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Johannesburg, South Africa

Urban M.,NHLS MRC Cancer Epidemiology Research Group | Urban M.,University of Witwatersrand | Banks E.,Australian National University | Banks E.,The Sax Institute | And 11 more authors.
PLoS Medicine

Background: Oral contraceptives are known to influence the risk of cancers of the female reproductive system. Evidence regarding the relationship between injectable contraceptives and these cancers is limited, especially in black South Africans, among whom injectable contraceptives are used more commonly than oral contraceptives. Methods and Findings: We analysed data from a South African hospital-based case-control study of black females aged 18-79 y, comparing self-reported contraceptive use in patients with breast (n = 1,664), cervical (n = 2,182), ovarian (n = 182), and endometrial (n = 182) cancer, with self-reported contraceptive use in 1,492 control patients diagnosed with cancers with no known relationship to hormonal contraceptive use. We adjusted for potential confounding factors, including age, calendar year of diagnosis, education, smoking, alcohol, parity/age at first birth, and number of sexual partners. Among controls, 26% had used injectable and 20% had used oral contraceptives. For current and more recent users versus never users of oral or injectable contraceptives, the odds ratios (ORs) for breast cancer were significantly increased in users of oral and/or injectable contraceptives (OR 1.66, 95% CI 1.28-2.16, p<0.001) and separately among those exclusively using oral (1.57, 1.03-2.40, p = 0.04) and exclusively using injectable (OR 1.83, 1.31-2.55, p<0.001) contraceptives; corresponding ORs for cervical cancer were 1.38 (1.08-1.77, p = 0.01), 1.01 (0.66-1.56, p = 0.96), and 1.58 (1.16-2.15, p = 0.004). There was no significant increase in breast or cervical cancer risk among women ceasing hormonal contraceptive use ≥10 y previously (p = 0.3 and p = 0.9, respectively). For durations of use ≥5 y versus never use, the ORs of ovarian cancer were 0.60 (0.36-0.99, p = 0.04) for oral and/or injectable contraceptive use and 0.07 (0.01-0.49, p = 0.008) for injectable use exclusively; corresponding ORs for endometrial cancer were 0.44 (0.22-0.86, p = 0.02) and 0.36 (0.11-1.26, p = 0.1). Conclusions: In this study, use of oral and of injectable hormonal contraceptives was associated with a transiently increased risk of breast and cervical cancer and, for long durations of use, with a reduced risk of ovarian and endometrial cancer. The observed effects of injectable and of oral contraceptives on cancer risk in this study did not appear to differ substantially. Please see later in the article for the Editors' Summary. © 2012 Urban et al. Source

Sengayi M.,NHLS MRC Cancer Epidemiology Research Group | Sengayi M.,University of Bern | Babb C.,NHLS MRC Cancer Epidemiology Research Group | Babb C.,University of Witwatersrand | And 4 more authors.
BMC Cancer

Background: HIV infection is a known risk factor for cancer but little is known about HIV testing patterns and the burden of HIV infection in cancer patients. We did a cross-sectional analysis to identify predictors of prior HIV testing and to quantify the burden of HIV in black cancer patients in Johannesburg, South Africa. Methods: The Johannesburg Cancer Case-control Study (JCCCS) recruits newly-diagnosed black cancer patients attending public referral hospitals for oncology and radiation therapy in Johannesburg . All adult cancer patients enrolled into the JCCCS from November 2004 to December 2009 and interviewed on previous HIV testing were included in the analysis. Patients were independently tested for HIV-1 using a single ELISA test . The prevalence of prior HIV testing, of HIV infection and of undiagnosed HIV infection was calculated. Multivariate logistic regression models were fitted to identify factors associated with prior HIV testing. Results: A total of 5436 cancer patients were tested for HIV of whom 1833[33.7% (95% CI=32.5-35.0)] were HIV-positive. Three-quarters of patients (4092 patients) had ever been tested for HIV. The total prevalence of undiagnosed HIV infection was 11.5% (10.7-12.4) with 34% (32.0-36.3) of the 1833 patients who tested HIV-positive unaware of their infection. Men >49 years [OR 0.49(0.39-0.63)] and those residing in rural areas [OR 0.61(0.39-0.97)] were less likely to have been previously tested for HIV. Men with at least a secondary education [OR 1.79(1.11-2.90)] and those interviewed in recent years [OR 4.13(2.62 - 6.52)] were likely to have prior testing. Women >49 years [OR 0.33(0.27-0.41)] were less likely to have been previously tested for HIV. In women, having children <5 years [OR 2.59(2.04-3.29)], hormonal contraceptive use [OR 1.33(1.09-1.62)], having at least a secondary education [OR:2.08(1.45-2.97)] and recent year of interview [OR 6.04(4.45-8.2)] were independently associated with previous HIV testing. Conclusions: In a study of newly diagnosed black cancer patients in Johannesburg, over a third of HIV-positive patients were unaware of their HIV status. In South Africa black cancer patients should be targeted for opt-out HIV testing. © 2015 Sengayi et al.; licensee BioMed Central. Source

Sitas F.,Cancer Epidemiology Research Unit | Egger S.,Cancer Epidemiology Research Unit | Urban M.I.,University of Witwatersrand | Urban M.I.,Mount Sinai School of Medicine | And 13 more authors.
Journal of the National Cancer Institute

Background The role of human papillomavirus (HPV) in the causation of esophageal squamous cell carcinoma is unclear. We examined the associations between esophageal squamous cell carcinoma and 28 centrally measured HPV serological markers in serum from six existing case-control studies conducted in regions with differing Background risks of esophageal cancer. Methods We used centralized multiplex serology to test serum samples from 1561 case subjects and 2502 control subjects from six case-control studies for antibodies to the major HPV capsid protein (L1) and/or the early proteins E6 and/or E7 of eight high-risk, two low-risk, and four cutaneous HPV types. Study-specific odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated using conditional logistic regression with adjustment for smoking, alcohol consumption, and other potential confounders. Pooled odds ratios and 95% confidence intervals were calculated using either a linear mixed-effects approach or a joint fixed-effects approach. All statistical tests were two-sided. ResultsWe found statistically significant associations between esophageal squamous cell carcinoma and antibodies to E6 for HPV16 (OR = 1.89, 95% CI = 1.09 to 3.29, P =. 023) and HPV6 (OR = 2.53, 95% CI = 1.51 to 4.25, P <. 001) but not for other tested HPV types. There were no statistically significant associations between esophageal squamous cell carcinoma and antibodies to E7 for any of the tested HPV types. Simultaneous seropositivity for HPV16 E6 and E7 was rare (four case subjects, two control subjects; OR = 5.57, 95% CI = 0.90 to 34.35; P =. 064). We also found statistically significant associations between esophageal squamous cell carcinoma and capsid antibodies for the high-risk mucosal type HPV33 L1 (OR = 1.30, 95% CI = 1.00 to 1.69; P =. 047) and the low-risk mucosal types HPV6 (OR = 1.22, 95% CI = 1.05 to 1.42; P =. 010) and HPV11 (OR = 1.30, 95% CI = 1.09 to 1.56, P =. 0036). Conclusions We found limited serological evidence of an association between esophageal squamous cell carcinoma and HPV in the populations studied. Although HPV does not appear to be an important risk factor for esophageal squamous cell carcinoma, we cannot exclude the possibility that certain HPV types may be involved in a small subset of cancers. © 2012 The Author. Source

Calle E.E.,American Cancer Society | Gapstur S.M.,American Cancer Society | Patel A.V.,Aviano Cancer Center | Dal Maso L.,Aviano Cancer Center | And 134 more authors.
The Lancet Oncology

Background Smoking has been linked to mucinous ovarian cancer, but its eff ects on other ovarian cancer subtypes and on overall ovarian cancer risk are unclear, and the fi ndings from most studies with relevant data are unpublished. To assess these associations, we review the published and unpublished evidence. Methods Eligible epidemiological studies were identifi ed by electronic searches, review articles, and discussions with colleagues. Individual participant data for 28 114 women with and 94 942 without ovarian cancer from 51 epidemiological studies were analysed centrally, yielding adjusted relative risks (RRs) of ovarian cancer in smokers compared with never smokers. Findings After exclusion of studies with hospital controls, in which smoking could have aff ected recruitment, overall ovarian cancer incidence was only slightly increased in current smokers compared with women who had never smoked (RR 1.06, 95% CI 1.01-1.11, p=0.01). Of 17 641 epithelial cancers with specifi ed histology, 2314 (13%) were mucinous, 2360 (13%) endometrioid, 969 (5%) clear-cell, and 9086 (52%) serous. Smoking-related risks varied substantially across these subtypes (pheterogeneity<0.0001). For mucinous cancers, incidence was increased in current versus never smokers (1.79, 95% CI 1.60-2.00, p<0.0001), but the increase was mainly in borderline malignant rather than in fully malignant tumours (2.25, 95% CI 1.91-2.65 vs 1.49, 1.28-1.73; pheterogeneity=0.01; almost half the mucinous tumours were only borderline malignant). Both endometrioid (0.81, 95% CI 0.72-0.92, p=0.001) and clear-cell ovarian cancer risks (0.80, 95% CI 0.65-0.97, p=0.03) were reduced in current smokers, and there was no signifi cant association for serous ovarian cancers (0.99, 95% CI 0.93-1.06, p=0.8). These associations did not vary signifi cantly by 13 sociodemographic and personal characteristics of women including their body-mass index, parity, and use of alcohol, oral contraceptives, and menopausal hormone therapy. Interpretation The excess of mucinous ovarian cancers in smokers, which is mainly of tumours of borderline malignancy, is roughly counterbalanced by the defi cit of endometrioid and clear-cell ovarian cancers. The substantial variation in smoking-related risks by tumour subtype is important for understanding ovarian carcinogenesis. Source

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