Anne Korir

Incidence of cancer in Nairobi, Kenya (2004-2008).

Cancer incidence rates are presented for the Nairobi Cancer Registry, a population‐based cancer registry (PBCR) covering the population of the capital city of Kenya (3.2 million inhabitants in 2009). Case finding was by active methods, with standard and checks for accuracy and validity. During the period 2004–2008 a total of 8,982 cases were registered comprising 3,889 men (an age standardized incidence rate (ASR) of 161 per 100,000) and 5,093 women (ASR 231 per 1,00,000). Prostate cancer was the most common cancer in men (ASR 40.6 per 100,000) while breast cancer was the most common among women (ASR 51.7 per 100,000). Cervical cancer ranked the second most common cancer among women in Nairobi with an ASR of 46.1 per 100,000, somewhat lower than those of other registries in East Africa region. Breast and cervical cancers accounted for 44% of all cancers in women. Cancer of the oesophagus was common in both sexes, with a slight excess of cases in men (sex ratio 1.3). Unlike other regions in East Africa, the rate of Kaposi sarcoma was relatively low during the period (men 3.6/100,000; women 2.0/100,000). Although incidence rates cannot be calculated for the early years of the registry, the increase in relative frequency of prostate cancer and declines in frequency of Kaposi sarcoma may indicate underlying trends in the risk of these cancers.

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.

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

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

Developing Clinical Strength-of-Evidence Approach to Define HIV-Associated Malignancies for Cancer Registration in Kenya

Background Sub-Saharan Africa cancer registries are beset by an increasing cancer burden further exacerbated by the AIDS epidemic where there are limited capabilities for cancer-AIDS match co-registration. We undertook a pilot study based on a “strength-of-evidence” approach using clinical data that is abstracted at the time of cancer registration for purposes of linking cancer diagnosis to AIDS diagnosis. Methods/Findings The standard Nairobi Cancer Registry form was modified for registrars to abstract the following clinical data from medical records regarding HIV infection/AIDS in a hierarchal approach at time of cancer registration from highest-to-lowest strength-of-evidence: 1) documentation of positive HIV serology; 2) antiretroviral drug prescription; 3) CD4+ lymphocyte count; and 4) WHO HIV clinical stage or immune suppression syndrome (ISS), which is Kenyan terminology for AIDS. Between August 1 and October 31, 2011 a total of 1,200 cancer cases were registered. Of these, 171 cases (14.3%) met clinical strength-of-evidence criteria for association with HIV infection/AIDS; 69% (118 cases were tumor types with known HIV association – Kaposi’s sarcoma, cervical cancer, non-Hodgkin’s and Hodgkin’s lymphoma, and conjunctiva carcinoma) and 31% (53) were consistent with non-AIDS defining cancers. Verifiable positive HIV serology was identified in 47 (27%) cases for an absolute seroprevalence rate of 4% among the cancer registered cases with an upper boundary of 14% among those meeting at least one of strength-of-evidence criteria. Conclusions/Significance This pilot demonstration of a hierarchal, clinical strength-of-evidence approach for cancer-AIDS registration in Kenya establishes feasibility, is readily adaptable, pragmatic, and does not require additional resources for critically under staffed cancer registries. Cancer is an emerging public health challenge, and African nations need to develop well designed population-based studies in order to better define the impact and spectrum of malignant disease in the backdrop of HIV infection.

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.

Esophageal cancer male to female incidence ratios in Africa: A systematic review and meta-analysis of geographic, time and age trends

Highlights • We conducted a review and meta-analysis of esophageal cancer sex ratios in mainland Africa using data from 197 populations in 36 countries.• We observed a consistent male excess in incidence rates overall and in the high-risk Eastern and Southern African regions.• A male excess was evident in 30–39 year olds in high-risk Eastern and Southern African regions.• Our findings suggest that a substantial fraction of the African EC burden could be avoided by targeting gender-specific exposures.

Research for Actionable Policies: implementation science priorities to scale up non–communicable disease interventions in Kenya

Sujha Subramanian, Joseph Kibachio, Sonja Hoover, Patrick Edwards, Evans Amukoye, Mary Amuyunzu–Nyamongo, Gisela Abbam, Naftali Busakhala, Abigail Chakava, Jonathan Dick, Robai Gakunga, Gladwell Gathecha, Rainer Hilscher, Muhammad Jami Husain, Lydia Kaduka, James Kayima, Alfred Karagu, Dorcas Kiptui, Anne Korir, Nkatha Meme, Breda Munoz, Walter Mwanda, Daniel Mwai, Julius Mwangi, Esther Munyoro, Zachary Muriuki, James Njoroge, Elijah Ogola, Carol Olale, Deborah Olwal–Modi, Rose Rao, Saras Rosin, Onyango Sangoro, Daniel von Rège, David Wata, Pam Williams, Gerald Yonga; Participants from the NCD Symposium in Kenya

Viral-associated malignancies in Africa: are viruses 'infectious traces' or 'dominant drivers'?

Since the discovery of Epstein-Barr virus (EBV) the first human virus associated with cancer in 1964, the number of human malignancies associated with viruses has grown. A review of cancer incidence reveals substantial variation in the incidence of such cancers around the world. In some parts of Africa, the majority of cancers are caused by infectious agents. However, there remain huge challenges in measuring the burden of cancer, especially in sub-Saharan Africa. Despite this limitation, it is clear that viral-associated malignancies are key drivers of cancer incidence rates in Africa. Prevention is available through vaccination for some but development of vaccines for others remains an important the goal.

Stroke Mortality in Kenya’s Public Tertiary Hospitals: A Prospective Facility-Based Study

Background: Despite the increasing global burden of stroke, there are limited data on stroke from Kenya to guide in decision-making. Stroke occurrence in sub-Saharan Africa has been associated with poor health outcomes. This study sought to establish the stroke incidence density and mortality in Kenya’s leading public tertiary hospitals for purposes of informing clinical practice and policy. Methods: This is a prospective study conducted at Kenya’s leading referral hospitals, namely, Kenyatta National Hospital (KNH) and Moi Teaching and Referral Hospital (MTRH). Adult patients with confirmed cases of stroke were recruited from February 2015 to January 2016 and followed up for a minimum period of 1 year. The WHO 2006 Stroke STEPS instrument was used to collect data on incidence and mortality at days 10 and 28 and every 3 months for 24 months. The person-time of follow-up was computed from admission to death, loss to follow-up, or the end of the study. A survival regression analysis was done using the Cox proportional hazards model. Results: A total of 719 patients were recruited (KNH: n = 406 [56.5%]; MTRH: n = 313 [43.5%]). The mean age was 58.6 ± 18.7 years, and the male-to-female ratio was 1: 1.4. Ischemic stroke accounted for 56.1% of the stroke cases. The peak age for stroke was between 50 and 69 years, when 36.3% of the cases occurred. Mortality at day 10 and day 28 was 18.4 and 26.7%, respectively. The inpatient mortality rate was 21.6%. The stroke incidence density was 507 deaths per 1,000 person-years of follow-up. The mean survival time was significantly different between inpatients (13.9 months; 95% CI: 13.0–14.7) and outpatients (18.6 months; 95% CI: 17.2–19.9) (p < 0.001). A 1-year increase in age increased the hazard by 1.8%. Inpatients had a 3.9-fold increase in hazard compared to outpatients. Conclusions: Mortality due to stroke is high, with poor survival observed in the first year after stroke. The risk of death increases with increasing age and duration of hospital stay. There is need for attention to quality of care and long-term needs of stroke patients to mitigate the high mortality rates observed. Public health initiatives aimed at early screening and diagnosis should be enhanced. Further research is recommended to establish the true burden of stroke at the community level to inform appropriate mitigation measures.