Danuta Kielkowski

Tobacco attributable deaths in South Africa

Background: In mid 1998, a question “Was the deceased a smoker five years ago?” was introduced on the newly revised South African death notification form. Design: A total of 16 230 new death notification forms from 1998 have been coded, and comparison of the prevalence of smoking among those who died of different causes was used to estimate, by case–control comparisons, tobacco attributed mortality in South Africa. Cases comprised deaths from causes known (from other studies) to be causally associated with smoking, and controls comprised deaths from medical conditions expected to be unrelated to smoking. Those who died from external causes, and from diseases strongly related to alcohol consumption, were excluded. Subjects: Reports were available from 5340 deceased adults (age 25+), whose smoking status was given by a family member. Results: Significantly increased risks were found for deaths from tuberculosis (odds ratio (OR) 1.61, 95% confidence interval (CI) 1.23 to 2.11), chronic obstructive pulmonary disease (COPD) (OR 2.5, 95% CI 1.9 to 3.4), lung cancer (OR 4.8, 95% CI 2.9 to 8.0), other upper aerodigestive cancer (OR 3.0, 95% CI 1.9 to 4.9) and ischaemic heart disease (OR 1.7, 95% CI 1.2 to 2.3). Conclusion: If smokers had the same death rate as non-smokers, 58% of lung cancer deaths, 37% of COPD deaths, 20% of tuberculosis deaths, and 23% of vascular deaths would have been avoided. About 8% of all adult deaths in South Africa (more than 20 000 deaths a year) were caused by smoking.

Differences among the coloured, white, black, and other South African populations in smoking-attributed mortality at ages 35-74 years: a case-control study of 481,640 deaths.

BACKGROUNDnThe full eventual effects of current smoking patterns cannot yet be seen in Africa. In South Africa, however, men and women in the coloured (mixed black and white ancestry) population have smoked for many decades. We assess mortality from smoking in the coloured, white, and black (African) population groups.nnnMETHODSnIn this case-control study, 481,640 South African notifications of death at ages 35-74 years between 1999 and 2007 yielded information about age, sex, population group, education, smoking 5 years ago (yes or no), and underlying disease. Cases were deaths from diseases expected to be affected by smoking; controls were deaths from selected other diseases, excluding only HIV, cirrhosis, unknown causes, external causes, and mental disorders. Disease-specific case-control comparisons yielded smoking-associated relative risks (RRs; diluted by combining some ex-smokers with the never-smokers). These RRs, when combined with national mortality rates, yielded smoking-attributed mortality rates. Summation yielded RRs and smoking-attributed numbers for overall mortality.nnnFINDINGSnIn the coloured population, smoking prevalence was high in both sexes and smokers had about 50% higher overall mortality than did otherwise similar non-smokers or ex-smokers (men, RR 1·55, 95% CI 1·43-1·67; women, 1·49, 1·38-1·60). RRs were similar in the white population (men, 1·37, 1·29-1·46; women, 1·51, 1·40-1·62), but lower among Africans (men, 1·17, 1·15-1·19; women, 1·16, 1·13-1·20). If these associations are largely causal, smoking-attributed proportions for overall male deaths at ages 35-74 years were 27% (5608/20,767) in the coloured, 14% (3913/28,951) in the white, and 8% (20,398/264,011) in the African population. For female deaths, these proportions were 17% (2728/15,593) in the coloured, 12% (2084/17,899) in the white, and 2% (4038/205,623) in the African population. Because national mortality rates were also substantially higher in the coloured than in the white population, the hazards from smoking in the coloured population were more than double those in the white population.nnnINTERPRETATIONnThe highest smoking-attributed mortality rates were in the coloured population and the lowest were in Africans. The substantial hazards already seen among coloured South Africans suggest growing hazards in all populations in Africa where young adults now smoke.nnnFUNDINGnSouth African Medical Research Council, UK Medical Research Council, Cancer Research UK, British Heart Foundation, New South Wales Cancer Council.

The relation between fibrosis of hilar lymph glands and the development of parenchymal silicosis

The necropsy findings on the cardiorespiratory organs of 849 South African gold miners were analysed to test the hypothesis that fibrosis of the hilar lymph glands predisposes to the development of parenchymal silicotic nodules. Four hundred and eighty three cases had fibrosed glands, 34% of which also had parenchymal silicosis. By comparison, of 238 cases with silicosis, 88% had fibrosed glands. The proportion of cases with both silicosis and fibrosed glands, as well as those with gland fibrosis only, increased with increasing duration of exposure. As far as can be ascertained from a necropsy series such as this, it is possible that fibrosis of the lymph glands may predispose to the development of lung parenchymal silicosis.

Racial Comparison of Receptor-Defined Breast Cancer in Southern African Women: Subtype Prevalence and Age–Incidence Analysis of Nationwide Cancer Registry Data

Background: Receptor-defined breast cancer proportions vary across Africa. They have important implications for survival prospects and research priorities. Methods: We studied estrogen receptor (ER), progesterone receptor (PR), and HER2 receptor statuses in two multiracial Southern African countries with routine diagnostic immunohistochemistry. A total of 12,361 women with histologically confirmed breast cancer diagnosed at age ≥20 years during (i) 2009–2011 from South Africas national cancer registry (public sector) and (ii) 2011–2013 from Namibias only cancer hospital were included. Crude, age, and age + laboratory–adjusted ORs of receptor status were analyzed using logistic regression, and age–incidence curves were analyzed using Poisson regression. Results: A total of 10,047 (81%) women had known ER status. Ranking of subtypes was consistent across races: ER+/PR+HER2− was most common (race-specific percentage range, 54.6%–64.8%), followed by triple-negative (17.4%–21.9%), ER+/PR+HER2+ (9.6%–13.9%), and ER−PR−HER2+ (7.8%–10.9%). Percentages in black versus white women were 33.8% [95% confidence (CI), 32.5–35.0] versus 26.0% (24.0–27.9) ER−; 20.9% (19.7–22.1) versus 17.5% (15.4–19.6) triple-negative; and 10.7% (9.8–11.6) versus 7.8% (6.3–9.3) ER−PR−HER2+. Indian/Asian and mixed-ancestry women had intermediate values. Age–incidence curves had similar shapes across races: rates increased by 12.7% per year (12.2–13.1) across ER subtypes under the age of 50 years, and thereafter slowed for ER+ (1.95%) and plateaued for ER− disease (−0.1%). Conclusions: ER+ breast cancer dominates in all Southern African races, but black women have a modest excess of aggressive subtypes. Impact: On the basis of the predominant receptor-defined breast tumors in Southern Africa, improving survival for the growing breast cancer burden should be achievable through earlier diagnosis and appropriate treatment. Cancer Epidemiol Biomarkers Prev; 23(11); 2311–21. ©2014 AACR.

Cor pulmonale and silicosis: a necropsy based case-control study.

The presence of cor pulmonale at death in relation to other factors such as emphysema, silicosis, and thromboembolism was analysed in a case-control study of 732 South African gold miners. Marked emphysema was the highest risk factor with an odds ratio of 21.32 (95% confidence interval (95% CI) 5.02-90.7), then extensive silicosis (OR 4.95, 95% CI 2.92-8.38) and thromboembolic disease (OR 1.92, 95% CI 1.37-2.69). Age and smoking were not significant predictors of cor pulmonale.

Childhood cancer incidence patterns by race, sex and age for 2000-2006: a report from the South African National Cancer Registry.

Higher childhood cancer incidence rates are generally reported for high income countries although high quality information on descriptive patterns of childhood cancer incidence for low or middle income countries is limited, particularly in Sub‐Saharan Africa. There is a need to quantify global differences by cancer types, and to investigate whether they reflect true incidence differences or can be attributed to under‐diagnosis or under‐reporting. For the first time, we describe childhood cancer data reported to the pathology report‐based National Cancer Registry of South Africa in 2000–2006 and compare our results to incidence data from Germany, a high income country. The overall age‐standardized incidence rate (ASR) for South Africa in 2000–2006 was 45.7 per million children. We observed substantial differences by cancer types within South Africa by racial group; ASRs tended to be 3–4‐fold higher in South African Whites compared to Blacks. ASRs among both Black and White South Africans were generally lower than those from Germany with the greatest differences observed between the Black population in South Africa and Germany, although there was marked variation between cancer types. Age‐specific rates were particularly low comparing South African Whites and Blacks with German infants. Overall, patterns across South African population groups and in comparison to Germans were similar for boys and girls. Genetic and environmental reasons may probably explain rather a small proportion of the observed differences. More research is needed to understand the extent to which under‐ascertainment and under‐diagnosis of childhood cancers drives differences in observed rates.

Record linkage to correct under-ascertainment of cancers in HIV cohorts: The Sinikithemba HIV clinic linkage project.

The surveillance of HIV‐related cancers in South Africa is hampered by the lack of systematic collection of cancer diagnoses in HIV cohorts and the absence of HIV status in cancer registries. To improve cancer ascertainment and estimate cancer incidence, we linked records of adults (agedu2009≥u200916 years) on antiretroviral treatment (ART) enrolled at Sinikithemba HIV clinic, McCord Hospital in KwaZulu‐Natal (KZN) with the cancer records of public laboratories in KZN province using probabilistic record linkage (PRL) methods. We calculated incidence rates for all cancers, Kaposi sarcoma (KS), cervix, non‐Hodgkins lymphoma and non‐AIDS defining cancers (NADCs) before and after inclusion of linkage‐identified cancers with 95% confidence intervals (CIs). A total of 8,721 records of HIV‐positive patients were linked with 35,536 cancer records. Between 2004 and 2010, we identified 448 cancers, 82% (nu2009=u2009367) were recorded in the cancer registry only, 10% (nu2009=u200943) in the HIV cohort only and 8% (nu2009=u200938) both in the HIV cohort and the cancer registry. The overall cancer incidence rate in patients starting ART increased from 134 (95% CI 91–212) to 877 (95% CI 744–1,041) per 100,000 person‐years after inclusion of linkage‐identified cancers. Incidence rates were highest for KS (432, 95% CI 341–555), followed by cervix (259, 95% CI 179–390) and NADCs (294, 95% CI 223–395) per 100,000 person‐years. Ascertainment of cancer in HIV cohorts is incomplete, PRL is both feasible and essential for cancer ascertainment.

Erratum to “Prostate Cancer in South Africa: Pathology Based National Cancer Registry Data (1986–2006) and Mortality Rates (1997–2009)”

Prostate cancer is one of the most common male cancers globally; however little is known about prostate cancer in Africa. Incidence data for prostate cancer in South Africa (SA) from the pathology based National Cancer Registry (1986–2006) and data on mortality (1997–2009) from Statistics SA were analysed. World standard population denominators were used to calculate age specific incidence and mortality rates (ASIR and ASMR) using the direct method. Prostate cancer was the most common male cancer in all SA population groups (excluding basal cell carcinoma). There are large disparities in the ASIR between black, white, coloured, and Asian/Indian populations: 19, 65, 46, and 19 per 100 000, respectively, and ASMR was 11, 7, 52, and 6 per 100 000, respectively. Prostate cancer was the second leading cause of cancer death, accounting for around 13% of male deaths from a cancer. The average age at diagnosis was 68 years and 74 years at death. For SA the ASIR increased from 16.8 in 1986 to 30.8 in 2006, while the ASMR increased from 12.3 in 1997 to 16.7 in 2009. There has been a steady increase of incidence and mortality from prostate cancer in SA.

Trends in mesothelioma mortality rates in South Africa: 1995–2007

Objective In 1984, South Africa had one of the highest mesothelioma rates in the world. The objective of this analysis was to calculate mesothelioma mortality rates in the South African population from 1995 to 2007. Methods Annual mortality data and midyear population estimates were used to compute mortality rates by age group and gender for each year. The WHO World Standard Population was used as the reference population to calculate age-adjusted rates. Poisson regression models were used to test for trends. Results In total, 2509 deaths due to mesothelioma were identified in the study period: 1920 in men and 588 in women. There were no significant trends in mesothelioma mortality rates: age-adjusted mortality rates fluctuated from 11 to 16 and from 3 to 5 per million per year for men and women, respectively. Conclusion These mortality rates are much lower than expected, given the historical production and use of, and high exposure to, asbestos in South Africa. Possible reasons for this are discussed, including the effect of HIV which has been instrumental in reducing the life expectancy of South Africans in the last two decades. Asbestos-exposed individuals may not live long enough to develop mesothelioma. Competing causes of death need to be taken into account when constructing models to predict mesothelioma mortality rates.

Survival of patients with Kaposi’s sarcoma in the South African antiretroviral treatment era: A retrospective cohort study

BACKGROUNDnWhen South Africa (SA) implemented its antiretroviral therapy (ART) programme in 2004, the model for treating HIV-positive Kaposis sarcoma (KS) patients shifted from symptomatic palliation to potential cure.nnnOBJECTIVEnTo evaluate survival and changes over time in AIDS-KS patients treated at a tertiary academic hospital oncology unit (the Steve Biko Academic Hospital medical oncology unit) in Pretoria, SA, in the context of ART availability in SA.nnnMETHODSnWe conducted a retrospective review of electronic and paper records of KS patients who accessed cancer care between May 2004 and September 2012. We used Kaplan-Meier survival functions to estimate 1- and 2-year survival, and Cox regression models to identify changes over time and prognostic factors.nnnRESULTSnOur study included 357 AIDS-KS patients, almost all of whom were black Africans (n=353, 98.9%); 224 (62.7%) were men. The median age at cancer diagnosis was 37 (interquartile range (IQR) 30 - 43) years, and the median baseline CD4+ count was 242 (IQR 130u2005- 403)xa0cells/µL. Most patients received ART (n=332, 93.0%) before or after KS diagnosis; 169 (47.3%) were treated with chemotherapy and 209 (58.6%) with radiation therapy. Mortality was 62.7% lower (adjusted hazard ratio (HR) 0.37, 95% confidence interval (CI) 0.19 - 0.73) in the late (2009 - 2012) than in the early (2004 - 2008) ART period. Receiving chemotherapy (adjusted HR 0.3, 95% CI 0.15 - 0.61) and poor-risk AIDS Clinical Trials Group KS stage (adjusted HR 2.88, 95% CI 1.36 - 6.09) predicted mortality.nnnCONCLUSIONSnOur results show that large national ART roll-out programmes can successfully reduce KS-related mortality at the individual patient level. If ART coverage is extended, KS-associated morbidity and mortality are likely to drop.