Feasibility of Rapid Case Ascertainment for Cancer in East Africa: An Investigation of Community-Representative Kaposi Sarcoma in the Era of Antiretroviral Therapy

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Introduction

Rapid case ascertainment (RCA) refers to the thorough research-level evaluation of a patient shortly following diagnosis of a particular condition. While RCA can be performed for any disease, it has mainly been used to evaluate potentially rapidly progressive/fatal disease. This is because RCA allows one to perform detailed clinical and laboratory measurements prior to either the demise of the patient or before he/she experiences either a spontaneous or treatment-induced change from his/her condition at time of diagnosis [ 1 , 2 ]. As such, RCA measurements are critical in facilitating research regarding stage of disease at diagnosis (i.e., a key metric for the effectiveness of early detection efforts), determinants of disease occurrence (i.e., etiology), and determinants of prognosis [ 3 ]. Since its origin [ 1 , 4 , 5 ], RCA has predominantly been performed in resource-rich settings, where it is mostly used to study cancer (e.g., pancreatic [ 678 ]). Despite its potential utility, RCA has rarely been used in resource-limited settings, with the exception of selected infectious diseases [ 910111213 ] in which its utility is to decrease spread. To our knowledge, RCA has not been used to study cancer in resource-limited settings, and there are reasons to believe that it may not be as successful as in resource-rich regions. These include delays in return of pathology results; lack of access to therapy and hence rapid fatality; difficulties in reaching patients due to incomplete phone and residential locator information; and potential hesitancy among gravely ill patients to consent for research.

One cancer and resource-limited context in which findings from RCA would be useful to inform policy and facilitate research is HIV-related Kaposi sarcoma (KS) in sub-Saharan Africa. In this region, even with increased antiretroviral therapy (ART) availability for treatment of HIV infection, KS is the fifth most common cancer in all adults [ 14 ]. In addition to being common, survival following KS diagnosis in Africa is also poor; one-year mortality is between 20 to 40% [ 15161718 ]. Advanced stage of KS at time of diagnosis is often hypothesized to explain this high mortality, but population-level description of KS stage at diagnosis is lacking. Increasing availability of ART in Africa [ 19 ], however, suggests that the epidemiology of KS may change as it has in resource-rich settings [ 2021222324 ]. Wider use of ART may change both stage of KS at diagnosis and survival. Yet, if KS continues to occur despite ART, this begs questions as to why. A thorough evaluation of a community-representative sample of patients with KS in Africa as soon as they are diagnosed ― through RCA ― would facilitate research on all these questions.

To evaluate the feasibility of performing RCA for cancer in a resource-limited setting, we endeavored to perform RCA among a community-representative sample of new diagnoses of KS in East Africa. We describe the methods required to establish RCA, the successes, and limitations of the process.