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1.
Int J Cancer ; 152(11): 2269-2282, 2023 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-36733225

RESUMEN

Tobacco use is a well-established risk factor for oesophageal squamous cell carcinoma (ESCC) but the extent of its contribution to the disease burden in the African oesophageal cancer corridor has not been comprehensively elucidated, including by type of tobacco use. We investigated the contribution of tobacco use (smoking and smokeless) to ESCC in Tanzania, Malawi and Kenya. Hospital-based ESCC case-control studies were conducted in the three countries. Incident cases and controls were interviewed using a comprehensive questionnaire which included questions on tobacco smoking and smokeless tobacco use. Logistic regression models were used to estimate odds ratios (OR) and their 95% confidence intervals (CI) of ESCC associated with tobacco, adjusted for age, sex, alcohol use, religion, education and area of residence. One thousand two hundred seventy-nine cases and 1345 controls were recruited between August 5, 2013, and May 24, 2020. Ever-tobacco use was associated with increased ESCC risk in all countries: Tanzania (OR 3.09, 95%CI 1.83-5.23), and in Malawi (OR 2.45, 95%CI 1.80-3.33) and lesser in Kenya (OR 1.37, 95%CI 0.94-2.00). Exclusive smokeless tobacco use was positively associated with ESCC risk, in Tanzania, Malawi and Kenya combined (OR 1.92, 95%CI 1.26-2.92). ESCC risk increased with tobacco smoking intensity and duration of smoking. Tobacco use is an important risk factor of ESCC in Tanzania, Malawi and Kenya. Our study provides evidence that smoking and smokeless tobacco cessation are imperative in reducing ESCC risk.


Asunto(s)
Carcinoma de Células Escamosas , Neoplasias Esofágicas , Carcinoma de Células Escamosas de Esófago , Tabaco sin Humo , Humanos , Carcinoma de Células Escamosas de Esófago/epidemiología , Carcinoma de Células Escamosas de Esófago/etiología , Tabaco sin Humo/efectos adversos , Carcinoma de Células Escamosas/epidemiología , Carcinoma de Células Escamosas/etiología , Fumar , Neoplasias Esofágicas/etiología , Neoplasias Esofágicas/complicaciones , Factores de Riesgo , Fumar Tabaco , Estudios de Casos y Controles
2.
Br J Cancer ; 127(6): 1106-1115, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35768549

RESUMEN

BACKGROUND: Consumption of very-hot beverages/food is a probable carcinogen. In East Africa, we investigated esophageal squamous cell carcinoma (ESCC) risk in relation to four thermal exposure metrics separately and in a combined score. METHODS: From the ESCCAPE case-control studies in Blantyre, Malawi (2017-20) and Kilimanjaro, Tanzania (2015-19), we used logistic regression models adjusted for country, age, sex, alcohol and tobacco, to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for self-reported thermal exposures whilst consuming tea, coffee and/or porridge. RESULTS: The study included 849 cases and 906 controls. All metrics were positively associated with ESCC: temperature of drink/food (OR 1.92 (95% CI: 1.50, 2.46) for 'very hot' vs 'hot'), waiting time before drinking/eating (1.76 (1.37, 2.26) for <2 vs 2-5 minutes), consumption speed (2.23 (1.78, 2.79) for 'normal' vs 'slow') and mouth burning (1.90 (1.19, 3.01) for ≥6 burns per month vs none). Amongst consumers, the composite score ranged from 1 to 12, and ESCC risk increased with higher scores, reaching an OR of 4.6 (2.1, 10.0) for scores of ≥9 vs 3. CONCLUSIONS: Thermal exposure metrics were strongly associated with ESCC risk. Avoidance of very-hot food/beverage consumption may contribute to the prevention of ESCC in East Africa.


Asunto(s)
Neoplasias Esofágicas , Carcinoma de Células Escamosas de Esófago , Bebidas/efectos adversos , Estudios de Casos y Controles , Neoplasias Esofágicas/epidemiología , Neoplasias Esofágicas/etiología , Carcinoma de Células Escamosas de Esófago/epidemiología , Calor , Humanos , Modelos Logísticos , Malaui/epidemiología , Factores de Riesgo , Tanzanía/epidemiología
3.
Int J Cancer ; 149(6): 1274-1283, 2021 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-34004024

RESUMEN

Geophagia, the intentional practice of consuming soil, occurs across the African esophageal cancer corridor, particularly during pregnancy. We investigated whether this practice is linked to endemic esophageal squamous cell carcinoma (ESCC) in this region. We conducted ESCC case-control studies in Tanzania, Malawi and Kenya. Cases were patients with incident histologically/clinically confirmed ESCC and controls were hospital patients/visitors without digestive diseases. Participants were asked if they had ever eaten soil (never/regularly/pregnancy-only). Odds ratios (OR) are adjusted for sex, age, tobacco, alcohol, country, religion and marital status. Overall, 934 cases (Malawi 535, Tanzania 304 and Kenya females 95) and 995 controls provided geophagia information. Among controls, ever-geophagia was common in women (Malawi 49%, Kenya 43% and Tanzania 29%) but not in men (10% Malawi, <1% Tanzania). In women, ESCC ORs were 1.25 (95% CI: 0.70, 2.22) for regular versus never geophagia and 0.88 (95% CI: 0.64, 1.22) for pregnancy-only versus never. Findings were stronger based on comparisons of cases with hospital visitor controls and were null using hospital patients as controls. In conclusion, geophagia is too rare to contribute to the male ESCC burden in Africa. In women, the practice is common but we did not find consistent evidence of a link to ESCC. The study cannot rule out selection bias masking modest effects. Physical effects of geophagia do not appear to have a large impact on overall ESCC risk. Research with improved constituent-based geophagia exposure assessment is needed.


Asunto(s)
Neoplasias Esofágicas/epidemiología , Carcinoma de Células Escamosas de Esófago/epidemiología , Pica/epidemiología , Adulto , Anciano , Estudios de Casos y Controles , Neoplasias Esofágicas/etiología , Carcinoma de Células Escamosas de Esófago/etiología , Femenino , Humanos , Kenia/epidemiología , Malaui/epidemiología , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Embarazo , Tanzanía/epidemiología
4.
Int J Cancer ; 147(8): 2131-2141, 2020 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-32306390

RESUMEN

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.


Asunto(s)
Neoplasias de la Mama/epidemiología , Epidemias/estadística & datos numéricos , África/epidemiología , Factores de Edad , Estudios de Cohortes , Femenino , Humanos , Incidencia , Persona de Mediana Edad , Premenopausia/fisiología , Sistema de Registros , Factores de Riesgo
5.
BMC Health Serv Res ; 20(1): 912, 2020 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-33008380

RESUMEN

BACKGROUND: Pathologists face major challenges in breast cancer diagnostics in sub-Saharan Africa (SSA). The major problems identified as impairing the quality of pathology reports are shortcomings of equipment, organization and insufficiently qualified personnel. In addition, in the context of breast cancer, immunohistochemistry (IHC) needs to be available for the evaluation of biomarkers. In the study presented, we aim to describe the current state of breast cancer pathology in order to highlight the unmet needs. METHODS: We obtained information on breast cancer pathology services within population-based cancer registries in SSA. A survey of 20 participating pathology centres was carried out. These centres represent large, rather well-equipped pathologies. The data obtained were related to the known population and breast cancer incidence of the registry areas. RESULTS: The responding pathologists served populations of between 30,000 and 1.8 million and the centres surveyed dealt with 10-386 breast cancer cases per year. Time to fixation and formalin fixation time varied from overnight to more than 72 h. Only five centres processed core needle biopsies as a daily routine. Technical problems were common, with 14 centres reporting temporary power outages and 18 centres claiming to own faulty equipment with no access to technical support. Only half of the centres carried out IHC in their own laboratory. For three centres, IHC was only accessible outside of the country and one centre could not obtain any IHC results. A tumour board was established in 13 centres. CONCLUSIONS: We conclude that breast cancer pathology services ensuring state-of-the-art therapy are only available in a small fraction of centres in SSA. To overcome these limitations, many of the centres require larger numbers of experienced pathologists and technical staff. Furthermore, equipment maintenance, standardization of processing guidelines and establishment of an IHC service are needed to comply with international standards of breast cancer pathology.


Asunto(s)
Neoplasias de la Mama/patología , Patólogos/provisión & distribución , África del Sur del Sahara/epidemiología , Neoplasias de la Mama/epidemiología , Femenino , Humanos , Inmunohistoquímica , Incidencia , Sistema de Registros , Encuestas y Cuestionarios
6.
Clin Infect Dis ; 69(5): 829-835, 2019 08 16.
Artículo en Inglés | MEDLINE | ID: mdl-30452634

RESUMEN

BACKGROUND: With antiretroviral therapy (ART), AIDS-defining cancer incidence has declined and non-AIDS-defining cancers (NADCs) are now more frequent among human immunodeficiency virus (HIV)-infected populations in high-income countries. In sub-Saharan Africa, limited epidemiological data describe cancer burden among ART users. METHODS: We used probabilistic algorithms to link cases from the population-based cancer registry with electronic medical records supporting ART delivery in Malawi's 2 largest HIV cohorts from 2000-2010. Age-adjusted cancer incidence rates (IRs) and 95% confidence intervals were estimated by cancer site, early vs late incidence periods (4-24 and >24 months after ART start), and World Health Organization (WHO) stage among naive ART initiators enrolled for at least 90 days. RESULTS: We identified 4346 cancers among 28 576 persons. Most people initiated ART at advanced WHO stages 3 or 4 (60%); 12% of patients had prevalent malignancies at ART initiation, which were predominantly AIDS-defining eligibility criteria for initiating ART. Kaposi sarcoma (KS) had the highest IR (634.7 per 100 000 person-years) followed by cervical cancer (36.6). KS incidence was highest during the early period 4-24 months after ART initiation. NADCs accounted for 6% of new cancers. CONCLUSIONS: Under historical ART guidelines, NADCs were observed at low rates and were eclipsed by high KS and cervical cancer burden. Cancer burden among Malawian ART users does not yet mirror that in high-income countries. Integrated cancer screening and management in HIV clinics, especially for KS and cervical cancer, remain important priorities in the current Malawi context.


Asunto(s)
Fármacos Anti-VIH/uso terapéutico , Infecciones por VIH/tratamiento farmacológico , Neoplasias/epidemiología , Sistema de Registros , Adolescente , Adulto , Algoritmos , Estudios de Cohortes , Costo de Enfermedad , Registros Electrónicos de Salud , Femenino , Infecciones por VIH/epidemiología , Humanos , Incidencia , Malaui/epidemiología , Masculino , Persona de Mediana Edad , Neoplasias/complicaciones , Prevalencia , Factores de Riesgo , Sarcoma de Kaposi/epidemiología , Neoplasias del Cuello Uterino/epidemiología , Adulto Joven
7.
Int J Cancer ; 141(4): 694-700, 2017 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-28493322

RESUMEN

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.


Asunto(s)
Linfoma de Burkitt/epidemiología , Neoplasias de la Próstata/epidemiología , Sarcoma de Kaposi/epidemiología , Neoplasias del Cuello Uterino/epidemiología , Tumor de Wilms/epidemiología , Adolescente , Adulto , Distribución por Edad , Niño , Preescolar , Femenino , Humanos , Incidencia , Lactante , Malaui/epidemiología , Masculino , Persona de Mediana Edad , Sistema de Registros , Caracteres Sexuales , Adulto Joven
8.
J Infect Dis ; 212(8): 1317-21, 2015 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-25852120

RESUMEN

Children in sub-Saharan Africa continue to acquire and die from cerebral malaria, despite efforts to control or eliminate the causative agent, Plasmodium falciparum. We present a quantitative histopathological assessment of the sequestration of parasitized erythrocytes in multiple organs obtained during a prospective series of 103 autopsies performed between 1996 and 2010 in Blantyre, Malawi, on pediatric patients who died from cerebral malaria and controls. After the brain, sequestration of parasites was most intense in the gastrointestinal tract, both in patients with cerebral malaria and those with parasitemia in other organs. Within cases of histologically defined cerebral malaria, which includes phenotypes termed "sequestration only" (CM1) and "sequestration with extravascular pathology" (CM2), CM1 was associated with large parasite numbers in the spleen and CM2 with intense parasite sequestration in the skin. A striking histological finding overall was the marked sequestration of parasitized erythrocytes across most organs in patients with fatal cerebral malaria, supporting the hypothesis that the disease is, in part, a result of a high level of total-body parasite sequestration.


Asunto(s)
Malaria Cerebral/parasitología , Malaria Falciparum/parasitología , Plasmodium falciparum/aislamiento & purificación , Autopsia , Encéfalo/parasitología , Encéfalo/patología , Estudios de Casos y Controles , Niño , Eritrocitos/parasitología , Tracto Gastrointestinal/parasitología , Tracto Gastrointestinal/patología , Humanos , Malaria Cerebral/mortalidad , Malaria Cerebral/patología , Malaria Falciparum/mortalidad , Malaria Falciparum/patología , Malaui/epidemiología , Carga de Parásitos/métodos , Parasitemia , Estudios Prospectivos , Piel/parasitología , Piel/patología , Bazo/parasitología , Bazo/patología
9.
Cancer Epidemiol ; 92: 102614, 2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-38986356

RESUMEN

"Very hot beverage" (>65°C) consumption is an IARC probable carcinogen and may contribute to the African esophageal cancer burden. We conducted community cross-sectional exposure studies of hot beverage consumption in Kenya and Malawi during 2018-2019, aiming to: (i) implement a detailed measurement protocol incorporating three measurements of sip temperature and volume so as to predict each sip's intra-esophageal liquid temperature (IELT); (ii) examine variations by seasonality, drinking venue and age, including children. 246 participants were included, of whom 236 had drink measurements (52 children and 183 adults). Among adults, mean (SD) temperatures at first sip were 67 (9) and 68 (7) °C in Kenya and Malawi respectively, i.e. 58 and almost 70 % of first sips were > 65 °C. In both countries, adults exhibited a protective habit of smaller sips at higher temperatures (mean 11 mL at first sip), whereas the larger middle sip (20 mL) had the highest IELT (45 °C). The highest temperatures were observed in men and for drinks taken in social settings, whereas we did not detect seasonality or associations with other esophageal cancer risk factors. Measurements were difficult to make for 20 % (8/43) of Kenyan children whose drink was cooled by pouring between cups ('poesha'). Where poesha was not practiced, IELTs were lower in children (especially < 10 years) than in adults, owing to a mean of 8 °C cooler first sip temperature, however 20 % of first sips were > 65 °C. If very hot beverage consumption is an esophageal carcinogen, lowering sip temperatures and volumes in East Africa would form important prevention avenues.

10.
Cell Genom ; 4(3): 100500, 2024 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-38325367

RESUMEN

Large-scale biorepositories and databases are essential to generate equitable, effective, and sustainable advances in cancer prevention, early detection, cancer therapy, cancer care, and surveillance. The Mutographs project has created a large genomic dataset and biorepository of over 7,800 cancer cases from 30 countries across five continents with extensive demographic, lifestyle, environmental, and clinical information. Whole-genome sequencing is being finalized for over 4,000 cases, with the primary goal of understanding the causes of cancer at eight anatomic sites. Genomic, exposure, and clinical data will be publicly available through the International Cancer Genome Consortium Accelerating Research in Genomic Oncology platform. The Mutographs sample and metadata biorepository constitutes a legacy resource for new projects and collaborations aiming to increase our current research efforts in cancer genomic epidemiology globally.


Asunto(s)
Neoplasias , Humanos , Neoplasias/diagnóstico , Genómica , Bases de Datos Factuales , Atención a la Salud , Bancos de Muestras Biológicas
11.
Cancer Immunol Res ; 11(6): 720-731, 2023 06 02.
Artículo en Inglés | MEDLINE | ID: mdl-37058582

RESUMEN

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.


Asunto(s)
Neoplasias , Microambiente Tumoral , Pronóstico , Estudios de Cohortes , Linfocitos Infiltrantes de Tumor , Macrófagos , Neoplasias/patología
12.
Lancet Glob Health ; 10(2): e236-e245, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34921758

RESUMEN

BACKGROUND: The contribution of alcohol to the large burden of oesophageal squamous cell carcinoma (ESCC) in east Africa remains uncertain and difficult to assess owing to complex consumption patterns of traditional and commercial drinks. We aimed to assess whether alcohol drinking, overall and at specific intake levels, contributes to ESCC risk in east Africa. METHODS: We did a hospital-based case-control study in Kenya, Tanzania, and Malawi, which included comprehensive assessment of a variety of locally consumed alcohol that we used to classify drinkers as exclusively low alcohol-by-volume (ABV; <30% ABV) drinkers or drinkers of some high-ABV drinks, as well as the number of drinks consumed, average weekly ethanol intake, and the contribution of each drink type to overall ethanol consumption. Cases were patients aged 18 years and older with incident primary ESCC, confirmed histologically for the majority of cases, and a clinical diagnosis for the remainder. Controls were frequency-matched on age and sex in a 1:1 ratio with cases. The controls were recruited from the same hospitals as cases and included outpatients, inpatients, and hospital visitors who did not have cancer or any other digestive disease. Consenting participants took part in face-to-face interviews in which they were asked whether they had ever consumed alcohol (the primary exposure variable); those who had were asked follow-up questions about their consumption habits for different alcoholic drinks. FINDINGS: 1279 cases and 1346 controls were recruited between Aug 5, 2013, and May 24, 2020, including 430 cases and 440 controls from Kenya, 310 cases and 313 controls from Tanzania, and 539 cases and 593 controls from Malawi. 65 (4·8%) of 1344 cases were excluded. Consistent positive associations with ESCC risk were found for ever having consumed alcohol in Kenyan men and Tanzanian men, and for daily number of drinks and estimated ethanol intake in Kenya, Tanzania (both sexes) and Malawian women. Corresponding population-attributable fractions of ESCC for those reporting ever drinking alcohol (vs never drinking) were 65% (95% CI 52-78) in Kenyan men and 23% (<1-45) in Kenyan women, and 56% (95% CI 36-76) in Tanzanian men and 5% (0-42) in Tanzanian women. Increased risk and population-attributable fractions were almost entirely due to risks in high-ABV drinkers. INTERPRETATION: Alcohol appears to be a substantial contributor to ESCC risk in east Africa, particularly among men, and a large fraction of ESCC could be prevented by cessation or reduction of alcohol consumption. Future studies should consider independent ascertainment of alcohol intake to assess the potential of under-reporting in Malawi. FUNDING: US National Cancer Institute, Wereld Kanker Onderzoek Fonds, and the IARC Environment and Lifestyle Epidemiology Branch. TRANSLATIONS: For the Swahili and Chichewa translations of the abstract see Supplementary Materials section.


Asunto(s)
Consumo de Bebidas Alcohólicas/epidemiología , Neoplasias Esofágicas/epidemiología , Carcinoma de Células Escamosas de Esófago/epidemiología , Adulto , África del Sur del Sahara/epidemiología , Factores de Edad , Anciano , Estudios de Casos y Controles , Femenino , Humanos , Kenia/epidemiología , Masculino , Persona de Mediana Edad , Factores Sexuales , Factores Sociodemográficos
13.
Pan Afr Med J ; 38: 11, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34567338

RESUMEN

INTRODUCTION: the circle of Willis is an anatomical structure of clinical importance particularly in the evaluation of neurovascular diseases. Individuals show considerable variations in the anatomical configuration of the circle of Willis. A cross-sectional study was conducted to determine the distribution of morphological variations of the circle of Willis in Malawians and compare with other ethnic groups. METHODS: brains were collected from twenty-four recently deceased black Malawians during autopsy at Queen Elizabeth Central Hospital, a referral teaching hospital in Blantyre, Malawi and fixed in 10% buffered formalin. Digital images of the interpeduncular region (exposing the circle of Willis) were taken with an 18.4 megapixels camera from the base of the brain. Whole-circle and segmental parameters of the circle of Willis were assessed using the Osiris computer programme and classified based on a 22-type classification scheme. RESULTS: the following morphological variations were observed: hypoplasia, aplasia, asymmetry and accessory vessels. Typical circle of Willis was seen in 26% of the cases. Only six of the original twenty-two types were observed. Consistent with most previous studies, types 1, 3, 4, 6, 8 and 9 were common while types 10-22 were rare. Three variants not previously described in the original scheme (unilateral PcoA aplasia, AcoA duplication, and PcoA aplasia with contralateral PcoA hypoplasia) were observed in this study. CONCLUSION: anatomical variations of the circle of Willis in Malawians seem to be distributed in similar frequencies and patterns as in other more-diverse populations. Circle of Willis variants with potential predilection for atherogenesis and aneurysm formation exist in the Malawian population. These should be considered in clinical practice.


Asunto(s)
Población Negra , Círculo Arterial Cerebral/anatomía & histología , Adolescente , Adulto , Anciano , Cadáver , Niño , Preescolar , Círculo Arterial Cerebral/anomalías , Femenino , Humanos , Malaui , Masculino , Persona de Mediana Edad , Adulto Joven
14.
Cancer Epidemiol Biomarkers Prev ; 30(1): 158-165, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-33033143

RESUMEN

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.


Asunto(s)
Neoplasias de la Próstata/epidemiología , África del Sur del Sahara , Distribución por Edad , Humanos , Masculino , Vigilancia de la Población , Sistema de Registros , Factores de Riesgo
15.
Cancer Res ; 81(10): 2612-2624, 2021 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-33741694

RESUMEN

Epigenetic mechanisms such as aberrant DNA methylation (DNAme) are known to drive esophageal squamous cell carcinoma (ESCC), yet they remain poorly understood. Here, we studied tumor-specific DNAme in ESCC cases from nine high-incidence countries of Africa, Asia, and South America. Infinium MethylationEPIC array was performed on 108 tumors and 51 normal tissues adjacent to the tumors (NAT) in the discovery phase, and targeted pyrosequencing was performed on 132 tumors and 36 NAT in the replication phase. Top genes for replication were prioritized by weighting methylation results using RNA-sequencing data from The Cancer Genome Atlas and GTEx and validated by qPCR. Methylome analysis comparing tumor and NAT identified 6,796 differentially methylated positions (DMP) and 866 differential methylated regions (DMR), with a 30% methylation (Δß) difference. The majority of identified DMPs and DMRs were hypermethylated in tumors, particularly in promoters and gene-body regions of genes involved in transcription activation. The top three prioritized genes for replication, PAX9, SIM2, and THSD4, had similar methylation differences in the discovery and replication sets. These genes were exclusively expressed in normal esophageal tissues in GTEx and downregulated in tumors. The specificity and sensitivity of these DNAme events in discriminating tumors from NAT were assessed. Our study identified novel, robust, and crucial tumor-specific DNAme events in ESCC tumors across several high-incidence populations of the world. Methylome changes identified in this study may serve as potential targets for biomarker discovery and warrant further functional characterization. SIGNIFICANCE: This largest genome-wide DNA methylation study on ESCC from high-incidence populations of the world identifies functionally relevant and robust DNAme events that could serve as potential tumor-specific markers. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/10/2612/F1.large.jpg.


Asunto(s)
Biomarcadores de Tumor/genética , Metilación de ADN , ADN de Neoplasias/genética , Epigénesis Genética , Neoplasias Esofágicas/patología , Carcinoma de Células Escamosas de Esófago/patología , Genoma Humano , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Casos y Controles , ADN de Neoplasias/análisis , Neoplasias Esofágicas/epidemiología , Neoplasias Esofágicas/genética , Carcinoma de Células Escamosas de Esófago/epidemiología , Carcinoma de Células Escamosas de Esófago/genética , Femenino , Estudios de Seguimiento , Regulación Neoplásica de la Expresión Génica , Salud Global , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Pronóstico
16.
Nat Genet ; 53(11): 1553-1563, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34663923

RESUMEN

Esophageal squamous cell carcinoma (ESCC) shows remarkable variation in incidence that is not fully explained by known lifestyle and environmental risk factors. It has been speculated that an unknown exogenous exposure(s) could be responsible. Here we combine the fields of mutational signature analysis with cancer epidemiology to study 552 ESCC genomes from eight countries with varying incidence rates. Mutational profiles were similar across all countries studied. Associations between specific mutational signatures and ESCC risk factors were identified for tobacco, alcohol, opium and germline variants, with modest impacts on mutation burden. We find no evidence of a mutational signature indicative of an exogenous exposure capable of explaining differences in ESCC incidence. Apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like (APOBEC)-associated mutational signatures single-base substitution (SBS)2 and SBS13 were present in 88% and 91% of cases, respectively, and accounted for 25% of the mutation burden on average, indicating that APOBEC activation is a crucial step in ESCC tumor development.


Asunto(s)
Neoplasias Esofágicas/epidemiología , Neoplasias Esofágicas/genética , Carcinoma de Células Escamosas de Esófago/epidemiología , Carcinoma de Células Escamosas de Esófago/genética , Mutación , Desaminasas APOBEC/genética , Adulto , Anciano , Anciano de 80 o más Años , Aldehído Deshidrogenasa Mitocondrial/genética , Brasil/epidemiología , China/epidemiología , Femenino , Humanos , Incidencia , Irán/epidemiología , Masculino , Persona de Mediana Edad , Proteína p53 Supresora de Tumor/genética , Reino Unido/epidemiología , Secuenciación Completa del Genoma
17.
J Glob Oncol ; 4: 1-11, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-30085887

RESUMEN

Purpose Cancer surveillance provides a critical evidence base to guide cancer control efforts, yet population-based coverage in Africa is sparse. Hospital-based registries may help fill this need by providing local epidemiologic data to guide policy and forecast local health care needs. We report the epidemiology of patients with cancer recorded by a de novo hospital-based cancer registry at Kamuzu Central Hospital, Malawi, the sole provider of comprehensive oncology services for half the country and location of a high-volume pathology laboratory. Methods We conducted active case finding across all hospital departments and the pathology laboratory from June 2014 to March 2016. Patient demographics, tumor characteristics, treatment, and HIV status were collected. We describe epidemiology of the cancer caseload, registry design, and costs associated with registry operations. Results Among 1,446 registered patients, Kaposi sarcoma and cervical cancer were the most common cancers among men and women, respectively. Burkitt lymphoma was most common cancer among children. The current rate of pathology confirmation is 65%, a vast improvement in the diagnostic capacity for cancer through the hospital's pathology laboratory. Among leading cancer types, an alarming proportion occurred at young ages; 50% of Kaposi sarcoma and 25% of esophageal, breast, and cervical cancers were diagnosed among those younger than 40 years of age. A systematic, cross-sectional assessment of HIV status reveals a prevalence of 58% among adults and 18% among children. Conclusion We report a high caseload among typically young patients and a significant burden of HIV infection among patients with cancer. In low- and middle-income countries with intermittent, sparse, or nonexistent cancer surveillance, hospital-based cancer registries can provide important local epidemiologic data while efforts to expand population-based registration continue.


Asunto(s)
Infecciones por VIH/epidemiología , VIH/patogenicidad , Femenino , Hospitales de Enseñanza , Humanos , Malaui , Masculino , Persona de Mediana Edad
18.
Cancer Epidemiol ; 53: 119-128, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29414631

RESUMEN

Esophageal squamous cell carcinoma (ESCC) remains the predominant histological subtype of esophageal cancer (EC) in many transitioning countries, with an enigmatic and geographically distinct etiology, and consistently elevated incidence rates in many Eastern and Southern African countries. To gain epidemiological insights into ESCC patterns across the continent, we conducted a systematic review and meta-analysis of male-to-female (M:F) sex ratios of EC age-standardised (world) incidence rates in Africa according to geography, time and age at diagnosis. Data from 197 populations in 36 countries were included in the analysis, based on data from cancer registries included in IARC's Cancer Incidence in Five Continents, Cancer in Africa and Cancer in Sub-Saharan Africa reports, alongside a systematic search of peer-reviewed literature. A consistent male excess in incidence rates overall (1.7; 95% CI: 1.4, 2.0), and in the high-risk Eastern (1.6; 95% CI: 1.4, 1.8) and Southern (1.8; 95% CI: 1.5, 2.0) African regions was observed. Within the latter two regions, there was a male excess evident in 30-39 year olds that was not observed in low-risk regions. Despite possible referral biases affecting the interpretability of the M:F ratios in place and time, the high degree of heterogeneity in ESCC incidence implies a large fraction of the disease is preventable, and directs research enquiries to elucidate early-age exposures among young men in Africa.


Asunto(s)
Neoplasias Esofágicas/epidemiología , Sistema de Registros/estadística & datos numéricos , Adulto , África/epidemiología , Factores de Edad , Anciano , Femenino , Geografía , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Factores de Tiempo , Adulto Joven
19.
J Glob Oncol ; 4: 1-9, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-30241229

RESUMEN

Esophageal cancer is the eighth most common cancer worldwide and the sixth most common cause of cancer-related death; however, worldwide incidence and mortality rates do not reflect the geographic variations in the occurrence of this disease. In recent years, increased attention has been focused on the high incidence of esophageal squamous cell carcinoma (ESCC) throughout the eastern corridor of Africa, extending from Ethiopia to South Africa. Nascent investigations are underway at a number of sites throughout the region in an effort to improve our understanding of the etiology behind the high incidence of ESCC in this region. In 2017, these sites established the African Esophageal Cancer Consortium. Here, we summarize the priorities of this newly established consortium: to implement coordinated multisite investigations into etiology and identify targets for primary prevention; to address the impact of the clinical burden of ESCC via capacity building and shared resources in treatment and palliative care; and to heighten awareness of ESCC among physicians, at-risk populations, policy makers, and funding agencies.


Asunto(s)
Neoplasias Esofágicas/epidemiología , África/epidemiología , Financiación del Capital , Costo de Enfermedad , Neoplasias Esofágicas/etiología , Neoplasias Esofágicas/prevención & control , Neoplasias Esofágicas/terapia , Carcinoma de Células Escamosas de Esófago/epidemiología , Geografía Médica , Política de Salud , Recursos en Salud , Humanos , Cuidados Paliativos , Vigilancia de la Población , Medición de Riesgo , Factores de Riesgo
20.
Malar J ; 6: 102, 2007 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-17683546

RESUMEN

BACKGROUND: Blood group O has been significantly associated with increased placental malaria infection in primiparae and reduced risk of infection in multiparae in the Gambia, an area with markedly seasonal malaria transmission. This study analyses the association between ABO blood group phenotypes in relation to placental malaria pathology and birth outcomes in southern Malawi, an area with perennial malaria transmission. METHODS: A cross-sectional study of 647 mother/child pairs delivering in Montfort Hospital, Chikwawa District between February-June 2004 and January-July 2005 was undertaken. Maternal peripheral and cord blood samples were obtained at delivery. Placental tissue was obtained and malaria histology classified as active, past or no malaria infection. Birth anthropometry was recorded. ABO blood group was measured by agglutination. RESULTS: In primiparae, blood group O was significantly associated with increased risk of active placental infection (OR 2.18, 95% CI 1.15-4.6, p = 0.02) and an increased foetal-placental weight ratio compared to non-O phenotypes (5.68 versus 5.45, p = 0.03) In multiparae blood group O was significantly associated with less frequent active placental infection (OR 0.59, 95% CI 0.36-0.98, p = 0.04), and a higher newborn ponderal index compared to non-O phenotypes (2.65 versus 2.55, p = 0.007). In multivariate regression parity was independently associated with increased risk of placental malaria (active andpast infection) in primiparae with blood group O (p = 0.034) and reduced risk in multiparae with the same phenotype (p = 0.015). CONCLUSION: Parity related susceptibility to placental malaria is associated with the mothers ABO phenotype. This interaction influences foetal and placental growth and could be an important modifying factor for pregnancy outcomes. The biological explanation could relate to sialic acid dependent placental membrane differences which vary with ABO blood group.


Asunto(s)
Sistema del Grupo Sanguíneo ABO/fisiología , Malaria Falciparum/sangre , Malaria Falciparum/inmunología , Paridad/fisiología , Plasmodium falciparum/inmunología , Adolescente , Adulto , Animales , Estudios Transversales , Femenino , Humanos , Malaui , Persona de Mediana Edad , Oportunidad Relativa , Fenotipo , Enfermedades Placentarias/sangre , Enfermedades Placentarias/parasitología , Embarazo , Complicaciones Parasitarias del Embarazo
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