Transcript Screening programme for cancers

Screening programme for
cancers
CL Teng
[email protected]
Level of prevention
o
1
o
2
Age-specific cancer incidence,
per 100,000 population
Age-specific cancer incidence by
ethnicity and sex, West Malaysia 2003
Sex-race specific
cancer incidence
1600
1400
M-M 90.1
M-C 181.8
M-I 130.7
F-M 102.9
F-C 206.5
F-I 188.3
1200
1000
800
600
400
200
0
0-9
10-19 20-29 30-39 40-49 50-59 60-69
70+
Age groups, year
GCC Lim, Y Halimah (Eds). Second Report of the National Cancer Registry. Cancer
Incidence in Malaysia 2003. National Cancer Registry. Kuala Lumpur 2004.
http://www.acrm.org.my/ncr/documents/NCR_2nd_Report/Full_report.pdf
Age-specific cervical cancer
incidence, per 100,000
population
Age-specific cervical cancer incidence by
ethnicity and sex, West Malaysia 2003
140
Race specific
cancer incidence
120
100
M 10.5
C 28.8
I 22.4
80
60
40
20
0
0-9
10-19 20-29 30-39 40-49 50-59 60-69
70+
Age groups, year
GCC Lim, Y Halimah (Eds). Second Report of the National Cancer Registry. Cancer
Incidence in Malaysia 2003. National Cancer Registry. Kuala Lumpur 2004.
http://www.acrm.org.my/ncr/documents/NCR_2nd_Report/Full_report.pdf
Ten most frequent cancers in males,
Peninsular Malaysia 2003
Lung cancer
Collapse of the left upper lobe with elevation of the left main bronchus with
cutoff of the upper lobe bronchus. Left upper lobe mass at the left hilum.
http://www.imagingpathways.health.wa.gov.au/includes/image/nspul_c/XR.JPG
Lung cancer screening
Detect mass if >2cm
Sputum cytology
CXR  sputum cytology 6-monthly
vs
CXR annually or at the end of 3-year follow-up.
Screening detect more lung cancer cases but no difference
in survival in the two groups.
Five RCTs:
USPSTF 2004: Do not recommend for or against
Lung cancer screening
Low dose Computerised Tomography
(LDCT)
13 observational studies (mostly cohort studies [CS). No RCT.
LDCT detects 3x more lung cancers than CXR (and smaller cancers).
In one study, LDCT detected 23% of nodules (compared to 7% by CXR)
but only 3% of the nodules were cancers (low PPV).
USPSTF 2004: Do not recommend for or against
Colon cancer
There is a well-described sequence of mutational events that characterize the
transition from normal colon epithelium to premalignant adenoma and then
invasive adenocarcinoma.
http://www.nature.com/nrc/journal/v3/n8/fig_tab/nrc1147_F1.html
Colorectal cancer screening
Faecal occult blood test (FOBT)
Double contrast barium enema
Sigmoidoscopy/colonoscopy
CT colography (virtual colonoscopy)
Colorectal cancer screening
• Average risk: Age  50 (M&F), FOBT
(yearly), flexible sigmoidoscopy (5 yearly),
colonoscopy (10 yearly) or barium enema
(5 yearly)
• High risk: First-degree relative with ca
colon. Start screening from age  40
USPSTF, see Ann Intern Med 2002;137:129-31
Incidence of colorectal cancer in Asian
vs US and UK populations (1993–97)
Sung JJ, et al. Increasing incidence of colorectal cancer in Asia: implications for
screening. Lancet Oncol 2005; 6(11):871-876
“Although changes in dietary habits and lifestyle are
believed to be the reasons underlying the increase,
the interaction between these factors and genetic
characteristics of the Asian populations might also
have a pivotal role.”
Sung JJ, et al. Increasing incidence of colorectal cancer in Asia: implications for
screening. Lancet Oncol 2005; 6(11):871-876
Prostate cancer screening
• Insufficient evidence to recommend for or
against screening for prostate cancer
using PSA (prostate-specific antigen) or
DRE (digital rectal examination).
• PSA detects early-stage cancer but
improvement in health outcomes is mixed.
• Screening is associated with frequent
false-positive result and unnecessary
anxiety.
Prostate cancer
Prostate cancer screening
• Current evidence is insufficient to
assess the balance of benefits and harms
of screening for prostate cancer in men
younger than age 75 years (I statement).
• Do not screen for prostate cancer in men
age 75 years or older (Grade D
recommendation)
USPSTF, see Ann Intern Med 2008;149(3):185-91
Prostate cancer
• USA: most men over the age of 50 years
have had a PSA test, despite the absence
of evidence from large, randomized trials
of a net benefit. Moreover, about 95% of
male urologists and 78% of primary care
physicians who are 50 years of age or
older report that they have had a PSA test
themselves, a finding that suggests they
are practicing what they preach.
http://content.nejm.org/cgi/content/full/360/13/1351
Hepatocellular carcinoma
Hepatocellular carcinoma
• Inadequate evidence on screening with alphafetoprotein and/or ultrasound of the liver for patients
with chronic hepatitis B
• Only 2 RCTs.
– 1. Bi-annual screening with alpha-fetoprotein plus ultrasound vs
no screening for five years. More liver cancers were detected in
the screened group, but the two groups did not differ significantly
regarding liver cancer mortality.
– 2. Alpha-fetoprotein plus ultrasound screening vs alphafetoprotein screening. This trial, with an inadequate sample size,
showed no significant difference between the groups regarding
number of cancers detected.
http://www.cochrane.org/reviews/en/ab002799.html
Hepatocellular carcinoma
• Patients with chronic hepatitis B and C
infection especially those who are > 45
years of age, who have concomitant
cirrhosis or have a family history of HCC
should be examined every 3-6 months
with periodic serum alpha-fetoprotein
(AFP) measurements and abdominal
ultrasound examinations.
•Merican I. Screening for hepatocellular carcinoma. Med J Malaysia. 1996;51(1):12-7
Ten most frequent cancers in
females, Peninsular Malaysia 2003
BSE, CBE, Mammography?
Breast cancer screening
• Average risk: Age 50-69, 1-2 yearly
mammography.
– CBE: Do not recommend for or against.
– BSE: Do not recommend for or against.
Increased risk of false positive results and
biopsy.
• High risk: Mother/sister had ca breast.
Start screening from age  40
USPSTF, see Ann Intern Med 2002;137:344-6
Anderson BO, et al. Breast cancer in limited-resource countries:
health care systems and public policy. Breast J 2006; 12 Suppl 1:S54-S69
Modifying factors impacting on cervical
neoplasia and persistence of HPV infection
ASCUS: atypical squamous cells
of undetermined significance
Moore MA, Tajima K. Cervical cancer in the Asian Pacific - epidemiology, screening
and treatment. Asian Pac J Cancer Prev 2004; 5(4):349-361.
Cervical cancer screening
• In Malaysia, all women who are, or who
have been sexually active, age 20-65
years, are recommended to undergo Pap
smear testing.
• If the first two consecutive Pap results are
negative, screening every three years is
recommended.
MOH AMM CPG. Management of cervical cancer. 2003
Pap smear coverage
• 1993 to 2003, a total of 3,329,388 pap
smears were done
• Peak age of the women who had the pap
smears: 30-39 years.
• Peak age of cervical cancer: 60-69 years.
– Pap smear coverage: 0.8 to 2.9%.
• Pap smear screening in the country is not
strategic.
•Nor Hayati O, et al. Malaysian Journal of Medical Sciences. 2006;13(Suppl 1):113.
Screening criteria
1. Disease.
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•
Sufficient burden of suffering.
Detectable preclinical phase.
2. Test.
•
•
“Sensitive enough”.
“Specific enough” (to reduce FP).
3. Test, workup and treatment available.
4. Benefits outweigh harms
•
•
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Screened cases live longer.
Harms of overtreatment acceptable.
Cost of screening and treatment affordable.
The following statement(s) is/are correct
regarding cancer screening tests
A. False positive is a major concern with many
cancer screening tests.
B. Low-dose computerized tomography detects
lung cancer earlier and also prolong life of the
screened cases.
C. Mammography’s benefit is outweighed by its
harm in women above fifty years of age.
D. Alpha-fetoprotein is a good screening test for
hepatocellular carcinoma.
E. Regular colonoscopy is a useful screening test
for the detection of colorectal carcinoma.
Answer: T, F, F, F, T
The strongest proof that a cancer screening
programme is useful is that
A. Screening detects cancer earlier than
usual.
B. A cheap screening test is available.
C. Patients are very keen for this screening
programme.
D. Screened cases live longer.
E. Screening test is non-invasive.
Answer: D