Cancer Screening and Biases Overview

Questions and Answers

What is lead time bias?

Apparent increased survival due to earlier detection (correct)

Decreased survival due to delayed diagnosis

Bias introduced by treatment methods

None of the above

What is length time bias?

Detection of slower-growing cancers leading to apparent increase in survivor duration (correct)

Bias related to the length of treatment

Influence of lifestyle changes on cancer survival

None of the above

What is positive predictive value?

The proportion of patients who test positive that have the disease

What is negative predictive value?

The proportion of patients who test negative that do not have the disease Signup and view all the answers

What is sensitivity?

The ability to correctly identify those who do have the disease Signup and view all the answers

What is specificity?

The ability to correctly identify those who do not have the disease Signup and view all the answers

What is the single most important risk factor for developing breast cancer?

Age Signup and view all the answers

When does the American Cancer Society recommend starting breast cancer screening?

At age 40 Signup and view all the answers

What is the false negative rate of mammography?

10% Signup and view all the answers

When is MRI recommended for breast cancer screening?

In women ages 25-30 and older who have a known BRCA mutation or other specific risk factors Signup and view all the answers

When should screening colonoscopy begin for those with a family history of colorectal cancer?

At age 40, or 10 years earlier than the age at which a family member was diagnosed Signup and view all the answers

How often should a person with a normal colonoscopy be screened if they have a family member diagnosed with colorectal cancer at age less than 60?

Every 5 years Signup and view all the answers

How often to repeat colonoscopy if one has normal or hyperplastic polyps?

Every 7-10 years Signup and view all the answers

When should prostate cancer screening stop?

At age 75 or older Signup and view all the answers

What is PSA velocity?

The rate of increase of PSA values over time Signup and view all the answers

When should lung cancer screening be performed?

In current smokers or those who have quit within the past 15 years, aged 55-74 or 55-80 depending on recommendations Signup and view all the answers

When should early colon cancer screening be done?

If there is a first-degree relative with a history of colon cancer diagnosed at age less than 60 Signup and view all the answers

Study Notes

Study Notes on Cancer Screening and Biases

Lead Time Bias: Apparent increased survival attributed to earlier detection of a disease.
Length Time Bias: Occurs when slower-growing cancers are more likely to be detected through screening, creating a false impression of longer survival in screened populations.

Diagnostic Values

Positive Predictive Value: Percentage of patients who test positive and actually have the disease.
Negative Predictive Value: Percentage of patients who test negative and do not have the disease.
Sensitivity: Ability to accurately identify individuals who have the disease.
Specificity: Ability to accurately identify individuals who do not have the disease.

Breast Cancer Screening

Most Important Risk Factor: Age is the single most important risk factor for developing breast cancer.
- One first-degree relative with breast cancer doubles the risk; two or more quadruples it.
Screening Recommendations:
- Begin breast cancer screening at age 40, per the American Cancer Society and National Cancer Institute.
- American College of Physicians and U.S. Preventive Services Task Force recommend individualized discussions for women aged 40-49, without routine mammography recommendations for this age.
Mammography False Negative Rate: Approximately 10%. All palpable masses require further evaluation through ultrasound, even with an unremarkable mammogram.

MRI Recommendations for Breast Cancer

Conditions for MRI:
- Women aged 25-30 or older with a known BRCA mutation.
- First-degree relatives of individuals with a known BRCA mutation.
- Patients who underwent chest irradiation between ages 10-30.
- Individuals with over 20% lifetime breast cancer risk according to clinical risk predictions.

Colorectal Cancer Screening

Family History Guidelines:
- Initiate screening colonoscopy at age 40 if a first-degree relative was diagnosed with colorectal cancer before age 60, or 10 years earlier than the age of diagnosis in the family member.
Screening Intervals:
- For individuals with a first-degree relative diagnosed with colorectal cancer before age 60, repeat colonoscopy is every 5 years if initial screening is normal.
- If normal or hyperplastic polyps are found, repeat colonoscopy is recommended every 7-10 years.

Prostate Cancer Screening

Age to Stop Screening: Prostate cancer screening is typically discontinued for individuals over 75 years of age.
PSA and Biopsy Decision: Assess PSA velocity, particularly if the PSA value exceeds 4.0 ng/ml and increases by more than 1 ng/ml per year, suggesting the need for a prostate biopsy.

Lung Cancer Screening

Eligibility for Screening: Recommended for current or former smokers (quit within the last 15 years) aged 55-74 with a 30 pack-year smoking history (ACS guidelines) or aged 55-80 (USPSTF guidelines).

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Description

Explore key concepts in cancer screening, including lead time bias and length time bias. Learn about diagnostic values such as positive predictive value, sensitivity, and specificity. Understand the importance of age and familial risk factors in breast cancer screening.