cancer, screening,introduction, methodology, cervix, breast, colorectal, prostate, lung, indian scenario

1. Cancer Screening
Presenter: Dr. Gaurav Kumar

2. Definition:
Secondary prevention method in which earlier therapeutic
intervention is possible through screening an asymptomatic
population to identify cancer at an earlier stage than it would have
been diagnosed in absence of screening .
 Primary prevention: Finding and removing adenoma thus reducing Colorectal cancer
burden
Goal:
To reduce mortality and/or severity of the disease through early
detection and treatment.

3. Principles of screening
● Disease should be important health problem in terms of frequency
and/or severity.
● Natural history of disease presents window of opportunity for early
detection.
● Effective treatment should be available that favorably alters natural
history of disease.
● Treatment should be more effective if initiated earlier than during the
symptomatic stage.
● Suitable screening test should be available.
● Appropriate screening strategy for the target population (i.e. age to
begin and screening interval)

4. Ideal screening test
• Cheap
• Sensitive
• Specific
• Accessible
• Safe
• Acceptable
Biases in screening
Lead time bias: (DPCP- Frequency of screening less than DPCP)
Length-bias sampling : Slow growing (less aggressive) tumors
vs fast growing (more aggressive) tumors.
Selection bias: Participation in screening by different
individuals.

5. Pitfalls of screening
● False-positive test result:
Lead to anxiety and unnecessary invasive diagnostic
procedures.
● Over diagnosis:
Diagnosis of a condition that would not have become clinically
significant had it not been detected by screening.
● False-negative test result:
Falsely reassure an individual with subsequent clinical signs or
symptoms of cancer and thereby actually delay diagnosis and
effective treatment.

6. ROAD MAP FOR DISCUSSION
A. Breast Cancer
B. Cervical Cancer
C. Colorectal Cancer
D. Lung Cancer
E. Prostate Cancer
F. Genetic Screening
G. Indian Scenario

7. NCCN
BREAST CANCER
SCREENING

8. Women at Average Risk
Age 20-40 yrs:
CBE every 1-3 yrs.
Age ≥ 40 yrs:
Annual CBE + Annual screening mammography.
Mammograms can often detect a lesion 2 yrs before the lesion is
discovered by CBE.
Yearly screening is thought to be more beneficial.
* Breast awareness is encouraged in all.

9. 5-yr risk > 1.7% (Gail‘s model):
Start screening at 35 yrs
CBE every 6-12 months + Annual mammography.
>20% lifetime risk of breast cancer (family history model):
Start screening at 30 yrs
CBE every 6-12 months + Annual mammography.
Carrier of BRCA 1/2 :
Start screening at 25 yrs
CBE every 6-12 mo
Annual mammograms and Breast MRI as an adjunct.
* Breast awareness is encouraged in all.
Women At Increased Risk:

10. Algorithm for palpable mass at
screening
Palpable mass
Age<30
Age≥30
Ultrasound
Mammogram
BI-RADS 1-3
BI-RADS 4-5
Tissue
Biopsy
BI-RADS 1-3
BI-RADS 4-5

12. NCCN
CERVICAL CANCER
SCREENING

13. ● Cervical cytology alone is more
effective at detecting squamous cell
carcinoma.
● Co-testing is preferred because HPV
DNA testing increases detection of
adenocarcinoma.
● The screening intervals should not be
increased in women 21-65 yrs with
negative tests.
● Use of HPV DNA testing alone for
screening is not currently
recommended.

14. ● Cervical cytology screening should be initiated and should be CONTINUED in
women who have been vaccinated against HPV 16 and 18.
● Women previously treated for CIN 2, CIN 3 should CONTINUE to have routine
screening for at least 20 yrs after treatment, because they remain at risk for
persistent or recurrent disease.
● Screening can be discontinued after total hysterectomy for benign disease.
● Screening may be discontinued for women with an intact cervix who are older
than 65 yrs with negative previous results and with no history of abnormal
cervical cytology tests.
● Women with co morbid or life threatening illness may discontinue screening.

15. ASC-US
LSIL/HSIL/ASC-H
AIS
AGC
HPV-DNA testing
Or
Repeat Cytology at 6 months
Or
Immediate Colposcopy
Negative
Positive
Colposcopy
Colposcopy + Endometrial Biopsy
Routine
screening
Algorithm for suspicious finding at
screening

16. Management according to
Colposcopic Biopsy finding
Colposcopy
Lesion seen
&Biopsy positive
Lesion not seen
& Biopsy Negative
Repeat pap/cytology at 6 mo
&
HPV DNA at 12 mo
CIN 1/CIN 2 CIN 3 AIS
CKC/LEEP
CKC/LEEP/Hysterectomy
CKC
Invasive Ca
Treat according to stage

17. NCCN
COLORECTAL CANCER
SCREENING

18. ● Screening Modalities that detect Adenomatous polyps
& Cancer
- Colonoscopy every 10 yrs
- Flexible Sigmoidoscopy every 5 yrs
- CT colonography (CTC) every 5 yrs
● Screening modalities that primarily detect cancer
- Guaiac-based screening
- Immunochemical based testing annually
- Stool DNA test with high sensitivity ( interval for screening is
uncertain)

19. COLONOSCOPY
● A 10 yr interval is appropriate for average risk patients who had an
optimal procedure.
● Shorter intervals may be indicated based on the quality and
completeness of the colonoscopy.
● Colonoscopy has limitations and cannot detect all cancers and
polyps.
FLEXIBLE SIGMOIDOSCOPY
● May be performed alone or in combination with stool based
screening.
● Requires no sedation unlike colonoscopy and less bowel
preparation, but is limited to examination of the lower half of the
colon tract.
● Patients with lesions larger than 1cm should directly be referred for
colonoscopy since they are almost always adenomatous polyps.

20. COMPUTED TOMOGRAPHIC COLONOGRAPHY
● Also known as Virtual colonoscopy or CTC.
● Advantage of being noninvasive and not requiring sedation.
However,a positive finding requires colonoscopy and extra
colonic findings.
● Overall data suggests that CTC may be useful for the detection of
larger polyps however, it is still an evolving technology.
FECAL BASED SCREENING TESTS
● Fecal tests are designed to detect signs of CRC in stool samples,
specifically occult blood or more recently alterations in exfoliated
DNA.
● They are noninvasive and no bowel clearance is necessary.
● However, they are less likely to detect adenomatous polyps.
● Sensitivity can be limited by inadequate specimen or processing.
● These tests are recommended annually alone or in combination
with flexible sigmoidoscopy every 5 years.

21. ● Two FOBT’s are available – Guaiac based & Immunochemical.
● Guaiac FOBT
- MOA is based on the pseudoperoxidase activity of heme in blood.
- It is the MC stool test in use for CRC screening.
- Major disadvantage is that it may miss tumors that bleed in small
amounts, intermittently or not at all and high false positive rate
- It should be performed on three successive
● Fecal Immunochemical Test
- Directly detects human globin within Hb.
- Does not require dietary restrictions and single sample is sufficient.
- It is more sensitive than guaiac FOBT.
● Stool DNA Test
- Emerging screening tool; detects the presence of known DNA
alterations.
- Not yet been approved by FDA and not considered a first line tool.
FECAL BASED SCREENING TESTS cont.

22. NCCN
LUNG CANCER
SCREENING

23. RISK ASSESSMENT
● NCCN Screening Panel recommends lung cancer screening
using helical LDCT for individuals with following high risk factors.
1. Age 55-74 yrs : 30 or more pack year history and if former smoker,
have quit within 15 yrs.
Annual screening recommended every 2 yrs.
2. Age < 50 yrs : 20 or more pack year history and additional risk
factors.
● NCCN Panel does not currently believe that exposure to second
hand smoke is an independent risk factor because the data is
weak.

24. CONTD..
● Moderate risk individuals: Age ≥ 50 yrs with ≥ 20 pack-year history
but no additional lung cancer risk factors.
● Low risk individuals: Age < 50 yrs and/or with a smoking
history of fewer than 20 pack-years.
● It does not recommend screening for these individuals.

25. NCCN
PROSTATE CANCER
SCREENING

26. Methods & Guidelines:
● DRE and PSA are the two components used in Prostate Screening.
● TRUS has been associated with a high false positive rate, making it
unsuitable as a screening tool.
● In 2010, ACS recommended that men make an informed decision about
whether to be screened for prostate cancer.
● If screening is done, it should begin at age 50 in men at average risk who
have a life expectancy of at least 10 yrs.

27. GENETIC SCREENING

28. ASCO GENETIC TESTING GUIDELINES 2010
● Genetic testing is recommended when there is….
1. Personal or family history suggesting genetic cancer
susceptibility.
2. The test can be adequately interpreted.
3. The results will aid in the diagnosis or influence the
medical or surgical management of the patient or family
members at hereditary risk of cancer.

29. RECOMMENDATIONS FOR HBOC
● Considerable initial screening is a reflection of the early age of
onset seen in HBOC.
● Women who is a carrier of BRCA ½ mutation, training in breast
awareness with regular monthly practice should begin at age 25.
● The woman should have annual mammograms and breast MRI
screening beginning at 25.
● Studies show that MRI is more sensitive than Mammography but
the downside is higher false positive result and higher cost relative
to mammography.

31. GENETICS AND COLORECTAL CANCER
● Management of individuals with a family history of FAP depends on
whether the familial mutation is known or unknown.
● Genetic testing of APC and/or MUTYH is important to differentiate
FAP from MAP and colonic polyposis of unknown etiology.
● When a patient with no familial mutation presents with h/o >10
adenomas, then comprehensive genetic testing of APC and/or
MUTYH is recommended.
● MUTYH testing can be performed prior to APC testing if a recessive
pattern is apparent in the pedigree.
● Genetic counseling and testing is recommended for patients with
multiple adenomatous polyps.

32. US Preventive Services Task Force
Ratings
Rating Interpretation for screening
A Strongly recommends
B Recommends
C No recommendation for or against
D Recommends against
I Evidence insufficient to recommend for or against
Cancer site USPSTF Rating
Oral cavity I
Skin I
Lung I
Breast B (Mammo + CBE)
I (CBE/BSE alone)
Colorectal A (FOBT)
B (Sigmoidoscopy ± FOBT)
Ovary D
Prostate I
Testis D

33. Cancer burden: India(GLOBOCAN 2012)

34. Current state of Cancer screening: India

35. Out of 809 women eligible for screening only 6.9% underwent screening
Total n =21015; Eligible women – 4009
Compliance rate: Breast 85%; Cervix 70%; Oral cavity 88%
Screening positivity rate: Breast 3.9%, Cervix 14.9%, Oral cavity 3.9%

36. SUMMARY
● Cancer screening is looking for cancer before a person has any
symptoms.
● False positive and false negative tests are possible.
● Finding the cancer may or may not improve the person’s health
or help the person live longer.
● Screening studies are done to see whether deaths from cancer
decrease when people are screened.
● Screening in India: Still at its infancy.
● We need strong political will/funds & infrastructure/trained
manpower and above all awareness of disease in general
population to make screening programme a success in our
country.

37. Thank You