In this page I am giving short descriptions of tests used to diagnose, treat, and monitor breast cancer. I will start with tests that ARE NOT standard (everyone can find plenty of information about the standard)
1. TIL
TIL – tumor infiltrating lymphocytes. Cancer cell clusters are surrounded by white blood cells. These white cells are the ones trying to fight cancer. Immunotherapy teaches these cells how/where to fight. The more of them are present the better. This can be looked at by counting these cells on the biopsy
2. CT-DNA
CT-DNA is a useful test that allows to see if pieces of tumor DNA (genetic information) can be identified in blood. It is more accurate way to predict metastases since the standard test (PET scan) does not pick up anything that is smaller than 5 mm (roughly 1/5 of one inch). It is best to have the test at point 0 – before any treatment (first test needs the whole biopsy sample and a blood sample) and then monitor progress of therapy at various points determined by the team (3,6,9 weeks or 4,8,12 weeks depending on treatment plan and regimen) as well as periodically for surveillance. This test may or many not be covered by insurance and is done by Natera laboratory
3. Liquid Biopsy (North Star)
Liquid biopsy is a more sensitive test to look for residual cancer DNA. It analyzes more sequences and is more precise.
4. Imaging
Several imaging modalities are used in cancer diagnosis and monitoring:
- Tomocynthesis/mammogram (main screening and diagnostic tool) – images are taken from multiple angles and can detect presence of calcifications and asymmetry – those feature point to the need of further evaluation
- Ultrasound – safe, painless, no radiation. It detects masses. It is also used to perform biopsy more precisely and monitor progress. In those who undergo breast conservation surgery ultrasound is always used for monitoring and follow up
- PET scan – type of CT that is done with use of radioactive glucose to detect metastases and monitor
- MRI of the breasts is done to obtain more information about size, presence or absence of lymph nodes and geography of the breast in order to plan surgery
5. Signatera
Sinatera is one of available MRD (minimal residual disease) tests. It is not the most sensitive but very reasonable. MRD tests are probably the future of oncology. They are personalized assays based on DNA of the cancer (from the tissues). The test then looks for DNA presence in blood. It allows predicting recurrence way before it can be picked up by any imaging and is safe and painless way of monitoring cancer relapse. In case of that happening Signatera/Altera can see what would be the best predicted response to therapy