You may consider screening for a certain type of cancer. Screening is an attempt to detect cancer at an early stage, before clinical symptoms are present. In this stage, the cancer can be treated more successfully. When considering screening, the following questions can play a role: What is the risk that I will get this type of cancer? What is the probability of an incorrect screening result? What are the side effects of the test? Am I not too young to be screened? What is the chance that the cancer can be cured if it is found early? What would it mean for my family if it will be discovered that I have the gene indicating an increased risk of cancer?
The decision aids below can help you to find answers to the aforementioned questions, for example, about screening for the following diseases:
- Breast cancer. Screening for breast cancer is usually done with an X-ray picture of the breasts ('mammogram'). If there is any doubt about the results, the mammography can be repeated or you can have an ultrasound scan or a MRI.
- Genetic predisposition for breast cancer. Screening for this can be indicated if others in your family are diagnosed with breast cancer or if some family members are diagnosed at a young age. In these cases, you can have a genetic test on the breast cancer gene (BRCA1 or BRCA2) if you want.
- Cervical cancer. Screening for cervical cancer is usually done with a pap smear.
- Colorectal cancer (colon cancer, bowel cancer). Screening for colorectal cancer is most often done by FOBT (fecal occult blood test). This method tests if blood is present in the stool.
- Prostate cancer. Screening for prostate cancer is usually done by measurement of the PSA (prostate specific antigen) blood level. If the PSA level is higher than normal, a prostate biopsy can be executed.
Pros and cons of screening
Cancer screening tests are done to select participants who have a higher risk of cancer. Additional tests are necessary to find out whether cancer is present at all. Therefore, screening tests may be false-positive, suggesting you are at a high risk for having cancer while you do not actually have it. In this case, you and your family may worry needlessly. Besides, some of these additional tests may have risks. On the other hand, even if the screening result is reassuring, there is still a small chance that you have cancer and that the test was wrong ('false reassurance', also called 'false-negative' result).
It is also often the case that more persons will be diagnosed and treated for cancer, than would be the case if screening was not done. This is because some tumours may grow slowly and never cause any symptoms, because death may arise from other causes. However, it can be hard to predict whether a slowly growing tumour will cause symptoms in the future. In conclusion, if you get screened for cancer, you might get treated while this is not necessary, due to so-called 'overdetection'.
Cancer screening decision aids
The choice if you want to be screened can be a difficult one. Therefore, you can find decision aids below, which provide more information on the pros and cons of cancer screening for the mentioned types of cancer. Please discuss the decision aids with your doctor before making your final choice.