The differences among cancer cells (tumor heterogeneity) is why your pathology report, blood tests, and other tests can be so complicated and why there are so many different treatments for breast cancer. Because the cancer cells can be so different, what kills one type of cell might not do anything to another.
The best overall treatment involves getting the best out of each specialty. Surgery, radiation, chemotherapy, hormonal therapy, and targeted therapies all work in different ways on their own — plus they can be extra effective when given together.
More than one hundred medications have been approved to treat cancer, and many more are being developed. Some treatments are very specialized, designed to target only a particular gene or protein in the cancer cells. This targeted therapy might do its job well, but that's only one part of the overall fight against the cancer. Other treatments are needed to fight other targets in the cancer cells. Each treatment does its part to get rid of the whole cancer. This is why some treatments work best in combination with other treatments or before or after other therapies.
The differences in cancer cells are why two people with breast cancer may have completely different treatment plans. You may meet other people in the waiting room before your exams or therapies. It's quite common to share stories about diagnosis and treatment. Remember, though, that each cancer has a different personality and will have a different treatment plan. When you're talking to someone else, it's hard to know if her situation is similar to or different from yours. So you won't want to make decisions about your own treatment based on what someone else is doing. What's working for her may be different than what's working for you.
A more complete picture
Targeting specific characteristics of cancer cells, such as a protein that allows the cancer cells to grow in a rapid or abnormal way, has led to the development of a number of new treatments. For example:
- Hormonal therapy medicines target hormone receptors that cause cancer cell growth.
- HER2 inhibitors work against HER2-positive cancers by blocking the cancer cells’ ability to receive growth signals.
- CDK4/6 inhibitors work against metastatic breast cancers that are hormone-receptor-positive and HER2-negative by stopping the cancer cells from dividing and growing.
- PARP inhibitors work against metastatic HER2-negative breast cancer with a BRCA1 or BRCA2 mutation by making it difficult for cancer cells to fix DNA damage.
- PI3K inhibitors work against HER2-negative breast cancers with a PIK3CA mutation.
Researchers suspect that other specific genes in individual breast cancers can be identified. Once discovered, it’s possible that treatments can be developed to target those specific genes.
Genomic tests analyze certain genes in breast cancer cells. By measuring the activity levels of specific genes, these tests calculate a recurrence score. The higher the recurrence score, the more likely the cancer is to come back. Looking at the cancer's other characteristics AND genomic test results can help predict the risk of cancer coming back. This information can help women and their doctors decide other treatments after surgery would be beneficial.
Researchers hope to develop tests that can give us a fuller, more complete picture of a cancer tumor's genetic makeup. Then treatments can be prescribed that are personalized for each cancer.
For help understanding your diagnosis and treatment options, you can use My Breast Cancer Coach. My Breast Cancer Coach is a questionnaire designed to help you better understand your type of breast cancer so you can focus on the information that's most relevant to you.