Cancer Incidence following Expansion of HIV Treatment in Botswana

Abstract

BackgroundThe expansion of combination antiretroviral treatment (ART) in southern Africa has dramatically reduced mortality due to AIDS-related infections, but the impact of ART on cancer incidence in the region is unknown. We sought to describe trends in cancer incidence in Botswana during implementation of the first public ART program in Africa.MethodsWe included 8479 incident cases from the Botswana National Cancer Registry during a period of significant ART expansion in Botswana, 2003–2008, when ART coverage increased from 7.3% to 82.3%. We fit Poisson models of age-adjusted cancer incidence and counts in the total population, and in an inverse probability weighted population with known HIV status, over time and estimated ART coverage.FindingsDuring this period 61.6% of cancers were diagnosed in HIV-infected individuals and 45.4% of all cancers in men and 36.4% of all cancers in women were attributable to HIV. Age-adjusted cancer incidence decreased in the HIV infected population by 8.3% per year (95% CI -14.1 to -2.1%). However, with a progressively larger and older HIV population the annual number of cancers diagnosed remained constant (0.0% annually, 95% CI -4.3 to +4.6%). In the overall population, incidence of Kaposi’s sarcoma decreased (4.6% annually, 95% CI -6.9 to -2.2), but incidence of non-Hodgkin lymphoma (+11.5% annually, 95% CI +6.3 to +17.0%) and HPV-associated cancers increased (+3.9% annually, 95% CI +1.4 to +6.5%). Age-adjusted cancer incidence among individuals without HIV increased 7.5% per year (95% CI +1.4 to +15.2%).InterpretationExpansion of ART in Botswana was associated with decreased age-specific cancer risk. However, an expanding and aging population contributed to continued high numbers of incident cancers in the HIV population. Increased capacity for early detection and treatment of HIV-associated cancer needs to be a new priority for programs in Africa.

Temporal trends in the epidemiology of cervical cancer in South Africa (1994–2012)

“…The sharp decline in the age‐specific incidence rates beyond 65 years might be due to poor ascertainment since histological diagnosis may be difficult to obtain in the elderly . As expected, age‐specific mortality rates increased steeply in the elderly …”

Predictors of Timely Access of Oncology Services and Advanced-Stage Cancer in an HIV-Endemic Setting

“…We obtained the number of monthly recorded cancer cases in the catchment of the study facilities [20], and we assumed that this number remained constant during the study period. We also assumed that if all cases obtained specialized cancer care that the cases would be split 70:30 between Princess Marina Hospital and Gaborone Private Hospital (estimated from BPCC enrollment distribution).…”

HIV-associated malignancies in sub-Saharan Africa

“…Perhaps not surprisingly, similar trends to high-income countries are most evident thus far in middle-income countries, where ART coverage and cancer diagnostic infrastructure are better than low-income countries. For instance, in Botswana, ART expansion has resulted in significant decreases in age-specific cancer risk for HIV-infected individuals [15**]. However, just as in resource-rich settings, when declining incidence is coupled to growth and aging of HIV-positive populations, HIVAM burden is static without significant declines.…”

“…Similarly, in both China and Brazil, relative ADC declines and NADC increases are occurring as in high-income countries [16*, 17*]. Conversely, in most of SSA, ADC still dominate with incidence declines most consistently observed for KS, although KS incidence remains high throughout the region and is often among the most frequent cancers overall [15**, 18*, 19*, 20, 21**, 22]. HIVAM are therefore unlikely to recede as a public health problem in LMIC in the near term despite ART scale-up.…”