Aromatase Inhibitor Before Surgery May Make Lumpectomy an Option

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A study looked at whether an aromatase inhibitor taken before surgery could reduce the size of a hormone-receptor-positive, early-stage breast cancer so a woman could have lumpectomy rather than mastectomy. Results showed that about two-thirds of the women for whom mastectomy was recommended were candidates for lumpectomy after taking an aromatase inhibitor. These research findings were presented at the 2010 American Society of Clinical Oncology (ASCO) Breast Cancer Symposium.

Aromatase inhibitors are a type of hormonal therapy medicine. Many postmenopausal women take hormonal therapy medicine -- either an aromatase inhibitor or tamoxifen -- AFTER surgery and other treatments for hormone-receptor-positive, early-stage breast cancer. Hormonal therapy can reduce the risk of the cancer coming back (recurrence). Hormonal therapy taken after surgery is called adjuvant hormonal therapy.

The aromatase inhibitors are:

  • Arimidex (chemical name: anastrozole)
  • Aromasin (chemical name: exemestane)
  • Femara (chemical name: letrozole)

Doctors call treatments given BEFORE surgery neoadjuvant treatments. So hormonal therapy taken BEFORE surgery is called neoadjuvant hormonal therapy. The goal of neoadjuvant treatments are to weaken the breast cancer and reduce its size and spread before surgery.

In this study, 374 women were diagnosed with estrogen-receptor-positive breast cancer that was considered to be very sensitive to estrogen, based on high Allred scores.

The Allred score -- which is sometimes listed in the pathology report -- rates breast cancers based on the proportion of cells in the tumor sample that have estrogen receptors (called the proportion score) as well as how many receptors individual cells have (called the intensity score). The Allred score combines the proportion score and the intensity score and can range from 0 to 8. The higher the score, the more sensitive to estrogen the cancer is considered. The cancers in this study had Allred scores ranging from 6 to 8.

The researchers noted the type of surgery recommended for each woman before any neoadjuvant hormonal therapy was given. The surgery recommendations were based on tumor size, using the TNM staging system:

  • Lumpectomy was recommended for tumors 5 cm or smaller (T1 or T2).
  • Mastectomy was recommended for tumors larger than 5 cm (T3).
  • Mastectomy also was recommended for any size tumor that had spread to the chest wall or skin (T4).

After neoadjuvant hormonal therapy, women diagnosed with cancers that shrank from T3 to T2 or T1 would now be recommended to have lumpectomy instead of mastectomy. Women diagnosed with T4 cancers would still be recommended to have mastectomy after neoadjuvant hormonal therapy no matter how the cancer responded to the treatment.

The women in the study took one of the aromatase inhibitors for 16 weeks. After the 16 weeks of treatment, the researchers evaluated the cancer's response (called clinical response) and whether the recommended surgery changed from mastectomy to lumpectomy.

The cancers' response to the neoadjuvant hormonal therapy depended on which aromatase inhibitor a woman took:

  • 60% of women taking Aromasin had some response
  • 68% of women taking Arimidex had some response
  • 72% of women taking Femara had some response

Most of the women with cancers initially staged T3 had enough response to the neoadjuvant hormonal therapy so the recommended surgery changed from mastectomy to lumpectomy. This happened with:

  • 77% of women taking Femara
  • 85% of women taking Aromasin
  • 86% of women taking Arimidex

Not all of the women who had their recommended surgery change from mastectomy to lumpectomy chose to have lumpectomy. Still, after taking neoadjuvant hormonal therapy for 16 weeks, 81 of 159 eligible women chose lumpectomy.

Right now, neoadjuvant chemotherapy is more common than neoadjuvant hormonal therapy to weaken and shrink breast cancers before surgery. This study suggests that neoadjuvant hormonal therapy could be a good option for some women and may allow many of them to choose lumpectomy instead of mastectomy. Still, more research is needed. Researchers are now comparing the effectiveness of neoadjuvant hormonal therapy to neoadjuvant chemotherapy.

If you've been diagnosed with hormone-receptor-positive, early-stage breast cancer, you may want to ask your doctor if neoadjuvant treatment makes sense for you. Together, you and your doctor will consider all the details of your unique situation and develop the best treatment plan for you.

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