cancer mortality in Italian first-generation migrants resident in Canada, deceased in the period between 1964-1985 (5,801 males: 3,267 females). Mortality in migrants is compared to that of the host population as well as to that in the migrants’ country of origin. This is carried out both on a national level (Italy), and on a regional level with those regions that have made the greatest contribution to the Italian migratory flow (Southern Italy). Compared with the Canada-born population, significantly higher risks were evident for nasopharynx, stomach, liver and gallbladder tumors in migrants. Lower risks were observed for the oral cavity, esophagus, colon, rectum, pancreas (females), larynx, lung, melanoma, breast, ovary, prostate, bladder (females), and non-Hodgkin's lymphoma in migrants. This is consistent with that evidenced in the comparison between Italy and Canada. The data are discussed in relation to the results of other studies on Italian migrants and the prevalence of main risk factors.

Three-year cancer incidence in Blantyre, Malawi (2008-2010)

In this paper, we present incidence rates of different cancers calculated for the population of Blantyre, Malawi for the period 2008-2010, using data from the Malawi Cancer Registry. Active methods were used for case finding, with standard checks for accuracy and validity performed in CanReg 4. During this 3-year period, a total of 3,711 cases were registered comprising 1,643 men (an estimated age-standardized incidence rate (ASR) of 169.8 per 100,000) and 2,068 women (ASR 238.7 per 105 ). Kaposi sarcoma (KS) was the most common cancer in men (40.5% of all cancers in men; ASR 54.0 per 105 ) while cervical cancer was the commonest in women (33.3%; ASR 88.6 per 105 ). The incidence rates for esophageal cancer remain one of the highest in the world (ASR 30.9 per 100,000 in men, 22.1 per 100,000 in women). Incidence of cancer of the prostate is relatively low in Blantyre (5.1%; ASR 16.4 per 105 ), compared with elsewhere in Africa. In childhood, the cancer spectrum is dominated by Burkitt lymphoma (32.5% ASR 90.9 per 106 ) followed by Wilms tumor (11.3%; ASR 35.9 per 106 ) and pediatric KS (11.0%; ASR 31.1 per 106 ). The overall percentage of cases with histological verification was 47.5%, a slight improvement from 42.4% in late 1990s also indicating successful case finding outside laboratories.

Cancer of childhood in sub-Saharan Africa

Measurement of incidence rates of childhood cancer in Africa is difficult. The study 'Cancer of Childhood in sub Saharan Africa' brings together results from 16 population-based registries which, as members of the African Cancer Registry Network (AFCRN), have been evaluated as achieving adequate coverage of their target population. The cancers are classified according to the third revision of the International Classification of Childhood Cancer (ICCC-3) and recorded rates in Africa are compared with those in childhood populations in the UK, France, and the USA. It is clear that, in many centres, lack of adequate diagnostic and treatment facilities leads to under-diagnosis (and enumeration) of leukaemias and brain cancers. However, for several childhood cancers, incidence rates in Africa are higher than those in high-income countries. This applies to infection-related cancers such as Kaposi sarcoma, Burkitt lymphoma, Hodgkin lymphoma and hepatocellular carcinoma, and also to two common embryonal cancers - retinoblastoma and nephroblastoma. These (and other) observations are unlikely to be artefact, and are of considerable interest when considering possible aetiological factors, including ethnic differences in risk (and hence genetic/familial antecedents). The data reported are the most extensive so far available on the incidence of cancer in sub Saharan Africa, and clearly indicate the need for more resources to be devoted to cancer registration, especially in the childhood age range, as part of an overall programme to improve the availability of diagnosis and treatment of this group of cancers, many of which have-potentially-an excellent prognosis.

Long term effects of once-only flexible sigmoidoscopy screening after 17 years of follow-up: the UK Flexible Sigmoidoscopy Screening randomised controlled trial

BACKGROUND

Colorectal cancer is the third most common cancer worldwide. Previous analyses have only reported follow-up after flexible sigmoidoscopy for a maximum of 12 years. We aimed to examine colorectal cancer incidence and mortality after a single flexible sigmoidoscopy screening and 17 years of follow-up.

METHODS

In this multicentre randomised trial (UK Flexible Sigmoidoscopy Screening Trial), done between Nov 14, 1994, and March 30, 1999, 170 432 eligible men and women, who had indicated on a previous questionnaire that they would probably attend screening if invited, were randomly assigned (1:2) to an intervention group (offered flexible sigmoidoscopy screening) or a control group (not contacted). Randomisation was done centrally in blocks of 12, and stratified by trial centre, general practice, and household type. The nature of the intervention did not allow the staff to be masked to arm of the trial; however, randomisation was done in batches so that the control group and participants not yet randomised were unaware of their allocation status. The primary outcomes were incidence and mortality of colorectal cancer. Hazard ratios (HRs) and 95% CIs for colorectal cancer incidence and mortality were estimated for intention-to-treat and per-protocol analyses. The trial is registered with ISRCTN, number 28352761.

FINDINGS

Our cohort analysis included 170 034 people: 112 936 in the control group and 57 098 in the intervention group, 40 621 (71%) of whom were screened and 16 477 (29%) were not screened. During screening and a median of 17·1 years' follow-up, colorectal cancer was diagnosed in 1230 individuals in the intervention group and 3253 in the control group, and 353 individuals in the intervention group versus 996 individuals in the control group died from colorectal cancer. In intention-to-treat analyses, colorectal cancer incidence was reduced by 26% (HR 0·74 [95% CI 0·70-0·80]; p<0·0001) in the intervention group versus the control group and colorectal cancer mortality was reduced by 30% (0·70 [0·62-0·79]; p<0·0001) in the intervention group versus the control group. In per-protocol analyses, adjusted for non-compliance, colorectal cancer incidence and mortality were 35% (HR 0·65 [95% CI 0·59-0·71]) and 41% (0·59 [0·49-0·70]) lower in the screened group.

INTERPRETATION

A single flexible sigmoidoscopy continues to provide substantial protection from colorectal cancer diagnosis and death, with protection lasting at least 17 years.

FUNDING

National Institute for Health Research Efficacy and Mechanism Evaluation.

Cancer risks in Nairobi (2000-2014) by ethnic group

We investigated the ethnic differences in the risk of several cancers in the population of Nairobi, Kenya, using data from the Nairobi Cancer Registry. The registry records the variable "Tribe" for each case, a categorisation that includes, as well as 22 tribal groups, categories for Kenyans of European and of Asian origin, and non-Kenyan Africans. Tribes included in the final analysis were Kikuyu, Kamba, Kisii, Kalenjin, Luo, Luhya, Somalis, Asians, non-Kenyans, Caucasians, Other tribes and unknown. The largest group was taken as the reference category for the calculation of odds ratios; this was African Kenyans (for comparisons by race), and Kikuyus (the tribe with the largest numbers of cancer registrations (38% of the total)) for comparisons between the Kenyan tribes. P-values are obtained from the Wald test. Cancers that were more common among the white population than in black Kenyans were skin cancers and cancers of the bladder, while cancers that are more common in Kenyan Asians include colorectal, lung, breast, ovary, corpus uteri and non-Hodgkin lymphoma. Cancers that were less common among Asians and Caucasians were oesophagus, stomach and cervix cancer. Within the African population, there were marked differences in cancer risk by tribe. Among the tribes of Bantu ethnicity, the Kamba had higher risks of melanoma, Kaposi sarcoma, liver and cervix cancer, and lower risks of oesophagus, stomach, corpus uteri and nervous system cancers. Luo and Luhya had much higher odds of Kaposi sarcoma and Burkitt lymphoma.

Uganda experience-Using cost assessment of an established registry to project resources required to expand cancer registration

BACKGROUND

The objectives of this study are (1) to estimate the cost of operating the Kampala Cancer Registry (KCR) and (2) to use cost data from the KCR to project the resource needs and cost of expanding and sustaining cancer registration in Uganda, focusing on the recently established Gulu Cancer Registry (GCR) in rural Northern Uganda.

METHODS

We used Centers for Disease Control and Prevention's (CDC's) International Registry Costing Tool (IntRegCosting Tool) to estimate the KCR's activity-based cost for 2014. We grouped the registry activities into fixed cost, variable core cost, and variable other cost activities. After a comparison KCR and GCR characteristics, we used the cost of the KCR to project the likely ongoing costs for the new GCR.

RESULTS

The KCR incurred 42% of its expenditures in fixed cost activities, 40% for variable core cost activities, and the remaining 18% for variable other cost activities. The total cost per case registered was 28,201 Ugandan shillings (approximately US $10 in 2014) to collect and report cases using a combination of passive and active cancer data collection approaches. The GCR performs only active data collection, and covers a much larger area, but serves a smaller population compared to the KCR.

CONCLUSION

After identifying many differences between KCR and GCR that could potentially affect the cost of registration, our best estimate is that the GCR, though newer and in a rural area, should require fewer resources than the KCR to sustain operations as a stand-alone entity. The optimal structure of the GCR needs to be determined in the future.

Resource requirements for cancer registration in areas with limited resources: Analysis of cost data from four low- and middle-income countries

BACKGROUND

The key aims of this study were to identify sources of support for cancer registry activities, to quantify resource use and estimate costs to operate registries in low- and middle-income countries (LMIC) at different stages of development across three continents.

METHODS

Using the Centers for Disease Control and Prevention's (CDC's) International Registry Costing Tool (IntRegCosting Tool), cost and resource use data were collected from eight population-based cancer registries, including one in a low-income country (Uganda [Kampala)]), two in lower to middle-income countries (Kenya [Nairobi] and India [Mumbai]), and five in an upper to middle-income country (Colombia [Pasto, Barranquilla, Bucaramanga, Manizales and Cali cancer registries]).

RESULTS

Host institution contributions accounted for 30%-70% of total investment in cancer registry activities. Cancer registration involves substantial fixed cost and labor. Labor accounts for more than 50% of all expenditures across all registries. The cost per cancer case registered in low-income and lower-middle-income countries ranged from US $3.77 to US $15.62 (United States dollars). In Colombia, an upper to middle-income country, the cost per case registered ranged from US $41.28 to US $113.39. Registries serving large populations (over 15 million inhabitants) had a lower cost per inhabitant (less than US $0.01 in Mumbai, India) than registries serving small populations (under 500,000 inhabitants) [US $0.22] in Pasto, Colombia.

CONCLUSION

This study estimates the total cost and resources used for cancer registration across several countries in the limited-resource setting, and provides cancer registration stakeholders and registries with opportunities to identify cost savings and efficiency improvements. Our results suggest that cancer registration involve substantial fixed costs and labor, and that partnership with other institutions is critical for the operation and sustainability of cancer registries in limited resource settings. Although we included registries from a variety of limited-resource areas, information from eight registries in four countries may not be large enough to capture all the potential differences among the registries in limited-resource settings.

Population Attributable and Preventable Fractions: Cancer Risk Factor Surveillance, and Cancer Policy Projection

The proportions of new cancer cases and deaths that are caused by exposure to risk factors and that could be prevented are key statistics for public health policy and planning. This paper summarizes the methodologies for estimating, challenges in the analysis of, and utility of, population attributable and preventable fractions for cancers caused by major risk factors such as tobacco smoking, dietary factors, high body fat, physical inactivity, alcohol consumption, infectious agents, occupational exposure, air pollution, sun exposure, and insufficient breastfeeding. For population attributable and preventable fractions, evidence of a causal relationship between a risk factor and cancer, outcome (such as incidence and mortality), exposure distribution, relative risk, theoretical-minimum-risk, and counterfactual scenarios need to be clearly defined and congruent. Despite limitations of the methodology and the data used for estimations, the population attributable and preventable fractions are a useful tool for public health policy and planning.

Screening for liver cancer: results of a randomised controlled trial in Qidong, China

Objectives: To investigate the effectiveness of screening for liver cancer in reducing mortality from the disease in a high-risk population in China.

Setting: A randomised controlled trial was carried out among men aged 30-69 who were chronic carriers of hepatitis-B virus (HBsAg positive) during the period 1989-1995 in Qidong county, Jiangsu Province, China.

Methods: 5581 HBsAg carriers were identified by population screening and randomly assigned to a screening group (group A, 3712 men), and controls (group B, 1869 men). Screening was planned to be six monthly alpha-fetoprotein (AFP) assays, with follow-up of subjects having an abnormal (≥20 μg/l) test. All subjects were followed up for liver cancer and/or death until 31 December 1995.

Results: The overall sensitivity and specificity of the programme was 55.3% and 86.5%, respectively; in subjects who complied with all scheduled screening tests, the values were 80.0% and 80.9%. Three hundred and seventy-four primary liver cancer (PLC) cases were diagnosed. The percentage of cases in stage I was significantly higher in group A (29.6%) than in group B (6.0%). The one-, three-, and five-year relative survival rates were 23.7%, 7.0%, and 4.0% in group A, and 9.7%, 4.0%, and 4.1% in group B respectively, with no difference in five-year survival between the groups. The mortality rate in the screened group (1138 per 100,000 person-years) was not significantly different from that in the controls (1114 per 100,000). A Poisson regression model showed that the probability of death (rate ratio) in the screening group was 0.83 (95% CI 0.68-1.03) relative to the control group.

Conclusions: Screening with AFP resulted in earlier diagnosis of liver cancer, but the gain in lead time did not result in any overall reduction in mortality, because therapy for the patients found by screening was ineffective. Further studies using improved methods of screening, diagnosis and treatment are indicated.

Black-white differences in cancer risk in Harare, Zimbabwe, during 1991-2010

Data from 20 years of cancer registration in Harare (Zimbabwe) are used to investigate the risk of cancer in the white population of the city (of European origin), relative to that in blacks (of African origin). In the absence of information on the respective populations-at-risk, we calculated odds of each major cancer among all cancers, and took the odds ratios of whites to blacks. Some major differences reflect obvious phenotypic differences (the very high incidence of skin cancer-melanoma and nonmelanoma--in the white population), whereas others (high rates of liver cancer, Kaposi sarcoma and conjunctival cancers in blacks) are the result of differences in exposure to infectious agents. Of particular interest are cancers related to lifestyle factors, and how the differences in risk are changing over time, as a result of evolving lifestyles. Thus, the high risk of cancers of the esophagus and cervix uteri in blacks (relative to whites) and colorectal cancers in whites show little change over time. Conversely, the odds of breast cancer, on average four times higher in whites than blacks, has shown a significant decrease in the differential over time. Cancer of the prostate, with the odds initially (1991-1997) 15% higher in whites had become 33% higher in blacks by 2004-2010.

Cancer registries in Africa 2014: A survey of operational features and uses in cancer control planning

A questionnaire survey of all active population based cancer registries in sub-Saharan Africa obtained information on their characteristics (size, staffing, funding), methods of working, the nature of any links between registries and their respective Health Authorities (national and/or local), and the use of their data in research or cancer control planning. 23/25 registries (92%) responded. Sources of direct funding and estimated amounts from each source were established, and suggest that it is approximately US$8-9 per case registered. Almost half of the funding is used for routine data collection, processing and analysis. Staffing levels vary, partly as a function of the registry size (approximately one FTE per 300 cases registered). Most data collection is active, using multiple sources (median 10 per registry), and is largely paper-based (abstraction onto paper forms), although all use the computer system CanReg© for data entry, storage and analysis. Most reporting by the registries is remarkably timely, and in general, their results are widely used by health authorities and other stakeholders in planning and evaluating services, while research output is much more variable. These registries are the source of almost all the existing information on cancer incidence and mortality in sub-Saharan Africa, as published in IARC's "Globocan".

Tumor size and stage of breast cancer in Côte d'Ivoire and Republic of Congo - Results from population-based cancer registries

PURPOSE

Breast cancer is now the leading female cancer in sub-Saharan Africa, but there is relatively little information on breast cancer characteristics from this region. We studied, on a population basis, the size and stage of female breast cancer at diagnosis in Côte d'Ivoire and Republic of Congo.

METHODS

Data on tumor size and stage of breast cancer at diagnosis were collected by population-based cancer registries in Abidjan (the capital of Côte d'Ivoire; 141 cases) and Brazzaville (the capital of Republic of Congo; 139 cases) from a random group of female breast cancer cases that were diagnosed in 2008-2009 using the same protocol.

RESULTS

The majority of breast cancers in both countries were advanced cancers. In Côte d'Ivoire, 68% of tumors were ≥5 cm in diameter and 74% of cancers were stage III or IV at diagnosis; the corresponding proportions in Republic of Congo were 63% and 81%.

CONCLUSION

These results underscore the importance of increased awareness about early detection of breast cancer, as well as expansion of the capacity to provide appropriate diagnosis, treatment, and palliative care in sub-Saharan Africa.

Trends in cancer incidence in rural Eastern Cape Province; South Africa, 1998-2012

There are few cancer trend data reported in sub-Saharan Africa notably due to the scarcity of population-based cancer registries (PBCRs). The Eastern Cape Province PBCR is amongst the few registries in sub-Saharan Africa that reports data for a rural population. Trends in cancer incidence are reported for the period 1998-2012. Registered cases, age-standardized rates (ASRs) and standardized rate ratios are presented for the most common cancers in both males and females in three periods (1998-2002, 2003-2007 and 2008-2012). In males, the most commonly diagnosed cancer during the 15 year period was cancer of the oesophagus; incidence rates showed a significant decline over the 15 year period, entirely due to a 30% decrease between 2003-2007 and 2008-2012, to an ASR of 23.2 per 100,000 population. This was followed by prostate cancer, the incidence of which was more than doubled to a level of 9.9/100,000. In women, cancer of the cervix uteri has become the most common malignancy, with a significant increase in incidence during the period to 29.0/100,000. Oesophageal cancer is second in frequency, with (as in males) a significant decline in the final 10 years to an incidence of 14.5/100,000 in 2008-2012. The incidence of breast cancer increased by 61%, although the absolute rate remains low (12.2/100,000). The incidence rates of colorectal cancer are low, and the increases in incidence, although relatively large (35% in men, 63% in women) were not statistically significant. Kaposi sarcoma showed a dramatic increase in incidence in both sexes (3.5-fold in men, 11-fold in women) although the incidence remains relatively low by southern African standards. Cancer prevention and control activities in the area need to be informed by these data and strengthened.

Cancer in Africa 2012

BACKGROUND

Noncommunicable diseases, and especially cancers, are recognized as an increasing problem for low and middle income countries. Effective control programs require adequate information on the size, nature, and evolution of the health problem that they pose.

METHODS

We present estimates of the incidence and mortality of cancer in Africa in 2012, derived from "GLOBOCAN 2012," published by the International Agency for Research on Cancer.

RESULTS

There were 847,000 new cancer cases (6% of the world total) and 591,000 deaths (7.2% of the world total) in the 54 countries of Africa in 2012, with about three quarters in the 47 countries of Sub-Saharan Africa. While the cancer profiles often differ markedly between regions, the most common cancers in men were prostate (16.4% of new cancers), liver (10.7%), and Kaposi sarcoma (6.7%); in women, by far the most important are cancers of the breast (27.6% of all cancers) and cervix uteri (20.4%).

CONCLUSIONS

There are still deficiencies in surveillance systems, particularly in Sub-Saharan Africa and, specifically, of their most vital component, population-based cancer registries. With the number of annual cancer cases and deaths likely to increase by at least 70% by 2030, there is a pressing need for a coordinated approach to improving the extent and quality of services for cancer control in Africa, and better surveillance systems with which they can be planned and monitored.

IMPACT

The results are the best data currently available and provide a reasonable appraisal of the cancer situation in Africa.

Trends in the incidence of cancer in the black population of Harare, Zimbabwe 1991-2010

Incidence rates of different cancers have been calculated for the black population of Harare, Zimbabwe for a 20-year period (1991-2010) coinciding with continuing social and lifestyle changes, and the peak, and subsequent wane, of the HIV-AIDS epidemic. The overall risk of cancer increased during the period in both sexes, with rates of cervix and prostate cancers showing particularly dramatic increases (3.3% and 6.4% annually, respectively). By 2004, prostate cancer had become the most common cancer of men. The incidence of cancer of the esophagus, formerly the most common cancer of men, has remained relatively constant, whereas rates of breast and cervix cancers, the most common malignancies of women, have shown significant increases (4.9% and 3.3% annually, respectively). The incidence of Kaposi sarcoma increased to a maximum around 1998-2000 and then declined in all age groups, and in both sexes The incidence of squamous cell cancers of the conjunctiva is relatively high, with temporal trends similar to those of Kaposi sarcoma. Non-Hodgkin lymphoma, the fifth most common cancer of men and fourth of women, showed a steady increase in incidence throughout the period (6.7-6.9% annually), although rates in young adults (15-39) have decreased since 2001. Cancer control in Zimbabwe, as elsewhere in sub-Saharan Africa, involves meeting the challenge of emerging cancers associated with westernization of lifestyles (large bowel, breast and prostate), while the incidence of cancers associated with poverty and infection (liver, cervix and esophagus) shows little decline, and the residual burden of the AIDS-associated cancers remains significant.

Global burden of cancer in 2008: a systematic analysis of disability-adjusted life-years in 12 world regions

BACKGROUND

Country comparisons that consider the effect of fatal and non-fatal disease outcomes are needed for health-care planning. We calculated disability-adjusted life-years (DALYs) to estimate the global burden of cancer in 2008.

METHODS

We used population-based data, mostly from cancer registries, for incidence, mortality, life expectancy, disease duration, and age at onset and death, alongside proportions of patients who were treated and living with sequelae or regarded as cured, to calculate years of life lost (YLLs) and years lived with disability (YLDs). We used YLLs and YLDs to derive DALYs for 27 sites of cancers in 184 countries in 12 world regions. Estimates were grouped into four categories based on a country's human development index (HDI). We applied zero discounting and uniform age weighting, and age-standardised rates to enable cross-country and regional comparisons.

FINDINGS

Worldwide, an estimated 169·3 million years of healthy life were lost because of cancer in 2008. Colorectal, lung, breast, and prostate cancers were the main contributors to total DALYs in most world regions and caused 18-50% of the total cancer burden. We estimated an additional burden of 25% from infection-related cancers (liver, stomach, and cervical) in sub-Saharan Africa, and 27% in eastern Asia. We noted substantial global differences in the cancer profile of DALYs by country and region; however, YLLs were the most important component of DALYs in all countries and for all cancers, and contributed to more than 90% of the total burden. Nonetheless, low-resource settings had consistently higher YLLs (as a proportion of total DALYs) than did high-resource settings.

INTERPRETATION

Age-adjusted DALYs lost from cancer are substantial, irrespective of world region. The consistently larger proportions of YLLs in low HDI than in high HDI countries indicate substantial inequalities in prognosis after diagnosis, related to degree of human development. Therefore, radical improvement in cancer care is needed in low-resource countries.

FUNDING

Dutch Scientific Society, Erasmus University Rotterdam, and International Agency for research on Cancer.

Estimating and validating disability-adjusted life years at the global level: a methodological framework for cancer

BACKGROUND

Disability-adjusted life years (DALYs) link data on disease occurrence to health outcomes, and they are a useful aid in establishing country-specific agendas regarding cancer control. The variables required to compute DALYs are however multiple and not readily available in many countries. We propose a methodology that derives global DALYs and validate variables and DALYs based on data from various cancer registries.

METHODS

We estimated DALYs for four countries (Norway, Bulgaria, India and Uganda) within each category of the human development index (HDI). The following sources (indicators) were used: Globocan2008 (incidence and mortality), various cancer registries (proportion cured, proportion treated and duration of disease), treatment guidelines (duration of treatment), specific burden of disease studies (sequelae and disability weights), alongside expert opinion. We obtained country-specific population estimates and identified resource levels using the HDI, DALYs are computed as the sum of years of life lost and years lived with disabilities.

RESULTS

Using mortality:incidence ratios to estimate country-specific survival, and by applying the human development index we derived country-specific estimates of the proportion cured and the proportion treated. The fit between the estimates and observed data from the cancer registries was relatively good. The final DALY estimates were similar to those computed using observed values in Norway, and in WHO's earlier global burden of disease study. Marked cross-country differences in the patterns of DALYs by cancer sites were observed. In Norway and Bulgaria, breast, colorectal, prostate and lung cancer were the main contributors to DALYs, representing 54% and 45%, respectively, of the totals. These cancers contributed only 27% and 18%, respectively, of total DALYs in India and Uganda.

CONCLUSIONS

Our approach resulted in a series of variables that can be used to estimate country-specific DALYs, enabling global estimates of DALYs and international comparisons that support priorities in cancer control.

Evaluation of the nationwide cervical screening programme in Thailand: a case-control study

OBJECTIVES

To evaluate the effectiveness of the Pap smear screening programme in Thailand in the prevention of invasive cervical cancer.

SETTING

Four tertiary hospitals, in two provinces of north-east Thailand.

METHODS

A hospital-based case-control study of women aged 30-64, who were resident in north-east Thailand. A total of 130 women with a diagnosis of invasive cervical cancer were compared with two groups of controls: a) hospital controls, b) hospital patient companions. Information on risk factors for cervical cancer and history of screening by cytology (Pap smear) were collected using a structured interview.

RESULTS

Eighty percent of control subjects reported having had a Pap test in the past, and some two-thirds within the three years before interview. There was a significant protective effect for multiple (6+) previous screening tests as reported by 20% of controls. When women who had tests less than six months prior to the study were excluded, there was a strong, significant protective effect of the number of tests (for 1-5 tests: OR = 0.45 95% CI = 0.25 to 0.84, and for 6+ tests: OR = 0.29 95% CI = 0.11 to 0.82). Tests carried out 1-2 years and 3+ years before diagnosis were associated with an OR of 0.27 (95% CI = 0.13-0.56) and 0.42 (95% CI = 0.20-0.88), respectively.

CONCLUSIONS

The cervical screening programme in north-east Thailand has achieved excellent coverage and is preventing cervical cancer. Women who have been screened multiple times are at substantially lower risk than those only screened a few times suggesting that the quality of the screening could be improved.

1. The fraction of cancer attributable to lifestyle and environmental factors in the UK in 2010

The overall objective of the study is to estimate the percentage of cancers (excluding non-melanoma skin cancer) in the UK in 2010 that were the result of exposure to 14 major lifestyle, dietary and environmental risk factors: tobacco, alcohol, four elements of diet (consumption of meat, fruit and vegetables, fibre and salt), overweight, lack of physical exercise, occupation, infections, radiation (ionising and solar), use of hormones and reproductive history (breast feeding). The number of new cases attributable to suboptimal exposure levels in the past, relative to a theoretical optimum exposure distribution, is evaluated. For most of the exposures, the attributable fraction was calculated based on the distribution of exposure prevalence (around 2000), the difference from the theoretical optimum (by age group and sex) and the relative risk per unit difference. For tobacco smoking, the method developed by Peto et al (1992) was used, which relies on the ratio between observed incidence of lung cancer in smokers and that in non-smokers, to calibrate the risk. This article outlines the structure of the supplement – a section for each of the 14 exposures, followed by a Summary chapter, which considers the relative contributions of each factor to the total number of cancers diagnosed in the UK in 2010 that were, in theory, avoidable.

Cancer burden in Africa and opportunities for prevention

Cancer is an emerging public health problem in Africa. About 715,000 new cancer cases and 542,000 cancer deaths occurred in 2008 on the continent, with these numbers expected to double in the next 20 years simply because of the aging and growth of the population. Furthermore, cancers such as lung, female breast, and prostate cancers are diagnosed at much higher frequencies than in the past because of changes in lifestyle factors and detection practices associated with urbanization and economic development. Breast cancer in women and prostate cancer in men have now become the most commonly diagnosed cancers in many Sub-Saharan African countries, replacing cervical and liver cancers. In most African countries, cancer control programs and the provision of early detection and treatment services are limited despite this increasing burden. This paper reviews the current patterns of cancer in Africa and the opportunities for reducing the burden through the application of resource level interventions, including implementation of vaccinations for liver and cervical cancers, tobacco control policies for smoking-related cancers, and low-tech early detection methods for cervical cancer, as well as pain relief at the palliative stage of cancer.

16. The fraction of cancer attributable to lifestyle and environmental factors in the UK in 2010

This chapter summarises the results of the preceding sections, which estimate the fraction of cancers occurring in the UK in 2010 that can be attributed to sub-optimal, past exposures of 14 lifestyle and environmental risk factors. For each of 18 cancer types, we present the percentage of cases attributable to one or all of the risk factors considered (tobacco, alcohol, four elements of diet (consumption of meat, fruit and vegetables, fibre, and salt), overweight, lack of physical exercise, occupation, infections, radiation (ionising and solar), use of hormones, and reproductive history (breast feeding)).Exposure to less than optimum levels of the 14 factors was responsible for 42.7% of cancers in the UK in 2010 (45.3% in men, 40.1% in women)--a total of about 134,000 cases.Tobacco smoking is by far the most important risk factor for cancer in the UK, responsible for 60, 000 cases (19.4% of all new cancer cases) in 2010. The relative importance of other exposures differs by sex. In men, deficient intake of fruits and vegetables (6.1%), occupational exposures (4.9%) and alcohol consumption (4.6%) are next in importance, while in women, it is overweight and obesity (because of the effect on breast cancer)--responsible for 6.9% of cancers, followed by infectious agents (3.7%).Population-attributable fractions provide a valuable quantitative appraisal of the impact of different factors in cancer causation, and are thus helpful in prioritising cancer control strategies. However, quantifying the likely impact of preventive interventions requires rather complex scenario modelling, including specification of realistically achievable population distributions of risk factors, and the timescale of change, as well as the latent periods between exposure and outcome, and the rate of change following modification in exposure level.

Cancer incidence in the United Kingdom: projections to the year 2030

Background:

Projections of cancer incidence are important for planning health services and to provide a baseline for assessing the impact of public health interventions.

Methods:

Rates estimated from smooth function age–period–cohort modelling of cancer incidence data from Great Britain 1975 to 2007 are extrapolated to 2030 and applied to UK population projections. Prostate and breast cancer projections take into account the effect of screening.

Results:

Overall rates of cancer are projected to be stable over the next 20 years, but this masks individual changes. In both sexes, age-standardised rates of cancers of the stomach, larynx, bladder and leukaemia are projected to fall by ⩾1% per year, whereas cancers of the lip, mouth and pharynx (ICD-10 C00-C14) and melanoma are projected to increase by ⩾1% per year. The growing and aging populations will have a substantial impact: numbers of cancers in men and women are projected to increase by 55% (from 149 169 to 231 026) and 35% (from 148 716 to 200 929), respectively, between 2007 and 2030. The model used yields similar results to those of Nordpred, but is more flexible.

Conclusion:

Without new initiatives for smoking and obesity reduction, the number of cancers in the United Kingdom will increase substantially reflecting the growing and aging populations.