All human cells have some receptors present on their surface. Normal human breast cells respond to the female hormones i.e. estrogen & progesterone, therefore they carry estrogen (ER) and progesterone receptors (PR).
Like healthy breast cells, majority of the breast cancer cells also possess ER & PR receptors. Every breast cancer is different and knowing the fact whether the breast cancer is positive for ER, PR receptors, has an important bearing on the management of the patient’s disease. If a patient’s breast cancer shows these receptors, then they can be subjected to hormonal therapy, which can control the tumor growth by blocking these receptors.
Sometimes during the course of treatment, the breast cancer cells which are ER, PR positive initially can lose the receptors and become ER, PR negative and they stop responding hormonal therapy. Rarely, the opposite of this is true as well.
Considering this background, it is important that a lady knows how to interpret the hormone receptor status report & understand the implications in breast cancer management based on this report.
Most laboratories used a special method to stain these receptors known as IHC (immunohisto-chemistry). Each lab has their own way of analyzing these receptors, which is why I am covering the most commonly used methods:
- A percentage that tells you how many cells out of 100 stain positive for hormone receptors.You will see a number between 0% (none have receptors) and 100% (all have receptors).
- Allred score between 0 and 8. This system looks at what percentage of cells test positive for hormone receptors along with the intensity of staining. This information is then combined to score the sample on a scale from 0 to 8. The higher the score, the more receptors were found and the easier they were to see in the sample.
- Positive or negative report
Different labs have different cutoff points for calling the cancer either positive or negative. For example, if less than 10% of your cells — or fewer than 1 in 10 — stain positive, one lab might call this a negative result. Another lab might consider this positive, even though it is a low result. Some studies have shown that even cancers with low numbers of hormone receptors may respond to hormonal therapy. A score of “0” means that the patient is hormone receptor negative and will not benefit from hormonal therapy.
Some points to remember
Once the report is declared, your oncologist with discuss your hormone receptor report with you and these are some points, which will help you in understanding your report:
- ER+/PR+:Majority (65%) of the Breast cancers are ER, PR positive and these patients are candidates for hormonal therapy.
- ER positive but PR negative OR ER negative but PR positive:Around 10-13% patients fall in these two categories. Despite one of the receptors being negative, these patients are still candidates for hormonal therapy.
- ER-/PR-:Around 20% patients fall in this category and they are not considered to be candidates for hormonal therapy.
If your test result is positive for ER/ PR, you should discuss the role of hormonal therapy with your oncologists. Hormonal therapy helps in preventing the recurrence of disease in patients with localized breast cancer whereas it keeps the tumor growth under control in patients with metastatic breast carcinoma.
Consultant, Breast Onco-Surgeon