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					Routine General Health Check-up




          http://elearning.medicine.swu.ac.th/edu/
                    วัตถุประสงค์
•   เพื่อให้ ทราบความสาคัญของการตรวจคัดกรอง
•   เพื่อให้ ทราบการแปลผลเครื่องมือการตรวจคัดกรอง
•                                                      ้
    เพื่อให้ ร้ ูจักเลือกใช้ กระบวนการตรวจคัดกรองในการปองกันโรค
           Patient Profile I
• A 55-year-old high school teacher visited her
  physician at Mahachakri Sirindhron Medical Center
  for an annual checkup. She reported no illnesses
  during the preceding year, felt well, and had no
  complaints. The hot flashes she had experienced a
  year ago had cleared up without treatment. The
  physician performed a physical examination,
  comprising breast, pelvic (including Papanicolaou
  smear), and rectal examinations: all were
  unremarkable. Which diagnostic testing should be
  recommended for further checkup.
           Patient Profile II
• The results of the mammogram were not normal, and
  the radiologist suggested that a breast biopsy be
  performed. The patient was referred to a surgeon, who
  concurred that physical examination of the breast was
  normal. The surgeon and the radiologist agreed that
  fine needle aspiration of the abnormal breast under
  radiologic guidance was indicated. Evaluation of the
  specimen by a pathologist revealed cancer cells, and
  the patient was scheduled for further surgery the
  following week.
Screening and Diagnostic Test
Concepts:
• A screening test can be identified a disease
  before the time of routine diagnosis.
• Treatment at the time of detection by
  screening results in an improved chance of
  survival.
A comparison of a routine diagnosis and a diagnosis by screening


                                                     Diagnosis by symptoms

     Patient diagnosed from clinical symptoms        Apparent survival

 DNA      Cancer begins Cancer first     Lead time
 damage                 screen                                           Death
                        detectable

     Patient diagnosed by screening             Apparent survival

                                         Diagnosis by screening
Aims of Screening and Diagnostic Test

•   To determine the probability that disease present.
•   To assess the severity of an illness
•   To predict disease outcome
•   To monitor response to therapy
Criteria for a successful screening program

 • Morbidity / mortality are public concern
 • Early intervention reduce morbidity / mortality
 • A high-risk population must exist
 • The sensitivity and specificity acceptable
 • Minimal risk
 • Diagnostic workup acceptable morbidity
    Characteristics of tests
• Validity :
   – Sensitivity, Specificity
• Efficacy :
   – Predictive value
• Reliability :
   – Intra-subject variation, Inter-subject variation
     (Percent agreement, Kappa, ICC)
        Validity of the Test
Definition:
Sensitivity
 Probability that a test will be positive
 given a patient with disease

Specificity
 Probability that a test will be negative
 given a patient without disease
         Efficacy of the Test
Definition:
Positive Predictive Value (PPV)
  Probability that a patient will have a disease
  given a positive test result.
Negative Predictive Value (NPV)
  Probability that a patient will not have a disease
  given a negative test result.
        Validity and Efficacy of Test
Test results    With Disease       Without Disease           Total


Positive           True +              False +          All who test +


Negative           False -              True -          All who test -


Total          All with disease   All without disease
              Likelihood Ratio
• LR Positive
  ความน่าจะเป็ นที่จะได้ ผลTest positive ในคนที่เป็ นโรคเทียบกับ
  ความน่าจะเป็ นที่จะได้ ผล Test positive ในคนที่ไม่เป็ นโรค=
  Sensitivity / 1 - Specificity
• LR Negative
  ความน่าจะเป็ นที่จะได้ ผลTest negative ในคนที่เป็ นโรคเทียบกับ
  ความน่าจะเป็ นที่จะได้ ผล Test negative ในคนที่ไม่เป็ นโรค
      = 1 – Sensitivity / Specificity
                       Accuracy
• ความน่ าจะเป็ นที่จะได้ ผลทดสอบเป็ นจริงไม่ ว่าจะเป็ น True
  positive และ True negative

  = All with true result / All test done
  = Sensitivity X Prevalence + Specificity X (1-Prevalence)
           Multiple Tests
• Parallel test
• Serial test
                       ่
 Predictive value ใช้ คา Prevalence ที่เปลี่ยนไป
 เป็ น Pretest prevalence ของ test อันต่อมา

 Post-test odds of disease =
 Pre-test odds of disease X LR1 X LR2 X ...
                          Serial Test
ตัวอย่ าง
    นาย ก แพทย์ ประมาณว่ ามีโอกาสเป็ นโรค 60%
    ทา test 1 ที่มี sensitivity 70% และ specificity 80% ผล positive โอกาสเป็ นโรค
    เพิ่มเป็ น 84%
    ส่ งทา test 2 ซึ่งมี sensitivity 50% และ specificity 90% ผล positive โอกาสเป็ น
    โรคเพิ่มเป็ น 96%
วิธีทา      Pre-test odds of disease                = 0.6 / (1-0.6)        = 1.5
            LR + Test 1                             = 0.7 / (1-0.8)        = 3.5
            LR + Test 2                             = 0.5 / (1-0.9)        = 5.0
            Post-test odds of disease               = 1.5 x 3.5 x 5.0      = 26.25
            Positive predictive value               = 26.25 / (1+26.25)    = 96%
Prevalence and Predictive value
           Surgical Biopsy                       Surgical Biopsy
            Without mass                           With mass
          Cancer No Total                      Cancer    No     Total
 FNA+        14       8      22       FNA+       113     15     128

 FNA -        1      91      92       FNA -       8      181    189

 Total       15      99      114      Total      121     196    317
Result :                               Result :
Prevalence = 13%                       Prevalence = 38%
Sensitivity = 93% Specificity = 92%    Sensitivity = 93% Specificity = 92%
PPV         = 64% NPV         = 99%    PPV         = 88% NPV         = 96%
   Sensitivity / Specificity and Predictive value
                     Fix Prevalence 10% Population 100

Sensitivity Specificity   Test   Disease   No Dis.   Total    PPV     NPV
   50           50         +          5        45      50     10%
                           -          5        45      50             90%
                                     10        90     100
   90           50         +          9        45      54    16.7%
                           -          1        45      46            97.8%
                                     10        90     100
   50           90         +          5         9      14    35.7%
                           -          5        81      86            94.2%
                                     10        90     100
Cut off point of Continuous variables

• Receiver Operator Characteristic (ROC) Curve
              1
                      A
                          B


    Sensitivity
     (True +)




                  0                             1
                              1 – Specificity
                                 (False +)
              Reliability
Characteristic :
• Intra-subject variation
  – Blood pressure, Blood sugar
• Inter-observer variation
  – Ultrasound examination, Physical examination
                    Reliability
Measurement :
• Binary or Categorical measurement
  – Overall percent agreement
  – Kappa coefficient ( > 0.75 “ excellent agreement beyond chance ” )
    = Observed agreement(%) –Expected agreement(%)
                  100 – Expected agreement(%)
• Continuous measurement
  – Intraclass correlation coefficient (ICC)
    =               Between subject variability
     Between subject variability + Between test variability + Random error
Example of Reliability Measurement

        +      -     Total   • Percent agreement (I)
                                = 10+160 =    85%
                                   200
 +      10     20     30
        (3)   (27)           • Percent agreement (II)
                                =   10     = 25%
  -      10 160 170
                                    40
        (17) (153)
                             • Kappa = 85 – 78 = 0.32
Total   20    180    200
                                       100 - 78
Residence of cancer patients:
  Nation Cancer Institute




         ที่มา: สถาบันมะเร็งแห่งชาติ 2008
The most common cancer:
              Males




ที่มา: สถาบันมะเร็งแห่งชาติ 2008
The most common cancer:
            Females




 ที่มา: สถาบันมะเร็งแห่งชาติ 2008
 Number by age-group and gender of all cancer

                                                     Male      Female

          20

          15
Percent




          10

           5

           0
               0-4   5-9 10-14 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75+

                                                   Age-group (year)



                                                                                   ที่มา: สถาบันมะเร็งแห่งชาติ 2008
Number by age-group for female breast cancer


          25

          20

          15
Percent




          10

           5

           0
               20-24   25-29   30-34   35-39   40-44    45-49   50-54     55-59   60-64    65-69   70-74    75+

                                                       Age-group (year)



                                                                                          ที่มา: สถาบันมะเร็งแห่งชาติ 2008
               Number by age-group for cervical cancer


          25

          20

          15
Percent




          10

           5

           0
                25-29   30-34   35-39   40-44   45-49   50-54   55-59   60-64   65-69   70-74    75+

                                                  Age-group (year)



                                                                                ที่มา: สถาบันมะเร็งแห่งชาติ 2008
Number by age-group and gender of lung cancer

                                                        Male      Female

          25

          20

          15
Percent




          10

           5

           0
               20-24   25-29   30-34   35-39   40-44    45-49   50-54     55-59   60-64    65-69   70-74   75+

                                                       Age-group (year)



                                                                                          ที่มา: สถาบันมะเร็งแห่งชาติ 2008
Number by age-group and gender of hepatobiliary cancer

                                                       Male        Female

              25

              20

              15
    Percent




              10

               5

               0
                   25-29   30-34   35-39   40-44   45-49   50-54     55-59   60-64   65-69   70-74    75+

                                                     Age-group (year)



                                                                                     ที่มา: สถาบันมะเร็งแห่งชาติ 2008
Number by age-group and gender for colon and rectum cancer

                                                        Male        Female

               25

               20

               15
     Percent




               10

                5

                0
                    25-29   30-34   35-39   40-44   45-49   50-54     55-59   60-64   65-69   70-74    75+

                                                      Age-group (year)



                                                                                      ที่มา: สถาบันมะเร็งแห่งชาติ 2008
        Risk Factors of Cancers
• Alcohol use
• Smoking
• Low fruit and vegetable intake
• Indoor smoke from household use of solid fuels
• Urban air pollution
• Overweight and obesity
• Physical inactivity
• Contaminated injections in health care settings
• Unsafe sex
    Intervention for Controlling Cancers

Primary Prevention

• Immunization or treatment of infectious agents

        Human papilloma virus & Hepatitis B virus

• Tobacco and alcohol control programs

        Lung, Esophagus, Liver Cancer

• More fruits and vegetables, fewer harmful fats and processed foods
Intervention for Controlling Cancers

Secondary Prevention
  Early detection & Screening Test
       High-Risk people
       Cost-Effectiveness & Feasibility
                Age-specific cancer incidence
                Life expectancy and temporal trend
                Population age structure
                Availability, effectiveness, cost of treatment
                Cost of screening
       Type of Cancer
           Cancer Screening
         Test                   Target Groups
                          Sex      Age       Interval
Sigmoidoscopy            Both   50 +        1 year
Fecal Occult Blood       Both   50 +        1 year
Rectal Examination       Both   50 +        1 year
Ultrasound Liver & AFP   Both   B&C Carrier ½-1 year
Barium Swallow           Both   50 +        1 year
Chest X-Ray              Both   50 +        1 year
Gynecologic exam & Pap Female 30-65 or Sex 1 year
            Cancer Screening
          Test                       Target Groups
                             Sex          Age         Interval
Uterine Curettage           Female High-Risk        Menopause
Clinical Breast Exam.       Female 20-40, 40 +      1-2, 1 year
Mammography                 Female 35-40            Base line
                                     41-49, 50 +    1-2, 1 year
Self Breast Exam.           Female 20 +             1 month
General Physical Exam*      Both     20-39, 40 +    3, 1 year
*Include CA thyroid, testis, prostate, ovary, LN, oral, skin

				
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posted:6/18/2011
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