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

Global patterns and trends in Kaposi sarcoma incidence: a population-based study

BACKGROUND

Kaposi sarcoma is a rare, possibly angioproliferative, tumour. Kaposi sarcoma is one of the most common cancers in people living with HIV and poses a serious public health challenge in regions with high HIV burden. We aim to describe global patterns and population-wide trends in the burden of Kaposi sarcoma.

METHODS

In this population-based study, the incidence and mortality estimates of Kaposi sarcoma from 185 countries and regions in 2020 were extracted from the GLOBOCAN 2020 database. The time trends in Kaposi sarcoma incidence were evaluated using the cancer registry data from Cancer Incidence in Five Continents plus from 1998 to 2012. We did not apply any inclusion or exclusion criteria to the data used in this study. Joinpoint regression was used to evaluate the average annual percentage change (AAPC) to quantify trends in the age-standardised incidence rate (ASIR) of Kaposi sarcoma. Correlation analysis was used to evaluate the relationship between the ASIR or age-standardised mortality rate (ASMR) and Human Development Index (HDI).

FINDINGS

In 2020, the global estimated ASIR of Kaposi sarcoma was 0·39 (per 100 000 people), with an estimated 34 270 newly diagnosed cases (23 413 males and 10 857 females). An estimated 15 086 Kaposi sarcoma deaths were reported (9929 males and 5157 females), corresponding to an ASMR of 0·18 (per 100 000 people). In 2020, Africa accounted for 73·0% (25 010 of 34 270) of the incidence and 86·6% (13 066 of 15 086) of the deaths from Kaposi sarcoma worldwide. There was a significant correlation between the ASIR or ASMR and HDI. The incidence of Kaposi sarcoma increased in males in both Türkiye and the Netherlands. The AAPC was 11·5% (95% CI 3·2-20·4) for males in Türkiye and 2·5% (1·1-3·9) for males in the Netherlands from 1998 to 2012. The incidence of Kaposi sarcoma decreased in White Americans, Israel, Uganda, Costa Rica, Colombia, Canada, and Denmark, from 1998 to 2012.

INTERPRETATION

Kaposi sarcoma is a relatively rare cancer worldwide but is endemic in some countries in southern and eastern Africa. Addressing disparities in health-care resource allocation and improving HIV/AIDS care across different HDI regions might contribute to the prevention of Kaposi sarcoma.

FUNDING

The Natural Science Foundation of China Excellent Young Scientists Fund and the Natural Science Foundation of China International/Regional Research Collaboration Project.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

Population genetic polymorphisms of pharmacogenes in Zimbabwe, a potential guide for the safe and efficacious use of medicines in people of African ancestry

OBJECTIVE

Pharmacogenomics (PGx) is a clinically significant factor in the safe and efficacious use of medicines. While PGx knowledge is abundant for other populations, there are scarce PGx data on African populations and is little knowledge on drug-gene interactions for medicines used to treat diseases common in Africa. The aim of this study was to use a custom-designed open array to genotype clinically actionable variants in a Zimbabwean population. This study also identified some of the commonly used drugs in Zimbabwe and the associated genes involved in their metabolism.

METHODS

A custom-designed open array that covers 120 genetic variants was used to genotype 522 black Zimbabwean healthy volunteers using TaqMan-based single nucleotide polymorphism genotyping. Data were also accessed from Essential Drugs' List in Zimbabwe (EDLIZ), and the medicines were grouped into the associated biomarker groups based on their metabolism. We also estimated the national drug procurement levels for medicines that could benefit from PGx-guided use based on the data obtained from the national authorities in Zimbabwe.

RESULTS

The results demonstrate the applicability of an open-array chip in simultaneously determining multiple genetic variants in an individual, thus significantly reducing cost and time to generate PGx data. There were significantly high frequencies of African-specific variants, such as the CYP2D6*17 and *29 variants and the CYP2B6*18 variant. The data obtained showed that the Zimbabwean population exhibits PGx variations in genes important for the safe and efficacious use of drugs approved by the EDLIZ and are procured at significantly large amounts annually. The study has established a cohort of genotyped healthy volunteers that can be accessed and used in the conduct of clinical pharmacogenetic studies for drugs entering a market of people of predominantly African ancestry.

CONCLUSION

Our study demonstrated the potential benefit of integrating PGx in Zimbabwe for the safe and efficacious use of drugs that are commonly used.

Burden of Kaposi sarcoma according to HIV status: A systematic review and global analysis

In 2020, over 34 000 cases of Kaposi sarcoma (KS) were estimated globally, all attributable to KS herpesvirus (KSHV). Prior to the HIV epidemic, KS already existed in KSHV endemic regions, notably in sub-Saharan Africa (SSA). The HIV epidemic has vastly increased the KS burden. We developed a methodology to provide global estimates of KS burden according to HIV status. A systematic review identified studies reporting HIV prevalence in consecutive KS series. Pooled estimates of HIV prevalence, by country or UN subregion, were used to calculate population-attributable fraction (PAF) and these were applied to IARC's GLOBOCAN 2020 to estimate burden and incidence of HIV-attributable and non-HIV-attributable KS. We identified 55 eligible studies, reporting HIV prevalence ranging from ≤5% to ≥95%. Approximately 80% of KS in SSA was estimated attributable to HIV, vs ~50% in the rest of the world. By applying PAFs to national GLOBOCAN estimates, an estimated 19 560 KS cases attributable to HIV were diagnosed in SSA in 2020 (~80% of the worldwide burden), vs 5064 cases of non-HIV-attributable KS (~60% of the worldwide burden). Incidence of HIV-attributable KS was highest in Southern Africa (6.0 cases per 100 000) and Eastern Africa (3.4), which were also the world regions with highest incidence of non-HIV-attributable KS (0.4 and 1.0 cases per 100 000, respectively). This first systematic effort to produce a global picture of KS burden stratified by HIV status highlights the continuing important burden of HIV-attributable KS in SSA, even in the era of combined antiretroviral therapy.

Scaling Up the Surveillance of Childhood Cancer: A Global Roadmap

The World Health Organization recently launched the Global Initiative for Childhood Cancer aiming to substantially increase survival among children with cancer by 2030. The ultimate goal concerns particularly less developed countries where survival estimates are considerably lower than in high-income countries where children with cancer attain approximately 80% survival. Given the vast gap in high-quality data availability between more and less developed countries, measuring the success of the Global Initiative for Childhood Cancer will also require substantial support to childhood cancer registries to enable them to provide survival data at the population level. Based on our experience acquired at the International Agency for Research on Cancer in global cancer surveillance, we hereby review crucial aspects to consider in the development of childhood cancer registration and present our vision on how the Global Initiative for Cancer Registry Development can accelerate the measurement of the outcome of children with cancer.

The impact of the South African antiretroviral treatment programme on the age-standardised incidence rate of Kaposi sarcoma, 1999-2016: An interrupted time series analysis

OBJECTIVE

The objective of this study was to quantify the impact of the South African antiretroviral treatment programme on the age-standardised incidence rate of Kaposi sarcoma among black South African residents of all ages.

METHODS

We performed an interrupted time series analysis using routinely collected, histologically confirmed surveillance data from the South African National Cancer Registry for the years 1999 to 2016. The analysis was performed using R statistical software. The total number of cases was 29,623 (12,475 females and 17,166 males). The background antiretroviral treatment coverage was less than 1% at the time that the antiretroviral programme was introduced and increased to over 50% in 2016.

RESULTS

In 1999, the age-standardised rates were 1.48 and 2.82 cases per 100,000 per year for black females and males, respectively. These rates increased to 5.52 and 7.46 in 2008 before declining. The antiretroviral treatment programme was started in 2004. Five years after 2008 (nine years after the antiretroviral programme was introduced), the predicted standardised rates were 58.3% and 50.3% lower for females and males, respectively, than what they would have been without the treatment programme.

CONCLUSION

Introduction of the antiretroviral treatment programme was associated with a decrease of over 50% in the predicted age-standardised incidence rates of Kaposi sarcoma.

Global patterns and trends in the incidence of non-Hodgkin lymphoma

PURPOSE

Despite an increasing understanding of the pathology and genetics of non-Hodgkin lymphoma (NHL), global reports on variations in the incidence of NHL remain limited in their number and scope.

METHODS

To provide a situation analysis, national incidence estimates for NHL in 185 countries for the year 2018 were obtained from the GLOBOCAN database. We also used recorded incidence data from Cancer Incidence in Five Continents (CI5) plus for years of diagnosis 1980-2012 to examine temporal trends.

RESULTS

NHL ranked as the 5th to 9th most common cancer in most countries worldwide, with almost 510,000 new cases estimated in 2018. Observed incidence rates of NHL 2008-2012 varied markedly by world region: among males, rates were highest among Israel Jews [age-standardized (world) rate of 17.6 per 100,000), Australia (15.3), US whites (14.5), Canada (13.7), and Portugal (13.3)]. Where data were available, most populations exhibited stable or slightly increasing incidence rates; in North America, parts of Europe, and Oceania the rising incidence rates were generally observed until the 1990s, with a stabilization seen thereafter.

CONCLUSION

Marked variations in NHL incidence rates remain in populations in each world region. Special attention should be given to further etiological research on the role of endemic infections and environmental exposures, particularly in Africa, Asia, and Latin America. To permit internationally comparable statistics, an equal focus on addressing the quality of hematological information in population-based registries is also warranted.

Kaposi sarcoma

Kaposi sarcoma (KS) gained public attention as an AIDS-defining malignancy; its appearance on the skin was a highly stigmatizing sign of HIV infection during the height of the AIDS epidemic. The widespread introduction of effective antiretrovirals to control HIV by restoring immunocompetence reduced the prevalence of AIDS-related KS, although KS does occur in individuals with well-controlled HIV infection. KS also presents in individuals without HIV infection in older men (classic KS), in sub-Saharan Africa (endemic KS) and in transplant recipients (iatrogenic KS). The aetiologic agent of KS is KS herpesvirus (KSHV; also known as human herpesvirus-8), and viral proteins can induce KS-associated cellular changes that enable the virus to evade the host immune system and allow the infected cell to survive and proliferate despite viral infection. Currently, most cases of KS occur in sub-Saharan Africa, where KSHV infection is prevalent owing to transmission by saliva in childhood compounded by the ongoing AIDS epidemic. Treatment for early AIDS-related KS in previously untreated patients should start with the control of HIV with antiretrovirals, which frequently results in KS regression. In advanced-stage KS, chemotherapy with pegylated liposomal doxorubicin or paclitaxel is the most common treatment, although it is seldom curative. In sub-Saharan Africa, KS continues to have a poor prognosis. Newer treatments for KS based on the mechanisms of its pathogenesis are being explored.

Differences in survival among adults with HIV-associated Kaposi's sarcoma during routine HIV treatment initiation in Zomba district, Malawi: a retrospective cohort analysis

Background

The HIV epidemic is a major public health concern throughout Africa. Malawi is one of the worst affected countries in sub-Saharan Africa with a 2014 national HIV prevalence currently estimated at 10% (9.3-10.8%) by UNAIDS. Study reports, largely in the African setting comparing outcomes in HIV patients with and without Kaposi's sarcoma (KS) indicate poor prognosis and poor health outcomes amongst HIV+KS patients. Understanding the mortality risk in this patient group could help improve patient management and care.

Methods

Using data for the 559 adult HIV+KS patients who started ART between 2004 and September 2011 at Zomba clinic in Malawi, we estimated relative hazard ratios for all-cause mortality by controlling for age, sex, TB status, occupation, date of starting treatment and distance to the HIV+KS clinic.

Results

Patients with tuberculosis (95% CI: 1.05-4.65) and patients who started ART before 2008 (95% CI: 0.34-0.81) were at significantly greater risk of dying. A random-effects Cox model with Log-Gaussian frailties adequately described the variation in the hazard for mortality.

Conclusion

The year of starting ART and TB status significantly affected survival among HIV+KS patients. A sub-population analysis of this kind can inform an efficient triage system for managing vulnerable patients.

Rapid Multiplexed Immunoassay for Detection of Antibodies to Kaposi's Sarcoma-Associated Herpesvirus

Diagnosis of KSHV-infected individuals remains a challenge. KSHV prevalence is high in several populations with high prevalence of HIV, leading to increased risk of development of Kaposi’s sarcoma (KS). While current assays are reliable for detecting antibodies to KSHV, none are routinely utilized to identify individuals with KSHV infection and thus at increased risk for KS due to assay complexity, lack of access to testing, and cost, particularly in resource-limited settings. Here we describe the addition of KSHV proteins LANA and K8.1 to a previously evaluated HIV/co-infection multiplexed fluorescence immunoassay system. This study demonstrates assay performance by measuring antibody reactivity for KSHV and HIV-1 in a collection of clinical specimens from patients with biopsy-proven KS and sourced negative controls. The KSHV assay correctly identified 155 of 164 plasma samples from patients with biopsy-proven KS and 85 of 93 KSHV antibody (Ab)-negative samples for a sensitivity of 95.1% and specificity of 91.4%. Assay performance for HIV-1 detection was also assessed with 100% agreement with independently verified HIV-1 Ab-positive and Ab-negative samples. These results demonstrate good sensitivity and specificity for detection of antibody to KSHV antigens, and demonstrate the potential for multiplexed co-infection testing in resource-limited settings to identify those at increased risk for HIV-1-related complications.

Cancers in Young Patients in Uyo (Niger-delta Region of Nigeria): Magnitude of the Problem and Histopathological Prolife

Cancers are thought to be rarer in younger population, but emerging data show an increasing incidence of these diseases. The aim of this study was to evaluate the clinicopathological characteristics of cancer among young patients (≥30 years) in Uyo, Nigeria. All specimens were collected and reviewed during the period January 2007-December 2012; complete clinicopathological data were also considered. A total of 108 cases of proven cancers were diagnosed (3.4%), accounting for 14.1% of all malignancies. A male:female ratio of 1:3.2 was recorded. Among 0-14-year-old patients, the most common malignancy was embryonal cancer (50.0%), followed by non-Hodgkin's lymphoma (18.8%). Carcinoma of the breast and soft tissue sarcoma represent first and second cancers in those patients (40.7% and 13.0% respectively). Carcinoma of uterine cervix and nodal lymphomas were the third and fourth most common cancers respectively (10.2% and 7.4%), significantly higher in the 21-30 years and 0-10 years age groups. Invasive ductal carcinoma, squamous cell carcinoma, Kaposi sarcoma and Hodgkin's lymphoma were the most common histologic types of cancers in breast, uterine cervix, lymph node and soft tissue (79.6%, 90.0%, 44.4%, 50.0% respectively). This study shows that embryonal cancer was the most common malignancy in patients aged 0 to 14, while carcinoma of the breast and soft tissue sarcoma were the two most common cancers in patients from 5 to 30 years-old.

The Kynurenine Pathway of Tryptophan Catabolism and AIDS-Associated Kaposi Sarcoma in Africa

BACKGROUND

Other than Kaposi sarcoma (KS)-associated herpesvirus and CD4 T-cell lymphopenia, the mechanisms responsible for KS in the context of HIV are poorly understood. One recently explored pathway of HIV pathogenesis involves induction of the enzyme indoleamine 2,3-dioxygenase-1 (IDO), which catabolizes tryptophan into kynurenine and several other immunologically active metabolites that suppress T-cell proliferation. We investigated the role of IDO in the development of KS in HIV disease.

METHODS

In a case-control study among untreated HIV-infected Ugandans, cases were adults with KS and controls were without KS. IDO activity was assessed by the ratio of plasma kynurenine to tryptophan levels (KT ratio), measured by liquid chromatography-tandem mass spectrometry.

RESULTS

We studied 631 HIV-infected subjects: 222 KS cases and 409 controls. Non-KS controls had a higher median plasma KT ratio (130, interquartile range: 90 to 190 nM/μM) than KS cases (110, interquartile range: 90 to 150 nM/μM) (P = 0.004). After adjustment for age, sex, CD4 count, and plasma HIV RNA level, subjects with the highest (fourth quartile) plasma KT ratios had a 59% reduction (95% confidence interval: 27% to 77%) in the odds of KS compared with those with the lowest (first quartile) levels. KS was also independently associated with lower CD4 count, higher plasma HIV RNA, and men.

CONCLUSIONS

Among HIV-infected individuals, greater activity of the kynurenine pathway of tryptophan catabolism, as evidenced by higher levels of plasma KT ratio, was associated with lower occurrence of KS. Some consequences of immune activation in HIV infection might actually suppress certain cancers.

Global cancer statistics, 2012

Cancer constitutes an enormous burden on society in more and less economically developed countries alike. The occurrence of cancer is increasing because of the growth and aging of the population, as well as an increasing prevalence of established risk factors such as smoking, overweight, physical inactivity, and changing reproductive patterns associated with urbanization and economic development. Based on GLOBOCAN estimates, about 14.1 million new cancer cases and 8.2 million deaths occurred in 2012 worldwide. Over the years, the burden has shifted to less developed countries, which currently account for about 57% of cases and 65% of cancer deaths worldwide. Lung cancer is the leading cause of cancer death among males in both more and less developed countries, and has surpassed breast cancer as the leading cause of cancer death among females in more developed countries; breast cancer remains the leading cause of cancer death among females in less developed countries. Other leading causes of cancer death in more developed countries include colorectal cancer among males and females and prostate cancer among males. In less developed countries, liver and stomach cancer among males and cervical cancer among females are also leading causes of cancer death. Although incidence rates for all cancers combined are nearly twice as high in more developed than in less developed countries in both males and females, mortality rates are only 8% to 15% higher in more developed countries. This disparity reflects regional differences in the mix of cancers, which is affected by risk factors and detection practices, and/or the availability of treatment. Risk factors associated with the leading causes of cancer death include tobacco use (lung, colorectal, stomach, and liver cancer), overweight/obesity and physical inactivity (breast and colorectal cancer), and infection (liver, stomach, and cervical cancer). A substantial portion of cancer cases and deaths could be prevented by broadly applying effective prevention measures, such as tobacco control, vaccination, and the use of early detection tests.

Prognosis and delay of diagnosis among Kaposi's sarcoma patients in Uganda: a cross-sectional study

Background

In low- and middle-income countries, the association between delay to treatment and prognosis for Kaposi’s sarcoma (KS) patients is yet to be studied.

Methods

This is a prospective study of HIV-infected adults with histologically-confirmed KS treated at the Uganda Cancer Institute (UCI). Standardized interviews were conducted in English or Luganda. Medical records were abstracted for KS stage at admission to UCI. Multivariable logistic regression assessed relationships between diagnostic delay and stage at diagnosis.

Results

Of 161 patients (90% response rate), 69% were men, and the mean age was 34.0 years (SD 7.7). 26% had been seen in an HIV clinic within 3 months, 72% were on antiretroviral therapy, and 26% had visited a traditional healer prior to diagnosis. 45% delayed seeking care at UCI for ≥3 months from symptom onset. Among those who delayed, 36% waited 6 months, and 25% waited 12 months. Common reasons for delay were lack of pain (48%), no money (32%), and distance to UCI (8%). In adjusted analysis patients who experienced diagnostic delay were more likely than those who did not delay to have poor-risk KS stage (OR 3.41, p = 0.002, 95% CI: 1.46-7.45). In adjusted analyses visiting a traditional healer was the only variable associated with greater likelihood of delay (OR 2.69, p = 0.020, 95% CI: 1.17-6.17).

Conclusions

Diagnostic delay was associated with poor-risk stage at diagnosis, and visiting a traditional healer was associated with higher odds of delay. The relationship between traditional and Western medicine presents a critical intervention point to improve KS-related outcomes in Uganda.

Presence of Betapapillomavirus in Kaposi sarcoma lesions

Human herpes virus 8 (HHV 8) is recognized as the necessary cause of Kaposi sarcoma (KS) and in the recent past the human papillomavirus (HPV) has been linked to the development of cutaneous basal cell and squamous cell carcinomas. In a cross sectional study investigating Beta-HPV infections in skin lesions, an unexpected occurrence of HPV DNA was found in KS lesions of HIV infected individuals. Of the 18 KS cases included in the study 16 (89%) had HPV DNA detected. The most common Betapapillomavirus types were HPV14 [15 cases (83.3%)], HPV12 [8 cases (44.4%)], and HPV24 [7 cases (39%)]. Multiple Beta-HPV types were detected in 10 (62.5%) of the participants with HPV DNA positive lesions; of these 7 had a CD4+ count below 350 cells/µl and 3 had CD4+ counts above 350 cells/µl. The presence of Beta-HPV DNA in KS lesions is a newly described phenomenon. Further studies to elucidate the role of Beta-HPV in KS need to be conducted as it is possible that HHV 8 may not be the solitary viral carcinogen in KS tumorigenesis.

Contribution of HIV infection to mortality among cancer patients in Uganda

OBJECTIVE

HIV infection is associated with cancer risk. This relationship has resulted in a growing cancer burden, especially in resource-limited countries where HIV is highly prevalent. Little is known, however, about how HIV affects cancer survival in these settings. We therefore investigated the role of HIV in cancer survival in Uganda.

DESIGN

Retrospective cohort (N = 802).

METHODS

Eligible cancer patients were residents of Kyadondo County, at least 18 years of age at cancer diagnosis, and diagnosed between 2003 and 2010 with one of the following: breast cancer, cervical cancer, non-Hodgkin's lymphoma, Hodgkin's lymphoma, or esophageal cancer. Patients were classified as HIV-infected at cancer diagnosis based on a documented positive HIV antibody test, medical history indicating HIV infection, or an HIV clinic referral letter. The primary outcome, vital status at 1 year following cancer diagnosis, was abstracted from the medical record or determined through linkage to the national hospice database. The risk of death during the year after cancer diagnosis was compared between cancer patients with and without evidence of HIV infection using Cox proportional hazards regression.

RESULTS

HIV-infected cancer patients in Uganda experienced a more than two-fold increased risk of death during the year following cancer diagnosis compared to HIV-uninfected cancer patients [hazard ratio 2.28; 95% confidence interval (CI) 1.61-3.23]. This association between HIV and 1-year cancer survival was observed for both cancers with (hazard ratio 1.56; 95% CI 1.04-2.34) and without (hazard ratio 2.68; 95% CI 1.20-5.99) an infectious cause.

CONCLUSION

This study demonstrates the role of HIV in cancer survival for both cancers with and without an infectious cause in a resource-limited, HIV-endemic setting.