You are here

Understanding Cancer Screening

  • 04.18.2015

Cancer Screening - Sierra Nevada Cancer Center


Cancer screening is the process of checking for conditions that may potentially lead to cancer. Benefits of screening include finding and possibly treating the cancer early, and the common belief is that treatment is more effective when found early. However, not all cancers have a screening test. Among those shown to be most successfully screened are cervical and colon cancer.

Cancer screening, like many medical processes, is still evolving and can be considered controversial—coming with its pros and cons. While the benefits of cancer screening are obvious—detecting cancers before they cause symptoms and potentially extending lives, the downsides are lesser known, but just as important to understand. We'll explore both sides in this newsletter and provide you with the resources you need to make an educated decision when it comes to your health.1


Detecting cancer early can save lives, but there can be harmful side effects to routine cancer screening. As with any test, it is possible to receive false positive, or negative, results. A false positive test result can lead to extreme anxiety and unnecessary follow-up procedures, while a false negative can lead to missing a cancer diagnosis.

Over diagnosis is also a possibility. With over diagnosis, a patient whose test results come back positive for a particular cancer receives invasive therapies such as chemotherapy or surgery. If the cancer is slow growing, it may not have harmed the patient at all during their natural lifespan if left untreated.1


It's always best to be informed when it comes to your health. What's the best way to learn about cancer screeningsNational Cancer Institute website recommends their Physician Data Query resource (PDQ) (, a guide for both patients and physicians that provides a description of different cancer screening tests, as well as the United States Preventive Services Task Force web-site ( which offers a wide range of prevention in screening tests.1

And of course, talk to your doctor about your questions and concerns.

Talk to your doctor about your questions and concerns - SNCC


Three questions to ask your doctor when deciding if cancer screening is right for you:

  • What Are My Chances of Dying if I Don't Get Screened? You will want to ask your doctor not only the odds of death if you choose to not get screened, but also, if you do decide to follow through with screening, will the change in the odds of dying be significant enough to warrant the screening.2
  • What Are the Relative Risks & Absolute Risks? These terms often come up when discussing cancer screening.  It's important that the difference between the two is clear and what each means. Often expressed as a percentage, absolute risk is the chance that a person will develop a disease during a given period of time. Relative risk compares the risk between a group of people who have a particular risk factor and those who don't.3
  • Is There Evidence This Screening Test Works? As a patient, you want to ensure there is demonstrative evidence that the chances of dying from a particular type of cancer are lower in those who are screened versus those who are not.2
Cancer Screening - Sierra Nevada Cancer Center
To Screen or Not to Screen
Patients often choose to screen after hearing both the risks and benefits because they want to feel that they are doing everything they can to lower their chance of dying from cancer. There are other patients who decide being healthy in the present is what's most important and the potential side aren't worth the risks.


There are two main types of cancer screening tests are:

  • Imaging Tests: Includes mammograms and computed tomography (CT) scan procedures. A mammogram is an x-ray picture of the breasts used to detect breast cancer. A CT scan, also known as the computerized axial tomography (CAT) scan, uses x-ray equipment to create a series of pictures on areas inside the body. It is often used to detect tumors.5
  • Laboratory Tests: A procedure in which a sample of bodily fluid or tissue is examined to get information about a patient's condition. Includes tests performed in a diagnostic laboratory setting such as a PAP, HPV, and Prostate-Specic Antigen (PSA) test..5


1 Screening and Testing to Detect Cancer, National Cancer Institute, Retrieved July 10, 2014,

2 Questions to Ask Your Doctor About Cancer Screening, National Cancer Institute, Retrieved Aug. 19, 201,

3 Understanding Cancer Risk, Cancer.Net, Retrieved July 10, 2014,

4 All that Glitters, A Glimpse Into the Future of Cancer Screening, National Cancer Institute, Retrieved Aug 29, 2015,

5 Types of Screening Tests, National Cancer Institute, Retrieved July 10, 2014,


Related articles