Trends in the incidence of colorectal cancer in sub-Saharan Africa: A population-based registry study.

In sub-Saharan Africa, colorectal cancer (CRC) has historically been considered a rare disease, although some previous studies have suggested that the incidence is increasing. We examine time trends in the incidence of CRC using data from 12 population-based cancer registries in 11 countries of sub-Saharan Africa that were able to provide time series data for periods of 12 or more years, or with earlier data with which recent rates may be compared. Age-standardized incidence rates were highest in the higher-income countries, and were increasing in all of the populations studied, and these increases were statistically significant in all but three. Current evidence has suggested a link between the increased adoption of western lifestyle habits with colorectal cancer, and along with increasing urbanization of African populations, there is an increase in body weight, as well as evidence of increasing consumption of meat, sugars, and alcohol.

Ovarian cancer survival in sub-Saharan Africa by human development index and histological subtypes: A population-based registry study.

Ovarian cancer (OC) is the fourth most common cancer of women in sub-Saharan Africa (SSA), although few data have been published on population-level survival. We estimate ovarian cancer survival in SSA by human development index and histological subtype, using data from seven population-based cancer registries in six countries: Kenya (Nairobi and Eldoret), Mauritius, Uganda (Kampala), Cote d'Ivoire (Abidjan), Ethiopia (Addis Ababa) and South Africa (Eastern Cape). A total of 644 cases diagnosed during 2008-2014 were included, with 77% being of epithelial subtypes (range 47% [Abidjan]-80% [Mauritius]). The overall observed survival in the study cohort was 73.4% (95% CI: 69.8, 77.0) at 1 year, 54.4% (95% CI: 50.4, 58.7) at 3 years and 45.0% (95% CI: 41.0, 49.4) at 5 years. Relative survival at Year 1 ranged from 44.4% in Kampala to 86.3% in Mauritius, with a mean for the seven series of 67.4%. Relative survival was highest in Mauritius at 72.2% and lowest in Kampala, Uganda at 19.5%, with a mean of 47.8%. There was no difference in survival by age at diagnosis. Patients from high and medium HDI countries had significantly better survival than those from low HDI countries. Women with cancers of epithelial cell origin had much lower survival compared to women with other histological subtypes (p = .02). Adjusted for the young age of the African patients with ovarian cancer (44% aged <50) survival is much lower than in USA or Europe, and underlines the need for improvements in the access to diagnosis and treatment of OC in SSA.

Global variations in lung cancer incidence by histological subtype in 2020: a population-based study.

BACKGROUND: Lung cancer is the second most common cancer worldwide, yet the distribution by histological subtype remains unknown. We aimed to quantify the global, regional, and national burden of lung cancer incidence for the four main subtypes in 185 countries and territories. METHODS: In this population-based study, we used data from Cancer Incidence in Five Continents Volume XI and the African Cancer Registry Network to assess the proportions of adenocarcinoma, squamous cell carcinoma, small-cell carcinoma, and large-cell carcinoma among all lung cancers by country, sex, and age group and subsequently applied these data to corresponding national (GLOBOCAN) estimates of lung cancer incidence in 2020. Unspecified morphologies were reallocated to specified subtypes. Age-standardised incidence rates were calculated using the world standard population to compare subtype risks worldwide, adjusted for differences in age composition between populations by country. FINDINGS: In 2020, there were an estimated 2 206 771 new cases of lung cancer, with 1 435 943 in males and 770 828 in females worldwide. In males, 560 108 (39%) of all lung cancer cases were adenocarcinoma, 351 807 (25%) were squamous cell carcinoma, 163 862 (11%) were small-cell carcinoma, and 115 322 (8%) were large-cell carcinoma cases. In females, 440 510 (57%) of all lung cancer cases were adenocarcinoma, 91 070 (12%) were squamous cell carcinoma, 68 224 (9%) were small-cell carcinoma, and 49 246 (6%) were large-cell carcinoma cases. Age-standardised incidence rates for adenocarcinoma, squamous cell carcinoma, small-cell carcinoma, and large-cell carcinoma, respectively, were estimated to be 12·4, 7·7, 3·6, and 2·6 per 100 000 person-years in males and 8·3, 1·6, 1·3, and 0·9 per 100 000 person-years in females worldwide. The incidence rates of adenocarcinoma exceeded those of squamous cell carcinoma in 150 of 185 countries in males and in all 185 countries in females. The highest age-standardised incidence rates per 100 000 person-years for adenocarcinoma, squamous cell carcinoma, small-cell carcinoma, and large-cell carcinoma, respectively, for males occurred in eastern Asia (23·5), central and eastern Europe (17·5), western Asia (7·2), and south-eastern Asia (11·0); and for females occurred in eastern Asia (16·0), northern America (5·4), northern America (4·7), and south-eastern Asia (3·4). The incidence of each subtype showed a clear gradient according to the Human Development Index for male and female individuals, with increased rates in high and very high Human Development Index countries. INTERPRETATION: Adenocarcinoma has become the most common subtype of lung cancer globally in 2020, with incidence rates in males exceeding those of squamous cell carcinoma in most countries, and in females in all countries. Our findings provide new insights into the nature of the global lung cancer burden and facilitates tailored national preventive actions within each world region. FUNDING: None.

Regional Variation in the Tumor Microenvironment, Immune Escape and Prognostic Factors in Breast Cancer in Sub-Saharan Africa.

The low overall survival rates of patients with breast cancer in sub-Saharan Africa (SSA) are driven by regionally differing tumor biology, advanced tumor stages at diagnosis, and limited access to therapy. However, it is not known whether regional differences in the composition of the tumor microenvironment (TME) exist and affect patients' prognosis. In this international, multicentre cohort study, 1,237 formalin-fixed, paraffin-embedded breast cancer samples, including samples of the "African Breast Cancer-Disparities in Outcomes (ABC-DO) Study," were analyzed. The immune cell phenotypes, their spatial distribution in the TME, and immune escape mechanisms of breast cancer samples from SSA and Germany (n = 117) were investigated using histomorphology, conventional and multiplex IHC, and RNA expression analysis. The data revealed no regional differences in the number of tumor-infiltrating lymphocytes (TIL) in the 1,237 SSA breast cancer samples, while the distribution of TILs in different breast cancer IHC subtypes showed regional diversity, particularly when compared with German samples. Higher TIL densities were associated with better survival in the SSA cohort (n = 400), but regional differences concerning the predictive value of TILs existed. High numbers of CD163+ macrophages and CD3+CD8+ T cells accompanied by reduced cytotoxicity, altered IL10 and IFNγ levels and downregulation of MHC class I components were predominantly detected in breast cancer samples from Western SSA. Features of nonimmunogenic breast cancer phenotypes were associated with reduced patient survival (n = 131). We therefore conclude that regional diversity in the distribution of breast cancer subtypes, TME composition, and immune escape mechanisms should be considered for therapy decisions in SSA and the design of personalized therapies. See related Spotlight by Bergin et al., p. 705.

Trends in the incidence of ovarian cancer in sub-Saharan Africa.

Ovarian cancer (OC) is one of the commonest cancers of women in sub-Saharan Africa (SSA), although to date no data have been available on time trends in incidence to better understand the disease pattern in the region. We estimate time trends by histological subtype from 12 population-based cancer registries in 11 countries: Kenya (Nairobi), Mauritius, Seychelles, Uganda (Kampala), Congo (Brazzaville), Zimbabwe (Bulawayo and Harare), Cote d'Ivoire (Abidjan), The Gambia, Mali (Bamako), Nigeria (Ibadan) and South Africa (Eastern Cape). The selected registries were those that could provide consistent estimates of the incidence of ovarian cancer and with quality assessment for periods of 10 or more years. A total of 5423 cases of OC were included. Incidence rates have been increasing in all registries except Brazzaville, Congo, where a nonsignificant decline of 1% per year was seen. Statistically significant average annual increases were seen in Mauritius (2.5%), Bamako (5.3%), Ibadan (3.9%) and Eastern Cape (8%). Epithelial ovarian cancer was responsible for the increases observed in all registries. Statistically significant average annual percentage changes (AAPC) for epithelial OC were present in Bamako (AAPC = 5.9%), Ibadan (AAPC = 4.7%) and Eastern Cape (AAPC = 11.0%). Creating awareness among professionals of the growing importance of the disease is surely an important step to improving availability of, and access to, diagnosis and treatment of OC in SSA. Support must be given to the cancer registries to improve the availability of good-quality data on this important cancer.

Prostate cancer survival in sub-Saharan Africa by age, stage at diagnosis, and human development index: a population-based registry study.

OBJECTIVES: To estimate observed and relative survival of prostate cancer patients in sub-Saharan Africa (SSA) and to examine the influence of age, stage at diagnosis and the Human Development Index (HDI). PATIENTS AND METHODS: In this comparative registry study, we selected a random sample of 1752 incident cases of malign prostatic neoplasm from 12 population-based cancer registries from 10 SSA countries, registered between 2005 and 2015. We analyzed the data using Kaplan-Meier and Ederer II methods to obtain outcome estimates and flexible Poisson regression modeling to calculate the excess hazards of death RESULTS: For the 1406 patients included in the survival analyses, 763 deaths occurred during 3614 person-years of observation. Of patients with known stage, 45.2% had stage IV disease, 31.2% stage III and only 23.6% stage I and II. The 1 and 5-year relative survival for the entire cohort was 78.0% (75.4-80.7) and 60.0% (55.7-64.6), while varying between the registries. Late presentation was associated with increased excess hazards and a 0.1 increase in the HDI was associated with a 20% lower excess hazard of death, while for age at diagnosis no association was found. CONCLUSIONS: We found poor survival of SSA prostatic tumor patients, as well as high proportions of late stage presentation, which are associated with inferior outcome. This calls for investment in health-care systems and action regarding projects to raise awareness among the population to achieve earlier diagnosis and improve survival.

Colorectal cancer survival in sub-Saharan Africa by age, stage at diagnosis and Human Development Index: A population-based registry study.

There are limited population-based survival data for colorectal cancer (CRC) in sub-Saharan Africa. Here, 1707 persons diagnosed with CRC from 2005 to 2015 were randomly selected from 13 population-based cancer registries operating in 11 countries in sub-Saharan Africa. Vital status was ascertained from medical charts or through next of kin. 1-, 3- and 5-year overall and relative survival rates for all registries and for each registry were calculated using the Kaplan-Meier estimator. Multivariable analysis was used to examine the associations of 5-year relative survival with age at diagnosis, stage and country-level Human Development Index (HDI). Observed survival for 1448 patients with CRC across all registries combined was 72.0% (95% CI 69.5-74.4%) at 1 year, 50.4% (95% CI 47.6-53.2%) at 3 years and 43.5% (95% CI 40.6-46.3%) at 5 years. We estimate that relative survival at 5 years in these registry populations is 48.2%. Factors associated with poorer survival included living in a country with lower HDI, late stage at diagnosis and younger or older age at diagnosis (<50 or ≥70 years). For example, the risk of death was 1.6 (95% CI 1.2-2.1) times higher for patients residing in medium-HDI and 2.7 (95% CI 2.2-3.4) times higher for patients residing in low-HDI compared to those residing in high-HDI countries. Survival for CRC remains low in sub-Saharan African countries, though estimates vary considerably by HDI. Strengthening health systems to ensure access to prevention, early diagnosis and appropriate treatment is critical in improving outcomes of CRC in the region.

Rising Prostate Cancer Incidence in Sub-Saharan Africa: A Trend Analysis of Data from the African Cancer Registry Network.

BACKGROUND: Prostate cancer is the leading cancer in men in sub-Saharan Africa (SSA) regarding incidence and mortality. Published data from a few registries in SSA suggest that the rates are still rising, but there is little comprehensive information on the time trends of prostate cancer incidence. METHODS: We analyzed registry data on 13,170 incident prostate cancer cases in men aged 40 years or above, from 12 population-based cancer registries in 11 SSA countries, with at least a 10-year time span of comparable data. RESULTS: We observed an increase in cumulative risks (CR) and age-standardized incidence rates (ASR) over time in all registries (statistically significant in all but one). The highest values of CR were found in Seychelles and Harare (Zimbabwe). The highest annual increase in the ASRs was seen in Seychelles and Eastern Cape (South Africa), whereas the lowest was seen in Mauritius. We mainly found a steady increase in incidence with age and during successive periods. CONCLUSIONS: This analysis reveals that prostate cancer incidence rates are rising in many populations in SSA-often very rapidly-which is in contrast to recent observations worldwide. We acknowledge that the reasons are multifactorial and largely remain unclear, but believe that they are primarily associated with improvements in health care systems, for example, a broader use of prostate-specific antigen testing. IMPACT: This study is the first to compare population-level data on time trends of prostate cancer incidence between multiple countries of SSA, presenting the different rates of increase in 11 of them.

Cervical cancer survival in sub-Saharan Africa by age, stage at diagnosis and Human Development Index: A population-based registry study.

Cervical cancer is the leading cause of cancer death in African women. We sought to estimate population-based survival and evaluate excess hazards for mortality in African women with cervical cancer, examining the effects of country-level Human Development Index (HDI), age and stage at diagnosis. We selected a random sample of 2760 incident cervical cancer cases, diagnosed in 2005 to 2015 from 13 population-based cancer registries in 11 countries (Benin, Cote d'Ivoire, Ethiopia, Kenya, Mauritius, Mozambique, Namibia, Seychelles, South Africa, Uganda and Zimbabwe) through the African Cancer Registry Network. Of these, 2735 were included for survival analyses. The 1-, 3- and 5-year observed and relative survival were estimated by registry, stage and country-level HDI. We used flexible Poisson regression models to estimate the excess hazards for death adjusting for age, stage and HDI. Among patients with known stage, 65.8% were diagnosed with Stage III-IV disease. The 5-year relative survival for Stage I-II cervical cancer in high HDI registry areas was 67.5% (42.1-83.6) while it was much lower (42.2% [30.6-53.2]) for low HDI registry areas. Independent predictors of mortality were Stage III-IV disease, medium to low country-level HDI and age >65 years at cervical cancer diagnosis. The average relative survival from cervix cancer in the 11 countries was 69.8%, 44.5% and 33.1% at 1, 3 and 5 years, respectively. Factors contributing to the HDI (such as education and a country's financial resources) are critical for cervical cancer control in SSA and there is need to strengthen health systems with timely and appropriate prevention and treatment programmes.

Trends in cervical cancer incidence in sub-Saharan Africa.

BACKGROUND: Cervical cancer is the second most common cancer and the leading cause of cancer death in women in sub-Saharan Africa (SSA). METHODS: Trends in the incidence of cervical cancer are examined for a period of 10-25 years in 10 population-based cancer registries across eight SSA countries (Gambia, Kenya, Malawi, Mauritius, Seychelles, South Africa, Uganda and Zimbabwe). A total of 21,990 cases of cervical cancer were included in the analyses. RESULTS: Incidence rates had increased in all registries for some or all of the periods studied, except for Mauritius with a constant annual 2.5% decline. Eastern Cape and Blantyre (Malawi) registries showed significant increases over time, with the most rapid being in Blantyre (7.9% annually). In Kampala (Uganda), a significant increase was noted (2.2%) until 2006, followed by a non-significant decline. In Eldoret, a decrease (1998-2002) was followed by a significant increase (9.5%) from 2002 to 2016. CONCLUSION: Overall, cervical cancer incidence has been increasing in SSA. The current high-level advocacy to reduce the burden of cervical cancer in SSA needs to be translated into support for prevention (vaccination against human papillomavirus and population-wide screening), with careful monitoring of results through population-based registries.

The evolving epidemic of breast cancer in sub-Saharan Africa: Results from the African Cancer Registry Network.

Breast cancer (BC) is the leading cause of cancer in sub-Saharan Africa (SSA) with rapidly increasing incidence rates reported in Uganda and Zimbabwe. However, the magnitude of these rising trends in premenopausal and postmenopausal women is unknown in most African countries. We used data from the African Cancer Registry Network on incident breast cancers in women from 11 population-based cancer registries in 10 countries representing each of the four SSA regions. We explored incidence changes among women before and after age 50 by calendar period and, where possible, generational effects in this unique sub-Saharan African cohort. Temporal trends revealed increasing incidence rates in all registries during the study period, except in Nairobi where rates stabilised during 2010 to 2014 after rapidly increasing from 2003 to 2010 (APC = 8.5 95%, CI: 3.0-14.2). The cumulative risk varied between and within regions, with the highest risks observed in Nairobi-Kenya, Mauritius and the Seychelles. There were similar or more rapidly increasing incidence rates in women aged 50+ compared to women <50 years in all registries except The Gambia. Birth cohort analyses revealed increases in the incidence rates in successive generations of women aged 45 and over in Harare-Zimbabwe and Kampala-Uganda. In conclusion, the incidence of BC is increasing rapidly in many parts of Africa; however, the magnitude of these changes differs. These results highlight the need for urgent actions across the cancer continuum from in-depth risk factor studies to provision of adequate therapy as well as the necessity of supporting the maintenance of good quality population-based cancer registration in Africa.

Breast cancer survival in sub-Saharan Africa by age, stage at diagnosis and human development index: A population-based registry study.

Breast cancer is the leading cancer diagnosis and second most common cause of cancer deaths in sub-Saharan Africa (SSA). Yet, there are few population-level survival data from Africa and none on the survival differences by stage at diagnosis. Here, we estimate breast cancer survival within SSA by area, stage and country-level human development index (HDI). We obtained data on a random sample of 2,588 breast cancer incident cases, diagnosed in 2008-2015 from 14 population-based cancer registries in 12 countries (Benin, Cote d'Ivoire, Ethiopia, Kenya, Mali, Mauritius, Mozambique, Namibia, Seychelles, South Africa, Uganda and Zimbabwe) through the African Cancer Registry Network. Of these, 2,311 were included for survival analyses. The 1-, 3- and 5-year observed and relative survival (RS) were estimated by registry, stage and country-level HDI. We equally estimated the excess hazards adjusting for potential confounders. Among patients with known stage, 64.9% were diagnosed in late stages, with 18.4% being metastatic at diagnosis. The RS varied by registry, ranging from 21.6%(8.2-39.8) at Year 3 in Bulawayo to 84.5% (70.6-93.5) in Namibia. Patients diagnosed at early stages had a 3-year RS of 78% (71.6-83.3) in contrast to 40.3% (34.9-45.7) at advanced stages (III and IV). The overall RS at Year 1 was 86.1% (84.4-87.6), 65.8% (63.5-68.1) at Year 3 and 59.0% (56.3-61.6) at Year 5. Age at diagnosis was not independently associated with increased mortality risk after adjusting for the effect of stage and country-level HDI. In conclusion, downstaging breast cancer at diagnosis and improving access to quality care could be pivotal in improving breast cancer survival outcomes in Africa.

Trends in cancer incidence in the Republic of Mauritius, 1991-2015.

INTRODUCTION: Mauritius, a small state, is among the few African countries where cancer registration is population based and nationwide. We reported trends in cancer incidence for twenty five years as well as the mortality to incidence ratio (MIR) as main quality indicator of the Mauritius National Cancer Registry (MNCR). MATERIALS AND METHODS: We calculated age standardised incidence rates (ASRs) of cancers by sex and by 5 year age group for five successive year periods from 1991 to 2015. The average annual percentage change (AAPC) were determined by sex and cancer sites. MIRs were compared for the period 2001-2004 and 2012-2015. RESULTS: In males, the most common cancer sites (in terms of ASRs per 100,000) were those of the colon-rectum (17.0), prostate (16.5), trachea-bronchus-lung (13.0), stomach (8.4) and lip-oral cavity-pharynx (7.7). The AAPC were +3.9%, +4.2%, +0.5%, -0.1% and -1.3% respectively. In females, the most frequent sites were breast (53.7), colon-rectum (13.2), cervix uteri (11.2), corpus uteri (7.7) and ovary (5.7). The AAPC were +3.4%, +4.4%, -2%, +5.2% and -0.1% respectively. The most significant decrease in MIRs among males were liver (1.9 to 1.0), stomach (1.3 to 0.8) and lung (1.7 to 1.2) cancers while among females, they were pancreas (3.4 to 1.3), liver (1.8 to 1.2) and stomach (1.5 to 0.8) cancers. CONCLUSION: The most common cancers were those associated with 'westernisation' of lifestyle. Our figures contrast with other Sub-Saharan Africa countries where infection related cancers are most predominant. The MNCR has also improved its data quality over time.

Epidemiology of rotavirus diarrhea and diversity of rotavirus strains among children less than 5 years of age with acute gastroenteritis in Mauritius: June 2008 to December 2010.

BACKGROUND: Rotavirus is an important etiologic agent of diarrhea worldwide and ongoing surveillance is essential to monitor strain diversity. To describe the epidemiology of rotavirus disease and circulating rotavirus strains in Mauritius, surveillance for rotavirus diarrhea was conducted at 2 regional hospitals from June 2008 through December 2010. METHODS: A total of 787 fecal samples from children <5 years of age admitted to the pediatric ward with acute gastroenteritis was collected within 48 hours of hospitalization and analyzed for group A rotavirus. A subset of rotavirus-positive samples was subjected to polyacrylamide gel electrophoresis and VP4 and VP7 genotyping. RESULTS: Rotavirus was detected in 327 (41.6%) stools. Highest prevalence of rotavirus infection occurred in children <2 years of age, predominately between 12 and 23 months. Three seasonal peaks were observed during the study period: July to October 2008, October to December 2009 and July to October 2010. Polyacrylamide gel electrophoresis analysis of 116 positive samples yielded only long electropherotypes. The predominant circulating strain was G3P[8] (89%) from June through December 2008, G4P[8] (76%) from January through December 2009 and G1P[8] (90%) from January through December 2010. CONCLUSIONS: The diversity of rotavirus strains detected in this study highlights the need for continuous surveillance and data generated can be used to advocate for rotavirus vaccine introduction.

Reemergence of dengue in Mauritius.

Dengue reemerged in Mauritius in 2009 after an absence of >30 years, and >200 cases were confirmed serologically. Molecular studies showed that the outbreak was caused by dengue virus type 2. Phylogenetic analysis of the envelope gene identified 2 clades of the virus. No case of hemorrhagic fever was recorded.

Detection of human papillomavirus from archival tissues in cervical cancer patients in Mauritius.

BACKGROUND: Around half a million new cases of cervical cancer are diagnosed worldwide each year, accounting for almost 300,000 deaths. Development of cervical cancer can be multi-factorial, but high-risk human papillomaviruses (HPV) have been associated with the aetiology of cervical cancer. It is believed that HPV DNA integrates into the host DNA causing abnormal cell growth with cells becoming carcinogenic and spreading metastatically. In Mauritius, cervical cancer account for 65% of gynaecological cancers and 3.4% of the cervical cancers are diagnosed at the stage of carcinoma in situ. OBJECTIVES: To determine the prevalence of HPV in histological samples from patients with cervical cancer in Mauritius. STUDY DESIGN: DNA from archival cervical samples from a cohort of 65 patients suffering from cervical cancer and controls from Mauritius were tested for the presence of HPV using MY09/11 and GP5+/6+ primer sets. RESULTS: In a cohort of 65 patients from Mauritius, diagnosed with cervical cancer in the year 2000, 19% of cervical histology sections were found to be positive for the presence of high-grade HPV, exclusively HPV18 using MY09 and MY11 primers. Only 15% of the Mauritian population is over 50 years of age, whereas 66% (35) of the diagnosed cases of cervical cancer were seen in patients above 50 years with 50% (5) affected with HPV. These findings suggest that for an infection with HPV to develop into cancer may take years if not decades. Differences were noted using two different primer sets, MY09/11 and GP5+/6+. The latter produce a much smaller amplicon (150bp) compared to the former ( approximately 450bp). Seven additional positive cases were detected with the GP5+/6+ primer set, resulting in an apparent prevalence of 32% as compared to the 19% seen with the MY09/11 primer set. This may indicate that some degradation of the target DNA has occurred during processing and storage of histological samples. CONCLUSION: Using primer sets MY09/11 and GP5+/6+, only HPV type 18 was found in the Mauritian cohort with a prevalence of 32%.