Global Health Challenges Social Analysis 76: Lecture 14

Global Health ChallengesSocial Analysis 76: Lecture 14 Harvard University Initiative for Global Health

WHO Election Update • Of 11 candidates, 5 have made it to the short-list: Harvard University Initiative for Global Health

Burden and Trends of Cancers Progress in Treating Cancers Specific Cancers Burden of Cardiovascular Diseases Intervention Options CVD Challenges Harvard University Initiative for Global Health

Cancers Traditionally, cancers have been characterized by the body organ system where they first appear. Cancers affecting the lung, for example, may have different etiologies and appearances. As genetic information accumulates, it is clear that the molecular pathway that is disrupted may be different for cancers that appear to be the same. At the same time cancers in different sites may share the same molecular or genetic origin. Harvard University Initiative for Global Health

How Do We Know About Cancers? Two sources of information about the distribution of cancers in the population: population-based cancer registries and vital registration systems. Interpretation of trends and patterns of cancers is confounded by differences in the ascertainment rate over time in cancers, incomplete follow-up in some developing country sites and changes in classification schemes. Harvard University Initiative for Global Health

Harvard University Initiative for Global Health

Cancers and the Epidemiological Transition Cancer risk is substantially determined by environmental exposures, diet and genetic susceptibility. Much of the heterogeneity in cancer risk across communities is not understood. On average, however, developing countries have higher risks of cancers of the stomach, liver, cervix, mouth, and esophagus and probably prostate. On average, developed countries have higher risks of lung and colon/rectum cancers. Tobacco consumption explains the enormous rise of lung cancer, and a component of mouth oro-pharynx. Harvard University Initiative for Global Health

5-Year Relative and Absolute Survival Cancer literature uses two measures to analyze the impact of cancer diagnosis and treatment: 5-year absolute and relative survival. Absolute survival is the percentage of individuals diagnosed with a cancer alive after 5 years. Relative survival is the percentage of individuals diagnosed with cancer alive after 5 years divided by the percentage of the age-sex matched general population alive after 5 years. Harvard University Initiative for Global Health

New Directions in Cancer Treatment Dramatic increase in understanding of cancer biology and genetics over the last 20 years. Targeted therapy – imatinib (Gleevec) induces nearly complete and sustained remission in patients with early stage chronic myeloid leukemia. Lots of promise for new generation treatments but they may be many years away. Harvard University Initiative for Global Health

Stomach Cancer High incidence and mortality in East Asia. Major decline in stomach cancer incidence and mortality in Western countries over the last 50 years. Many theories that refrigeration of food and the declining use of some preservatives have been important drivers. H.Pylori infection is accepted as a risk for stomach cancer and may account for 40% of stomach cancers worldwide. Harvard University Initiative for Global Health

Liver Cancer High incidence and mortality in Africa, East Asia. Major risk factor is chronic infection with Hepatitis B and Hepatitis C viruses. 85% of cases in developing countries are attributable to these infections. Hepatitis B vaccination is effective and has been recommended as a childhood vaccination to be included in the expanded programme of immunization. GAVI reports 41.6 million children immunized through their programmes. Harvard University Initiative for Global Health

Slide Date: December 03 Countries having introduced HepB vaccine and reported HepB3 coverage, 2002 (141 countries introduced) HepB3 > 80%(71 countries or 37%) HepB3 < 80%(30 countries or 15% ) HepB vaccine introduced but no coverage data reported(40 countries or 21%) HepB vaccine not introduced(51 countries or 27%) (in 5 countries HepB administered for adolescence) Harvard University Initiative for Global Health Source: WHO/UNICEF joint reporting form, 2002 data from 192 WHO member states

Lung Cancer Lung cancer is the most common cancer and the largest cause of cancer mortality. Nearly all variation in lung cancer incidence can be attributed to tobacco smoking. In fact, Peto and Lopez have used the observed lung cancer death rate as a biological index of cumulative tobacco consumption in a population. The main strategy for tackling lung cancer is to reduce tobacco consumption which we will discuss in detail in the lecture on tobacco. Harvard University Initiative for Global Health

Breast Cancer Most common incident cancer in women. Incidence is recorded as higher and increasing in high income countries. Reproductive factors and family history are important risks. 5-year survival has improved from 60% to 89% in the last 50 years in the United States for white populations. Screening with mammography is believed to have contributed to improved 5-year survival by detecting cancers at an earlier stage. Harvard University Initiative for Global Health

Cervical Cancer Cervical cancer is highest in poor developing countries. HPV (selected high risk serotypes) are the main risk factor for cervical cancer. Most young women who are sexually active are infected with HPV. Cervical cancer incidence and mortality have declined substantially over the last 40 years in high-income countries. This decline in part is attributable to cervical cancer screening programs. HPV vaccines have demonstrated efficacy in large-scale trials. Harvard University Initiative for Global Health

Global Cancer Response War on Cancer – National Cancer Institute, International Agency for Research on Cancer (Lyon, part of WHO) Tobacco control efforts – Framework Convention on Tobacco Control Cervical and breast cancer screening included in discussions of the Cairo Reproductive Health agenda Hepatitis B vaccination included in GAVI No other treatment initiatives Harvard University Initiative for Global Health

Ischemic Heart Disease Ischemic heart disease occurs when the muscle of the heart does not receive sufficient oxygen due to total or partial occlusion of the arteries supplying blood to the heart. Lack of oxygen is relative to oxygen consumption so that symptoms of ischemic heart disease often occur when an individual exerts themselves. The classic symptom is chest pain, angina pectoris. A myocardial infarction often called MI, a heart attack, occurs when an area of the heart muscle is destroyed by acute lack of oxygen due to a total occlusion. Harvard University Initiative for Global Health

Cerebrovascular Disease or Stroke Stroke occurs when an area of the brain receives insufficient oxygen and the cells die. Two main forms of stroke: hemorrhagic stroke where a blood vessel in the brain ruptures and thrombotic stroke where a blood vessel is occluded because of a blood clot. For those who survive, stroke causes substantial disability. The disability depends on which part of the cortex has been destroyed. Because of the left and right sides of the cortex, symptoms of stroke often affect one side of the body. Harvard University Initiative for Global Health

EUR C Males AMR A Males AFR D+E females WPR B males WPR B females Harvard University Initiative for Global Health

Tackling Global CVD • Three main strategies: • Tobacco control. • Diet and physical activity modification. • Direct interventions for known major risks: blood pressure and cholesterol. • Are these strategies synergistic or competitive? Harvard University Initiative for Global Health

Quest for the Healthy Diet Wide range of dietary components influence CVD risk: trans-fatty acids, high sodium, high caloric intake, fruits and vegetables, fish oils, etc. Controversies on the evidence: intervention trials have shown different effects than the observational studies e.g. anti-oxidants. How effective are we at changing national diets once the optimal diet has been identified? Harvard University Initiative for Global Health

Interventions Targeting Blood Pressure and Cholesterol • Stepwise reductions of salt content of processed foods with either legislation or voluntary agreements and food labelling • Health education through mass-media • Threshold based treatment eg hypertension >160 mmHg, >140 mmHg etc • Absolute risk based combination therapy – statin, low dose BP lowering and aspirin • The Polypill Harvard University Initiative for Global Health

The polypillaka “The Little Red Heart Pill” aka“The risk pill” • Statin, low-dose aspirin & blood pressure drugs • 65% reduction in heart attack & stroke risk • Very safe and tolerable • ~$20 a year Harvard University Initiative for Global Health

Treatment of IHD • Treatments developed over the last 35 years are effective in reducing the disability associated with angina pectoris and congestive heart failure. Emergency therapy of MI has also reduced the case-fatality rate. • Main treatment strategies: • Pharmacological management of angina, CHF • Pharmacological management of BP, cholesterol, plus aspirin and/or beta-blockers • Revascularization of the heart muscle using angioplasty or coronary artery bypass graft • Emergency revascularization through thrombolytic agents (clot busters) Harvard University Initiative for Global Health

Global Health Challenges Social Analysis 76: Lecture 14