• Breast Cancer Disease Site Group. The role of aromatase inhibitors in the treatment of postmenopausal women with metastatic breast cancer [full report]. Toronto (ON): Cancer Care Ontario (CCO); 2003 Oct [online update]. 22 p. (Practice guideline report; no. 1-5). [33 references]

First-line Therapy

• Anastrozole and letrozole are modestly superior to tamoxifen (in terms of objective response rate and time to disease progression) as first-line therapy for postmenopausal women with stage IV breast cancer and are the preferred treatment option in this setting.
• Tamoxifen remains an acceptable alternative.
• There are insufficient data to recommend any one aromatase inhibitor over others in this setting.

Second-line Therapy

• Anastrozole, letrozole, and exemestane are superior to megestrol acetate or aminoglutethimide as second-line hormonal therapy and are the preferred treatment option in this setting.
• There are insufficient data to recommend any one aromatase inhibitor over others in this setting.

Third- or Greater-line Therapy

For postmenopausal women with advanced breast cancer who have been heavily pretreated with hormonal agents and chemotherapy, exemestane is an acceptable therapy.

None provided

The recommendations are supported by randomized trials and meta-analyses.

• Breast Cancer Disease Site Group. The role of aromatase inhibitors in the treatment of postmenopausal women with metastatic breast cancer [full report]. Toronto (ON): Cancer Care Ontario (CCO); 2003 Oct [online update]. 22 p. (Practice guideline report; no. 1-5). [33 references]

Not applicable: The guideline was not adapted from another source.

2002 Sep 3 (revised online 2003 Oct)

Program in Evidence-based Care - State/Local Government Agency [Non-U.S.]

The Practice Guidelines Initiative (PGI) is the main project of the Program in Evidence-based Care (PEBC), a Province of Ontario initiative sponsored by Cancer Care Ontario and the Ontario Ministry of Health and Long-Term Care.

Cancer Care Ontario, Ontario Ministry of Health and Long-Term Care

Breast Cancer Disease Site Group

Members of the Breast Cancer Disease Site Group disclosed information on potential conflict of interest before discussing this practice guideline. DSG members acknowledged that their involvement in a clinical trial of tamoxifen versus exemestane presented a potential conflict of interest that could make them reluctant to recommend aromatase inhibitors in the first-line setting.

None available

This NGC summary was completed by ECRI on June 23, 2003. The information was verified by the guideline developer as of July 16, 2003. This summary was updated again on April 19, 2004. The information was verified by the guideline developer on April 29, 2004.