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CANCER SCREENING AND PREVENTION. Dr. Ajay Mehta MBBS, MD, DTCD, DPMR Sr. Consultant & HOD Department of Medical Oncology FORTIS HEALTHCARE. Fortis Hospital, Shalimar Bagh. CANCER SCREENING AND PREVENTION. HEADINGS CANCER FACTS CANCER GLOBAL BURDEN CAUSES OF CANCER
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CANCER SCREENING AND PREVENTION Dr. Ajay Mehta MBBS, MD, DTCD, DPMR Sr. Consultant & HOD Department of Medical Oncology FORTIS HEALTHCARE Fortis Hospital, Shalimar Bagh
CANCER SCREENING AND PREVENTION • HEADINGS • CANCER FACTS • CANCER GLOBAL BURDEN • CAUSES OF CANCER • 7 DANGER SIGNALS • SCREENING DEFINITION • SCREENING BASICS • PRINCIPLES OF SCREENING • COMMONLY SCREENED DIAGNOSIS
CANCER SCREENING AND PREVENTION • CANCER PREVENTION DEFINITION • LEVELS OF PREVENTION • PRIMARY PREVENTION • SECONDARY PREVENTION • TERTIARY PREVENTION • FUTURE TRENDS
FACTS ABOUT CANCER • 70 – 80 % CANCER CASES ARE DETECTED AT LATE STAGE WHEN TREATMENT IS NOT POSSIBLE • EARLY DETECTION OF CANCER HELPS IN COMPLETE CURE OF SOME CANCER • PREVENTION BY TAKING SOME PRECAUTIONARY MEASURES IS THE BEST WAY TO PREVENT CANCER
By 2015, 66 % of all cancers will be in the developing world !
GLOBAL SCENARIO FEMALES MALES
INDIA: SCENARIO Males Females Globocan database
What Is Cancer? • Cancer is a large group of diseases (over 200) characterized by uncontrolled growth and spread of abnormal cells.* *American Cancer Society, Cancer Facts and Figures 2005
NORMAL CELL CHARACTERISTICS: • Metabolism. Strictly controlled & predictable • Maturation & Specialisation. Occurrs before dividing. Strictly controlled. • Reproduction = Cell death • Contact Inhibition. Mechanism for switching off division when in contact with different cells • Recognition. Like cells stay together.
Cancer Cell Characteristics: • Unchecked & Uncontrolled Growth • Loss of contact inhibition • Loss of capacity to differentiate • Increased growth fraction • Chromosomal Instability • Capacity to metastasise • Altered biochemical properties
Normal Cells Vs. Cancer Cells • Cancer cells: • Lose control over growth and multiplication • Do not self-destruct when they become worn out or damaged • Crowd out healthy cells
Size of cancer cells: One million cancer cells = head of a pin One billion cancer cells = a small grape 230 = 1,073,741,824 = 1 billion cells GROWTH OF CANCER CELLS • Cancer cells reproduce every 2-6 weeks. 2-6 weeks 2-6 weeks 2-6 weeks
CAUSES - TOBACCO • CIGARETTE SMOKING IS A MAJOR CAUSE OF CANCER • SMOKING MAY BE – ACTIVE OR PASSIVE – BOTH ARE HARMFUL • CONSUMPTION OF TOBACCO IN FORM OF KHAINI, ZARDA AND GHUTKA ALSO CAUSES CANCER • TOBACCO NOT ONLY CAUSES CANCER BUT ALSO OTHER DISEASES
CAUSES – BETELNUT • BETELNUT CONTAINS CARCINOGENS • THE NUTS KEPT BURRIED IN THE GROUND FOR LOND PERIOD LEADS TO THE GROWTH OF FUNGUS WHICH IS CARCINOGENIC • PEOPLE CONSUMING BETELNUT ALSO HAVE THE HABIT OF CONSUMING TOBACCO
CAUSES - ALCOHOL • ALCOHOL CONSUMPTION LEADS TO CANCER OF ORAL CAVITY, PHARYNX, LARYNX, ESOPHAGUS, STOMACH, LIVER • PEOPLE WHO DRINK ALSO SMOKES FURTHER INCREASING THE RISK OF DEVELOPING CANCER
CAUSES – FAT/FIBRE • HIGH INTAKE OF FAT (ANIMAL) INCREASES THE RISK OF DEVELOPING CANCER (BREAST AND COLON) • DIETARY FIBRE OF PLANT ORIGIN HAS A PROTECTIVE ROLE AGAINST CANCER
CAUSES – BARBEQUED FOOD • HIGH FAT AND HIGH PROTEIN FOOD WHEN GRILLED AT HIGH TEMPARATURE PRODUCES A CHEMICAL KNOWN TO BE HAVING CARCINOGENIC EFFECT • HIGHLY BROWN AND CHARRED FOOD HAS CANCER CAUSING COMPOUNDS
CAUSES - POLLUTION • AIR POLLUTION – MAY ALSO CAUSE CANCER (ASBESTOS) • INDUSTRIAL WORKERS ARE EXPOSED TO VARIOUS CHEMICALS WHICH ARE KNOWN TO BE CARCINOGEN
CAUSES – WATER POLLUTION • WATER MAY CONTAIN A NUMBER OF CANCER CAUSING SUBSTANCE AS THE INDUSTRIES DUMP CHEMICAL DIRECTLY INTO WATER OR BURRY THEM IN THE GROUND
CAUSES – X-RAY • X-RAYS MAY STIMULATE THE DEVELOPMENT OF CANCER • REPEATED X-RAYS SHOULD BE AVOIDED • X-RAY DONE ON PREGNANT WOMEN MAY INCREASE THE FREQUENCY OF CHILDHOOD CANCER
CAUSES - VIRUS • CERTAIN VIRUSES MAY CAUSE CANCER • THESE VIRUSES ARE – HEPATITIS –B & C, EPSTEIN BARR VIRUS, HUMAN PAPILLOMA VIRUS, CMV. Etc. • THESE VIRUSES CAN BE TRANSMITTED BY BLOOD TRANSFUSION, USE OF CONTAMINATED NEEDLES, FROM MOTHER TO CHILD DURING PREGNANCY OR BREAST FEEDING ANDTHROUGH SEXUAL INTERCOURSE
CAUSES - HEREDITY • FEW CANCER LIKE RETINOBLASTOMA (EYE), COLON CANCER ARISING FROM GENETICALLY CAUSED POLYPS • EVEN BREAST CANCER AND ESOPHAGEAL CANCER
HOW TO DETECT DISEASE EARLY SEVEN DANGER SIGNALS • CHANGE IN BLADDER & BOWEL HABITS • SORE THROAT NOT HEALING • UNUSUAL BLEEDING OR DISCHARGE • THICKENING OR LUMP IN BREAST OR ANYWHERE • INDIGESTION AND DIFFICULTY IN SWALLOWING • OBVIOUS CHANGE IN WART OR MOLE • NAGGING COUGH OR HOARSENESS OF VOICE
CANCER SCREENING • Screening is the process whereby Asymptomatic Individuals are Tested to Detect a disease that is YET to be Symptomatic. CRITERIA laid down for • - Disease in question • - Screening test • - Screening problem .
CANCER SCREENING Disease • natural history is well understood. • has a recognizable early stage . • Treatment at early stage is more successful than at late stage . • it is sufficiently common in target population to warrant screening.
CANCER SCREENING Test • Sensitive and specific . • Acceptable . • Safe . • inexpensive.
CANCER SCREENING Programme • adequate facilities for diagnosis in those with a positive test . • high quality of Treatment for screen detected disease . • benefit outweighs physical and psychological harm . • benefit must justify financial cost.
SCREENING TESTS • Universal screening • Screening all individuals of a certain category (e.g. PKU screening in kids) • Case finding • Screening a small group of individuals based on the presence of risk factors (e.g cancer clusters, family members diagnosed with hereditary disease)
SCREENING TESTS • Biases • Lead time bias • Length time bias • Selection bias • Overdiagnosis bias Avoid bias by using Randomized Control Trials (RCTs)
THE PRINCIPLES OF SCREENING • The choice of disease for which to screen; • The nature of the screening test or tests to be used; • The availability of a treatment for those found to have the disease; • The relative costs of the screening
The disease must be an important health problem. • There should be a recognizable latent or early symptomatic stage. • The natural history of the disease, including latent to declared disease, should be adequately understood
SCREENING TESTS • Universal screening • Screening all individuals of a certain category (e.g. PKU screening in kids) • Case finding • Screening a small group of individuals based on the presence of risk factors (e.g cancer clusters, family members diagnosed with hereditary disease
SCREENING TESTS • Adverse effects • Stress and anxiety caused by false positive results • Unnecessary radiation/chemical exposure and test discomfort • Prolonged knowledge of a disease with no treatment • False sense of security over false negative results • Overuse of medical resources
SCREENING TESTS • Adverse effects • Stress and anxiety caused by false positive results • Unnecessary radiation/chemical exposure and test discomfort • Prolonged knowledge of a disease with no treatment • False sense of security over false negative results • Overuse of medical resources
SCREENING TESTS • Biases • Lead time bias • Length time bias • Selection bias • Overdiagnosis bias Avoid bias by using Randomized Control Trials (RCTs)
COMMONLY SCREENED DIAGNOSES • Cancer (Breast, lung, colorectal, prostate, pancreatic, cervical, ovarian, skin, testicular, thyroid) • Cardiovascular (AAA, Blood pressure, Lipid disorders, carotid artery stenosis, PAD) • Infectious disease (HIV, Hep B/C, STDs, Tuberculosis) • Injury and violence (domestic violence, Youth violence/gang activity, seatbelt use) • Mental health/substance abuse (Etoh, illicit drugs, tobacco, depression, suicide risk) • Endocrine/Metabolism (Diabetes, IDA, obesity, physical activity) • MSK –osteoporosis • OB/Gyn (Pre-eclampsia, Rh incompatibility, neural tube defects, asymptomatic bacteruria, Down’s syndrome) • Pediatrics (PKU, sickle cell disease, visual impairment, lead intoxication, hearing loss, dental caries)
INTRODUCTION • CANCER IS PREVENTABLE • 80 – 90% CANCER ARE DUE TO OUR HABITS AND ACTIVITIES • CANCER INVOLVES ALMOST EVERY PARTS OF THE BODY • CANCER CELLS MULTIPLY IN AN UNCONTROLLABLE & HAPAZARD MANNER