Black-white differences in cancer risk in Harare, Zimbabwe, during 1991-2010

Gastric cancer in Sub-Saharan Africa - a systematic review of primary data

Introduction

Gastric cancer (GC) is the third leading cause of global cancer-related mortality. Despite the shifting burden of GC to low-and middle-income countries, the data regarding incidence, treatment, and outcomes in these settings are sparse. The primary aim of this systematic review was to aggregate all available data on GC in sub-Saharan Africa (SSA) to describe the variability in incidence across the region.

Methods

Studies reporting population-based primary data on GC in SSA were considered. The inclusion was limited to primary studies published between January 1995 and March 2022 which comprised of adult patients in SSA with GC. Studies without accessible full text in either French or English language were excluded. Unadjusted GC incidence rates with their standard errors for each study were recalculated from the crude numerators and denominators provided in individual studies.

Results

A total of 5,626 articles were identified in the initial search, of which, 69 studies were retained. Reported incidence rates ranged from a high of 5.56 GC cases per 100,000 in Greater Meru Kenya to a low of 0.04 GC cases per 100,000 people in Benin City Nigeria. The overall crude pooled incidence was 1.20 GC cases per 100, 000 (95%CI 1.15-1.26) with a variability of 99.83% (I2 p < 0.001). From the 29 high-quality population-based registry studies the crude pooled incidence was 1.71 GC cases per 100,000 people (95%CI 1.56-21.88) with a variability of 99.60%.

Conclusion

This systemic review demonstrates that GC incidence is highly variable across SSA. The limited data on GC treatment, mortality, and survival presents a significant challenge to providing a complete epidemiologic description of the burden of GC in SSA. There is a need for further robust data collection, exploration, and research studies on cancer care in SSA, with continued assessment of primary data availability.

Expanding the prostate cancer cell line repertoire with ACRJ-PC28, an AR-negative neuroendocrine cell line derived from an African-Caribbean patient

Prostate cell lines from diverse backgrounds are important to addressing disparities in prostate cancer (PCa) incidence and mortality rates among Black men. ACRJ-PC28 was developed from a transrectal needle biopsy and established via inactivation of the CDKN2A locus and simultaneous expression of human telomerase. Characterization assays included growth curve analysis, immunoblots, IHC, 3D cultures, immunofluorescence imaging, confocal microscopy, flow cytometry, WGS, and RNA-Seq. ACRJ-PC28 has been passaged more than 40 times in vitro over 10 months with a doubling time of 45 hours. STR profiling confirmed the novelty and human origin of the cell line. RNA-Seq confirmed the expression of prostate specific genes alpha-methylacyl-CoA racemase (AMACR) and NKX3.1 and Neuroendocrine specific markers synaptophysin (SYP) and enolase 2 (ENO2) and IHC confirmed the presence of AMACR. Immunoblots indicated the cell line is of basal-luminal type; expresses p53 and pRB and is AR negative. WGS confirmed the absence of exonic mutations and the presence of intronic variants that appear to not affect function of AR, p53, and pRB. RNA-Seq data revealed numerous TP53 and RB1 mRNA splice variants and the lack of AR mRNA expression. This is consistent with retention of p53 function in response to DNA damage and pRB function in response to contact inhibition. Soft agar anchorage-independent analysis indicated that the cells are transformed, confirmed by principal component analysis (PCA) where ACRJ-PC28 cells cluster alongside other PCa tumor tissues, yet was distinct. The novel methodology described should advance prostate cell line development, addressing the disparity in PCa among Black men.

Cancer incidence among people living with HIV in Zimbabwe: A record linkage study

Background

People living with HIV (PLWH) are at increased risk of developing cancer. Cancer diagnoses are often incompletely captured at antiretroviral therapy (ART) clinics.

Aim

To estimate the incidence and explore risk factors of cancer in a cohort of PLWH in Harare using probabilistic record linkage (PRL).

Methods

We conducted a retrospective cohort study that included PLWH aged ≥16 years starting ART between 2004 and 2017. We used PRL to match records from the Zimbabwe National Cancer Registry (ZNCR) with electronic medical records from an ART clinic in Harare to investigate the incidence of cancer among PLWH initiating ART. We matched records based on demographic data followed by manual clerical review. We followed PLWH up until first cancer diagnosis, death, loss to follow‐up, or 31 December 2017, whichever came first.

Results

We included 3442 PLWH (64.9% female) with 19 346 person‐years (PY) of follow‐up. Median CD4 count at ART initiation was 169 cells/mm³ (interquartile range [IQR]: 82–275), median age was 36.6 years (IQR: 30.6–43.4). There were 66 incident cancer cases for an overall incidence rate of 341/100 000 PY (95% confidence interval [CI]: 268–434). Twenty‐two of these cases were recorded in the ZNCR only. The most common cancers were cervical cancer (n = 16; 123/100 000 PY; 95% CI: 75–201), Kaposi sarcoma, and lymphoma (both n = 12; 62/100 000 PY; 95% CI: 35–109). Cancer incidence increased with age and decreased with higher CD4 cell counts at ART initiation.

Conclusion

PRL was key to correct for cancer under‐ascertainment in this cohort. The most common cancers were infection‐related types, reinforcing the role of early HIV treatment, human papillomavirus vaccination, and cervical cancer screening for cancer prevention in this setting.

Changes in the Incidence of Cancer in Bulawayo, Zimbabwe over a 50-Year Period

BACKGROUND

The cancer registry of Bulawayo (Zimbabwe) operated for 15 years in the preindependence period (1963-77), and was restarted in 2011. This allows comparison of incidence of cancers over a period of almost 50 years.

METHODS

Age-standardized rates, with SEs, were calculated for 1963-1972 and 2011-2015. Detailed results are presented for those cancers for which there was a significant (P < 0.05) change in the rates between the two periods.

RESULTS

There were declines in the rates of those cancers previously known to be common in East and Southern Africa (esophagus, liver, bladder), and the emergence of cancers associated with "westernization" of lifestyles (breast, prostate, large bowel). Cancers related to infection with HIV-AIDS (Kaposi sarcoma, non-Hodgkin lymphoma, eye cancers) have come to comprise a much larger proportion of the total burden, and cancer of the cervix (also AIDS-related) has shown a large increase in incidence-as elsewhere in sub-Saharan Africa (SSA). More surprising is the decline in cancer of the lung-formerly very high, but by 2011-2015, despite little change in the prevalence of smoking, rates were low-close to the average for SSA. This may relate, in part, to a decline in the numbers of miners, and ex-miners, residing in the city.

CONCLUSIONS

The changes in incidence are largely explained by differences in past exposure to environmental risk factors.

IMPACT

Few datasets from SSA can document temporal changes in the cancer epidemic on the continent. There are some anticipated observations, as well as unexpected findings meriting further investigation.

Disparities in prostate cancer incidence and mortality rates: Solvable or not?

Prostate cancer (PCa) is recognized as a disease possessing not only great variation in its geographic and racial distribution but also tremendous variation in its potential to cause morbidity and death and it, therefore, ought not to be considered a homogenous disease entity. Morbidity and death from PCa are disproportionately higher in men of African ancestry (MAA) who are generally observed to have more aggressive disease and worse outcomes following treatment compared to men of European ancestry (MEA). The higher rates of PCa among MAA relative to MEA appear to be multifactorial and related to inherent differences in biological aggressiveness; a continued lack of awareness of the disease and methods of prevention; a lower prevalence of screen-detected PCa; comparatively lower access to quality healthcare as well as systemic and institutionalized disparities in the administration of optimal care to MAA in developed countries such as the United States of America where high-quality care is available. Even when access to quality healthcare is assured in equal access settings, it appears that MAA still have worse outcomes after PCa treatment stage-for-stage and grade-for-grade compared to MEA, suggesting that, inherent racial, ethnic and biological differences are paramount in predicting poor outcomes. This review has explored the different contributing factors to the current disparities in PCa incidence and mortality rates with emphasis on the incongruence in how research has been conducted in understanding the disease towards developing therapies.

Systematic review and meta-analysis of esophageal cancer in Africa: Epidemiology, risk factors, management and outcomes

BACKGROUND

Esophageal cancer (EC) is associated with a poor prognosis, particularly so in Africa where an alarmingly high mortality to incidence ratio prevails for this disease.

AIM

To provide further understanding of EC in the context of the unique cultural and genetic diversity, and socio-economic challenges faced on the African continent.

METHODS

We performed a systematic review of studies from Africa to obtain data on epidemiology, risk factors, management and outcomes of EC. A non-systematic review was used to obtain incidence data from the International Agency for Research on Cancer, and the Cancer in Sub-Saharan reports. We searched EMBASE, PubMed, Web of Science, and Cochrane Central from inception to March 2019 and reviewed the list of articles retrieved. Random effects meta-analyses were used to assess heterogeneity between studies and to obtain odds ratio (OR) of the associations between EC and risk factors; and incidence rate ratios for EC between sexes with their respective 95% confidence intervals (CI).

RESULTS

The incidence of EC is higher in males than females, except in North Africa where it is similar for both sexes. The highest age-standardized rate is from Malawi (30.3 and 19.4 cases/year/100000 population for males and females, respectively) followed by Kenya (28.7 cases/year/100000 population for both sexes). The incidence of EC rises sharply after the age of 40 years and reaches a peak at 75 years old. Meta-analysis shows a strong association with tobacco (OR 3.15, 95%CI: 2.83-3.50). There was significant heterogeneity between studies on alcohol consumption (OR 2.28, 95%CI: 1.94-2.65) and on low socioeconomic status (OR 139, 95%CI: 1.25-1.54) as risk factors, but these could also contribute to increasing the incidence of EC. The best treatment outcomes were with esophagectomy with survival rates of 76.6% at 3 years, and chemo-radiotherapy with an overall combined survival time of 267.50 d.

CONCLUSION

Africa has high incidence and mortality rates of EC, with preventable and non-modifiable risk factors. Men in this setting are at increased risk due to their higher prevalence of tobacco and alcohol consumption. Management requires a multidisciplinary approach, and survival is significantly improved in the setting of esophagectomy and chemoradiation therapy.

Computational modeling of brain pathologies: the case of multiple sclerosis

The central nervous system is the most complex network of the human body. The existence and functionality of a large number of molecular species in human brain are still ambiguous and mostly unknown, thus posing a challenge to Science and Medicine. Neurological diseases inherit the same level of complexity, making effective treatments difficult to be found. Multiple sclerosis (MS) is a major neurological disease that causes severe inabilities and also a significant social burden on health care system: between 2 and 2.5 million people are affected by it, and the cost associated with it is significantly higher as compared with other neurological diseases because of the chronic nature of the disease and to the partial efficacy of current therapies. Despite difficulties in understanding and treating MS, many computational models have been developed to help neurologists. In the present work, we briefly review the main characteristics of MS and present a selection criteria of modeling approaches.

Global burden of cutaneous melanoma attributable to ultraviolet radiation in 2012

Ultraviolet radiation (UVR) is a strong and ubiquitous risk factor for cutaneous melanoma, emitted naturally by the sun but also artificial sources. To shed light on the potential impact of interventions seeking to reduce exposure to UVR in both high and low risk populations, we quantified the number of cutaneous melanomas attributable to UVR worldwide. Population attributable fractions and numbers of new melanoma cases in adults due to ambient UVR were calculated by age and sex for 153 countries by comparing the current melanoma burden with historical data, i.e., the melanoma burden observed in a population with minimal exposure to UVR. Secondary analyses were performed using contemporary melanoma incidence rates in dark-skinned African populations with low UVR susceptibility as reference. Globally, an estimated 168,000 new melanoma cases were attributable to excess UVR in 2012, corresponding to 75.7% of all new melanoma cases and 1.2% of all new cancer cases. This burden was concentrated in very highly developed countries with 149,000 attributable cases and was most pronounced in Oceania, where 96% of all melanomas (representing 9.3% of the total cancer burden) were attributable to excess UVR. There would be approximately 151,000 fewer melanoma cases worldwide were incidence rates in every population equivalent to those observed in selected low-risk (dark-skinned, heavily pigmented) reference populations. These findings underline the need for public health action, an increasing awareness of melanoma and its risk factors, and the need to promote changes in behavior that decrease sun exposure at all ages.

Diagnosis and Treatment of Kaposi Sarcoma

Kaposi sarcoma (KS) is the most common neoplasm of people living with HIV today. In Sub-Saharan Africa, KS is among the most common cancers in men, overall. Not only HIV-positive individuals present with KS; any immune compromised person infected with KS-associated herpesvirus (KSHV) or human herpesvirus 8 is at risk: the elderly, children in KSHV-endemic areas, and transplant recipients. KS diagnosis is based on detection of the viral protein latency-associated nuclear antigen (LANA) in the biopsy, but not all cases of KS are the same or will respond to the same therapy. Standard KS therapy has not changed in 20 years, but newer modalities are on the horizon and will be discussed.

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.