Cancer Biomarkers vs Cancer Screening Test
A common question Positive Bioscience (India) is asked “what is the difference between cancer biomarkers and cancer screening?” Here’s what you need to know.
Cancer biomarker testing is exclusively for cancer patients. Cancer biomarkers help to decide the course of treatment and are especially used for newly diagnosed patients. However, in many cases, markers can be also tested for advanced cases. These markers vary by cancer type.
In India, the NCCN guidelines are very popular and are often used for newly diagnosed cancer patients. NCCN recommends these cancer biomarkers for Non-Small Cell Lung cancer patients: EGFR, ALK, ROS1, MET, RET, HER2, BRAF, KRAS, and PD-L1. Each of the genes may correspond to one or more treatment options, which may overlap with other genes. For example, EGFR positive patients may use Gefitinib as a treatment option. Ovarian cancer markers include BRCA 1 and BRCA 2.
When you do biomarker testing you may typically test for somatic mutations and protein expressions.
What can biomarkers tell you?
Not always but many times testing biomarkers will let you answer these important questions:
- Prognostic: is this likely to develop into cancer?
- Diagnostic: what kind of cancer?
- Predictive: what is the optimal drug for my cancer?
- Pharmacodynamics: what is the optimal drug dose for me?
- Recurrence: will my cancer return?
Cancer Screening Test:
Cancer screening tests are used to determine the genetic risk of getting cancer and to plan preventative steps for individuals with increased risks. Angelina Jolie is perhaps the most famous case study for cancer screening. Genetic testing or cancer screening is especially recommended for families with a strong cancer history. Cancer screening can also be used to assist early detection of a cancer. A cancer patient may also undergo a cancer screening test to see if there is a specific mutation which other family members may have.
The most common cancer screening test is BRCA 1 and BRCA 2 but increasingly multi-gene panels, which include the BRCA genes are becoming popular in India. In breast cancer cases, BRCA testing is also used to help identify patients who are at high risk of cancer recurrence and to patients more likely to develop breast cancer in the other breast. Read our breast cancer guide.
When you do cancer screening tests you may typically test for germline mutations
Can Cancer Biomarkers and Cancer Screening Overlap:
In most cases, cancer biomarker testing is done on FFPE blocks, which is the cancer tumor biopsy. Cancer screening testing is normally done on blood although several labs also offer a saliva based test. The overlaps are very few. BRCA 1 and BRCA 2 do overlap, as they can be a cancer marker (for PARP inhibitors) and a cancer screening test. However, in most cases, the tests for cancer biomarkers and cancer screening are different.