Timing of Hormonal Therapy with Other Treatments

You and your doctor will have many discussions about the best treatments for YOU. You will discuss whether hormonal therapy should come after, before, or during other treatments.

Hormonal therapy after other treatments

The order of treatments is usually surgery first, chemotherapy second, radiation third, and hormonal therapy fourth. If you'll be treated with Herceptin (chemical name: trastuzumab), you might be given it before, during, or after other treatments, depending on your unique situation. Taking hormonal therapy after the other therapies ensures that you won't have too many side effects at once. Also, if you do have side effects during treatment, you'll have a better idea of what's causing them if you're only doing one treatment at a time.

There is also a concern that getting hormonal therapy at the same time as chemotherapy or radiation might make the treatments less effective. Here's why.

The goal of chemotherapy and radiation is to get rid of any cancer cells that might be left behind after surgery. Cancer cells are most likely to die from chemotherapy and radiation when they are actively growing. But hormonal therapy makes hormone-receptor-positive breast cancer cells STOP growing. So if you take hormonal therapy at the same time as your other treatments, and the cancer cells stop growing, maybe they won't respond as well to chemotherapy and radiation.

So far, studies suggest that it doesn't matter whether you take tamoxifen during or after radiation. The timing doesn't seem to affect recurrence, overall survival, or treatment side effects. However, another study found that women were more likely to be free of breast cancer and survive longer if they took chemotherapy followed by tamoxifen rather than if they took both therapies at the same time.

There's usually no rush to start hormonal therapy. Since you will be taking this therapy for five years and sometimes longer, delaying its start by several weeks is no big deal. Depending on your situation, your doctor may recommend that you start your hormonal therapy sooner or later.

For example, if you have aggressive disease, your doctor may want you to start your hormonal therapy right after chemotherapy, and continue it during radiation. If you have a breast cancer that is considered not very aggressive, your doctor might agree with your request to postpone the start of hormonal therapy for a few weeks to a few months.

Hormonal therapy before other treatments

Hormonal therapy might be recommended before any other treatments to shrink down a medium-to-large cancer before surgery. For example, if you have a hormone-receptor-positive breast cancer that is larger than two centimeters (about an inch), your doctor may suggest shrinking the tumor before surgery by using hormonal therapy for a few months. This way, it may be possible to have breast-conserving surgery—a lumpectomy and radiation—instead of a mastectomy. In one clinical trial, 46% of women who took Arimidex before surgery did not require a mastectomy, as opposed to 22% of those who took tamoxifen and 26% of those who took both treatments.

Hormonal therapy at the same time as other treatments

Sometimes, especially if the type of cancer you have is large or aggressive, your doctor may want you to take hormonal therapy at the same time as radiation treatment (which is a local treatment, targeted to a specific area). The hormonal therapy continues to provide a full-scale, whole-body attack for several months on any cancers cells that may be left behind after surgery.

In some situations, you may start hormonal therapy even if it's been a year or more since your main cancer treatment (surgery, radiation, chemotherapy) ended. You may also start hormonal therapy during ongoing Herceptin therapy.

Some women might not find out about the role of hormonal therapy until months after their other treatment. Other women may need more time to make a decision about taking hormonal therapy. And sometimes, other medical problems get in the way and can delay the start of hormonal therapy. Unlike other forms of treatment such as chemotherapy and radiation, which have to be started fairly quickly, hormonal therapy may provide benefits whenever it is started.