CANCER SCREENING

Dr. Abhilash G

JR-1 Radiotherapy

SRMSIMS

WHAT IS SCREENING AND WHY DOES

IT NEED TO BE DONE?

Cancer screening aims to detect cancer

before symptoms appear.

This may involve blood tests, urine tests, other

tests, or medical imaging.

The benefits of screening in terms of cancer

prevention, early detection and subsequent

treatment must be weighed against any

harms.

Cancer screening is not indicated unless life

expectancy is greater than five years and the

benefit is uncertain over the age of 70.

Screening is not normally useful for rare

cancers.

Countries often focus their screening

recommendations on the major forms of

treatable cancer found in their population.

Screening recommendations depend on the

individual's risk, with high-risk people receiving

earlier and more frequent screening than low-

risk people.

ROAD MAP FOR DISCUSSION

I will continue my discussion under the

following headings

A. Breast Cancer Screening

B. Cervical Cancer Screening

C. Colorectal Cancer Screening

D. Genetic Screening

E. Lung Cancer Screening

F. Prostate Cancer Screening

G. Head and Neck Cancer Screening

A. BREAST CANCER

SCREENING

NCCN BREAST SCREENING CONSIDERATIONS

Screening Women at Average Risk

For women between ages 25-40 yrs CBE

recommended every 1 to 3 yrs and breast

awareness encouraged.

For women aged >40 yrs Annual CBE and

screening mammography and breast

awareness is encouraged.

Mammograms can often detect a lesion 2

yrs before the lesion is discovered by CBE.

Yearly screening is thought to be more

beneficial.

CONTD..

Screening Women At Increased Risk

Modified Gail Model assesses the risk of invasive breast cancer as a function of age, menarche, age at first live birth or nulliparity, number of first degree relatives with breast cancer, number of previously benign breast biopsies, atypical hyperplasia and race.

This model calculates and prints 5-year and lifetime projected probabilities of developing invasive breast cancer and identifies increased risk.

Gail model should not be used for women with gene mutation, strong family history, prior thoracic radiation or for those with LCIS.

CONTD..

For a woman aged 35 yrs or older with a 5-yr

risk > 1.7% and patients with LCIS, CBE

every 6 to 12 months and annual

mammography along with breast awareness

is encouraged.

For a woman with >20% lifetime risk of

breast cancer (based on family history),

breast awareness and beginning at 30, CBE

every 6 to 12 months and annual

mammography. Annual breast MRI is also

recommended

CONTD..

For a woman who is a carrier of BRCA 1/2

mutation, CBE every 6-12 mo starting at age

25, breast awareness, annual mammograms

and breast MRI as an adjunct.

MAMMOGRAPHIC SCREENING

A screening mammogram typically involves

two x-ray images of each breast, one

craniocaudal and other mediolateral oblique.

Mammography results are mandated to be

reported using BI-RADS developed by the

American College of Radiology.

BI-RADS – Breast Imaging Reporting and

Data System

BI-RADS CATEGORIES

Category 0 – Needs additional Imaging

and/or Prior Mammograms to compare

Category 1 – Negative

Category 2 – Benign findings

Category 3 – Probably Benign; Short Follow

up

Category 4 – Suspicious Abnormality; Biopsy

Category 5 – Highly S/o Malignancy

Category 6 – Known Biopsy Proven

BREAST MRI SCREENING

The sensitivity of breast MRI at detecting breast cancer is higher than the sensitivity of mammography, although the specificity of the former is lower.

NCCN recommends annual MRI as an adjunct in the following

1. Women with known genetic predisposition for HBOC starting at age 25.

2. Women with prior thoracic radiation between ages 10-30 yrs.

3. Women with >20% lifetime risk as described by ACS guidelines.

B. CERVICAL CANCER

SCREENING

Women should begin screening at 21yrs of

age, regardless of whether sexual

intercourse has already occurred.

Data indicate that cervical screening should

be avoided in women younger than 21yrs,

because these women are at very low risk of

cervical cancer and because treatment can

lead to complications.

CONTD..

After initiation, cervical screening should be

performed every 3 yrs in women 21-29 yrs of

age with cervical cytology alone. However,

women with high risk factors should receive

more frequent screening, usually annually.

Screening for women > 30 yrs include

1. Cervical cytology combined with DNA

testing for high risk HPV types every 5 yrs

(preferred)

2. Cervical cytology alone every 3 yrs.

Cervical cytology alone is more effective at detecting squamous cell carcinoma than adenocarcinoma. Co-testing is preferred because HPV DNA testing increases detection of adenocarcinoma and adenocarcinoma in situ.

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.

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 and after initial

postoperative surveillance, 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.

C. COLORECTAL CANCER

SCREENING

Screening Modalities that detect Adenomatous Polyps and 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)

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.

Individual risk factors and physician

judgment should be included.

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.

Performed using a scope 60cm or longer.

Patients with lesions larger than 1cm should directly be referred for colonoscopy since they are almost always adenomatous polyps.

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, which are present, pose a

dilemma.

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 collection or suboptimal processing.

These tests are recommended annually alone or in combination with flexible sigmoidoscopy every 5 years.

FECAL OCCULT BLOOD TEST

Two FOBT’s are available – Guaiac based and Immunochemical.

Guaiac FOBT

- MOA is based on the pseudoperoxidaseactivity 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 stool specimens.

FECAL OCCULT BLOOD TEST

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 screening tool.

D. GENETIC SCREENING

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.

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 1/2 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.

GENETIC TESTING

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.

E. LUNG CANCER

SCREENING

RISK ASSESSMENT

NCCN Screening Panel recommends lung

cancer screening using helical LDCT for

individuals with following high risk factors.

1. 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. >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.

CONTD..

NCCN defines moderate risk individuals as those aged 50 yrs or older and with a 20 or more pack-year history but no additional lung cancer risk factors.

NCCN defines low risk individuals as those younger than 50 yrs and/or with a smoking history of fewer than 20 pack-years.

It does not recommend screening for these individuals.

F. PROSTATE CANCER

SCREENING

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.

ACS advises that if PSA < 2.5ng/ml, retesting

may need to be done only every 2 yrs.

Men with > 2.5ng/ml should have annual testing.

In May 2013, the American Urological

Association (AUA) released new guidelines

supporting routine use of PSA in healthy men 55

to 69 yrs who are at average risk and are

asymptomatic.

AUA do not recommend testing in men <40 yrs,

40-54 yrs with average risk, >70 yr old males

nor in males with life expectancy less than 10-

15 yrs.

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 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.

THANK YOU