Eric Chokunonga

Cancer incidence in the African population of Harare, Zimbabwe : Second results from the cancer registry 1993-1995

The data of the population‐based cancer registry in Harare, Zimbabwe, for 1993–1995 are presented and compared with those from 1990–1992. The most significant change in rates is the striking increase in the incidence of Kaposis sarcoma (KS) in both men and women, compatible with the evolution of the AIDS epidemic in sub‐Saharan Africa. The incidence of KS doubled in both sexes and now accounts for 31.1% of registered cancers. It has overtaken breast cancer to become the second most common tumour in African women, after cervical cancer, and is now one of the leading childhood tumours, accounting for 10.3% of cancers recorded in children (ages 0–14). With the exception of KS, the incidence and pattern of occurrence of the other malignant neoplasms changed little during the observed 6 years. Int. J. Cancer 85:54–59, 2000.

Aids and cancer in Africa: the evolving epidemic in Zimbabwe.

BACKGROUND Zimbabwe is severely affected by the AIDS epidemic, and many cancers in African populations are related to infectious agents. OBJECTIVE To study the current pattern, and short-term changes in incidence, of cancers related to infectious agents (and especially to HIV), with respect to the evolving epidemic of AIDS. METHODS Analysis of data on the African population of Harare, Zimbabwe, from the Zimbabwe Cancer Registry, for the period 1990-1995. Comparison with data on prevalence of HIV seropositivity, and notifications of AIDS. RESULTS Comparing results from 1993-1995 with those for 1990-1992 shows a continuing increase in the incidence of Kaposis sarcoma with a doubling of the rates in both men and women. A dramatic increase in the incidence of squamous cell tumours of the conjunctiva was also observed, as well as a significant increase in the incidence of non-Hodgkins lymphoma in women. There was no apparent increase in risk for Hodgkins disease, myeloma, liver cancer, or cancer of the cervix. CONCLUSIONS The AIDS epidemic has had a dramatic effect on the profile of cancer. The changes in incidence involve several cancers previously linked to AIDS in North America and Europe.

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.

Cancer survival in a southern African urban population.

This paper provides the first comprehensive population based cancer survival estimates from the African continent. Five‐year absolute and relative survival estimates are presented for black and white Zimbabwean patients diagnosed with cancer in Harare, Zimbabwe between the years 1993 and 1997. The survival of black Zimbabwean cancer patients are among the lowest ever reported from population based cancer registries. For most cancer sites, white Zimbabwean patients have much higher survival than black Zimbabweans, except for lung and colorectal cancer, for which the estimates are similarly poor. Race specific comparisons to cancer patients in the United States show that Zimbabwean patients have much lower survival than American cancer patients and that the gap between black Zimbabwean patients and black American patients is broader than between white Zimbabwean and white American patients. Access to and the ability to pay for medical care may be a very important barrier to better survival for the majority of black Zimbabwean patients and the most important cause for the very low cancer survival in this population.

The incidence of oesophageal cancer in Eastern Africa: Identification of a new geographic hot spot?

The incidence of oesophageal cancer (OC) varies geographically, with more than 80% of cases and deaths worldwide occurring in developing countries. The aim of this study is to characterize the disease burden of OC in four urban populations in Eastern Africa, which may represent a previously undescribed high-incidence area. Data on all cases of OC diagnosed between 2004 and 2008 were obtained from four population-based cancer registries in: Blantyre, Malawi; Harare, Zimbabwe; Kampala, Uganda; and Nairobi, Kenya. Age-standardized incidence rates (ASRs) were calculated for each population, and descriptive statistics for incident cases were determined. In Blantyre, 351 male (59%) and 239 (41%) female cases were reported, with ASRs of 47.2 and 30.3. In Harare, 213 male (61%) and 134 (39%) female cases were reported, with ASRs of 33.4 and 25.3, respectively. In Kampala, 196 male (59%) and 137 female (41%) cases were reported, with ASRs of 36.7 and 24.8. In Nairobi, 323 male (57%) and 239 female (43%) cases were reported, with ASRs of 22.6 and 21.6. Median age at diagnosis was significantly different among the four populations, ranging from 50 years in Blantyre to 65 years in Harare (p<0.0001). Except in Nairobi, incidence among males was significantly higher than among females (p<0.01). Squamous cell OC was the predominant histologic subtype at all sites. ASRs at all four sites were remarkably higher than the mean worldwide ASR. Investigation to evaluate potential etiologic effects of dietary, lifestyle, environmental, and other factors impacting the incidence in this region is needed.

Survival of cervix cancer patients in Harare, Zimbabwe, 1995–1997

The survival experience of 284 patients with cancer of the cervix uteri registered by the population‐based Zimbabwe National Cancer Registry in 1995–1997 is described. The vital status of these subjects was established by linkage with death registration and by retrieval of patient files from medical records departments. Untraced patients were contacted at home. Of the 284, 177 (62.3%) were dead and 76 (26.8%) were alive at the closing date of the study (31 December 1999), with only 31 cases (10.9%) lost to follow‐up. Overall observed and relative survival at 3 years were 44.2% and 45.2%, respectively. Half of the cases (139) had been referred and treated in the radiotherapy department. Survival was significantly greater in the first 3 years for patients who received radiotherapy treatment compared to those that had not, but this difference had disappeared by the fourth year of follow‐up. Many cases presented late (distant metastasis), and extent of disease was an important determinant of survival; cases with metastases had a risk of death some 3 times that of patients with localized disease. The results demonstrate the importance of earlier diagnosis and availability of effective treatment in the African context.

Cancer in the European population of Harare, Zimbabwe, 1990-1992

The data presented from the population‐based cancer registry in Harare, Zimbabwe, represent the first information on the incidence of cancer in a population of European origin living in Southern Africa for over 30 years. Their cancer pattern is more or less typical of white populations of high socio‐economic status living in Europe or North America, with elevated incidence rates of breast cancer, large‐bowel cancer and, in women, lung cancer. However, there are also several unusual features, with extremely high incidence rates of skin cancers, including melanomas, and higher rates of liver and bladder cancer than normally seen in white populations.

Kaposi sarcoma trends in Uganda and Zimbabwe: A sustained decline in incidence?

Trends in Kaposi sarcoma (KS) incidence over four decades were described for Zimbabwe and Uganda. KS data were retrieved from the population‐based cancer registries of Bulawayo (1963–1971) and Harare (1990–2005), Zimbabwe and Kyadondo, Uganda (1960–1971 and 1991–2007). Joinpoint regression models were used to analyze time trends of KS incidence. Trends were compared to HIV/AIDS trends and were also described as rates versus birth cohort by age. In both countries, an increased incidence of KS accompanied the emergence of the HIV/AIDS epidemic (p‐value < 0.0001). In Zimbabwe, KS incidence (both sexes, all ages) changed in parallel to that of HIV/AIDS prevalence, whereas in Uganda, despite an observed decrease in HIV/AIDS prevalence since 1992, we observed a decrease in KS incidence in men younger than 50 years (Annual Percent Change, APC after 1991 = −4.5 [−5.6; −3.4], p‐value < 0.05) but not in men aged >50 years (APC after 1991 = 1.0 [−2.8; 5.0]) nor in women (APC = 1.0 [−0.6; 2.6]). In both populations, a period effect at older ages was observed, with initial increases in incidence in men followed subsequently by a downturn in rates of the same magnitude. The uniformly declining rates in younger men (aged less than 30 years) suggested that a recent cohort effect was also in operation with a reduced risk in generations born after the mid‐1950s in Uganda and in the mid‐1960s in Zimbabwe. The combined introduction of antiretroviral therapy and effective prevention programmes against HIV/AIDS appeared to be the key contributors to the KS decline observed in both Uganda and Zimbabwe.

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.

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

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.