Trends and determinants of the incidence and mortality of cervical cancer in South Africa (1994-2012)

v ACKNOWLEDGEMENTS . vii TABLE OF CONTENTS . ix ABBREVIATIONS AND ACRONYMS . xii LIST OF FIGURES . xiv LIST OF TABLES . xv LIST OF APPENDICES . xvi 1 CHAPTER ONE . 1 1.1 Background . 1 1.2 Problem statement . 2 1.3 Justification of the study . 2 1.4 Literature review . 3 1.4. 1 Pathology of cervical cancer . 3 1.4. 2 Histological types of cervical cancer . 4 1.4. 3 Conceptual framework of the incidence of cervical cancer . 4 1.4. 4 Risk Factors for Cervical Cancer . 5 1.4. 5 Prevention of cervical cancer . 9 1.4. 6 Statistical and epidemiological methods . 11 1.5 Research question . 12 1.6 Research hypotheses . 12 1.7 Research objectives . 13 2 CHAPTER TWO . 15 2.1 Chapter Overview . 15 2.2 Demography of South Africa (study setting of the research) . 15 Cervical cancer in South Africa (1994-2012) Olorunfemi Gbenga x 2.3 Study design . 16 2.4 The setting of the study arms: . 16 2.4. 1 The National Cancer Registry (NCR) . 16 2.4. 2 Statistics South Africa (Stats SA) . 17 2.4. 3 Johannesburg cancer case-control study (JCCCS) . 17 2.5 Target and study population (outcome and exposure variables) . 17 2.5. 1 Incidence and mortality data from NCR and Stats SA . 18 2.5. 2 Cervical cancer risk factors in the JCCCS Data (1995-2010) . 18 2.6 Data processing and statistical analysis . 21 2.6. 1 Data extraction and quality control . 21 2.6. 2 Variables and coding of Stata SA and NCR datasets. 21 2.6. 3 Variable analysis and recoding of JCCCS data . 22 2.7 Objectives One and Two: Cervical cancer trend analysis of incidence (NCR) and mortality (Stats SA) data. 24 2.7. 1 Crude rates . 24 2.7. 2 Population denominators . 24 2.7. 3 Crude mortality rates (CMR) . 25 2.7. 4 Age-standardised rates . 25 2.8 Temporal Trend analysis: Average annual percent change (AAPC). 25 2.9 Objective Three: Annual 5-year relative survival Mortality . 26 2.10 Objective Four: Risk factors of cervical cancer among Black women in Johannesburg, South Africa . 26 2.10. 1 Use of vce robust option and model building. 26 2.11 Ethical considerations . 29 2.12 Future Opportunities for dissemination of the research findings . 29 3 CHAPTER THREE. 30 3.1 Objective One: Trends of Cervical Cancer Incidence in South Africa (1994-2009) . 30 3.1.1 Demographic and histological distribution . 30 3.1.2 Trends in numbers of cervical cancer cases by population group, 1994-2009 . 32 3.1.3 Overall crude and age-standardised incidence rate and by population group, 19942009 . 32 3.1.4 Trends in age-specific incidence rates and by population group, 1994-2009 . 35 Cervical cancer in South Africa (1994-2012) Olorunfemi Gbenga xi 3.1.5 Incidence of major histological types of cervical cancer . 36 3.2 Objective Two: Trends of cervical cancer mortality in South Africa (2004-2012) . 36 3.2.1 Socio-demographic characteristics of deaths from cervical cancer . 36 3.2.2 Trends in numbers of deaths from CC by population group, 2004-2012 . 37 3.2.3 Overall crude and age-standardised mortality rate and by population group, 20042012 . 37 3.2.4 Trends in age-specific mortality rates of cervical cancer and by population group in South Africa (2004-2012) . 39 3.2.5 Temporal trends in cervical cancer mortality in South Africa by province of residence (2004-2012) . 40 3.3 Objective Three: 5-year relative survival rates of cervical cancer in South Africa (2004-2009) . 41 3.4 Objective Four: Cervical cancer risk factors in Black South Africans (JCCCS) . 42 3.4. 1 General characteristics of the Black participants of the JCCCS . 42 3.4. 2 Case-control study I: HIV as major risk factor of cervical cancer. 45 3.4. 3 Case-control study II: Tobacco smoking and alcohol as major risk factors of cervical cancer . 48 3.4. 4 Case-control study III: Sexual, reproductive and hormonal factors as major risk factors of cervical cancer. 51 3.4. 5 Post estimation diagnostics and sensitivity analysis for JCCCS sub-studies. 54 4 CHAPTER FOUR . 56 4.