Risk factors for common cancers among patients at Kamuzu Central Hospital in Lilongwe, Malawi: A retrospective cohort study

BACKGROUND Little is known about risk factors for different cancers in Malawi. This study aimed to assess risk factors for and epidemiologic patterns of common cancers among patients treated at Kamuzu Central Hospital (KCH) in Lilongwe, and to determine the prevalence of Human Immunodeficiency Virus (HIV) infection in the same population. METHODS We analysed data from the hospital-based KCH cancer registry, from June 2009 to September 2012, including data from a nested substudy on coinfections among cancer patients. Demographics and behavioural variables, including smoking and alcohol use, were collected through personal interviews with patients. We assessed HIV prevalence across cancer types. The distribution of cancer types was reported overall and by gender. Logistic regression was used to assess risk factors associated with common cancer types. RESULTS Data from 504 registered cancer patients were included-300 (59.5%) were female and 204 (40.5%) were male. Mean age was 49 years (standard deviation, SD = 16). There were 343 HIV-negative patients (71.2%), and 139 (28.8%) were HIV-positive. The commonest cancers were oesophageal (n = 172; 34.5%), cervical (n = 109; 21.9%), and Kaposi's sarcoma (KS) (n = 52; 10.4%). Only 18% of cancer cases were histologically confirmed. Patients with oesophageal cancer were likely to be older than 50 years (odds ratio, OR = 2.22), male (OR = 1.47), and smokers (OR = 2.02). Kaposi's sarcoma patients had the highest odds (OR = 54.4) of being HIV-positive and were also more likely to be male (OR = 6.02) and smokers. Cervical cancer patients were more likely to be HIV-positive (OR = 2.2) and less than 50 years of age. CONCLUSIONS Age, smoking, and HIV are important risk factors for the 3 commonest cancer types (oesophageal, KS, and cervical) at this teaching hospital in Malawi. HIV is the single most important risk factor for Kaposi's sarcoma and cervical cancer.