1.	Phase IV Study of Letrozole (Femara) as First-Line Therapy in Postmenopausal Women With Metastatic Breast Cancer (Summary Last Modified 07/2002) Phase: Phase IV Type: Treatment Status: Completed Age: 18 and over Sponsor: Pharmaceutical / Industry Protocol IDs: NOVARTIS-CFEM345A-US10, NCT00014638
2.	Treatment of Locally Advanced Breast Cancer With Letrozole in Postmenopausal Women Phase: Phase IV Type: Treatment Status: Closed Age: 18 and over Sponsor: Pharmaceutical / Industry Protocol IDs: CFEM345EBR01, NCT00237133
3.	Rheumatological Evaluation of Anastrozole and Letrozole as Adjuvant Treatment in Post-Menopausal Women With Breast Cancer Phase: Phase IV Type: Treatment Status: Closed Age: 50 and over Sponsor: Pharmaceutical / Industry Protocol IDs: CFEM345DUS59, NCT00688909
4.	Phase III Randomized Comparison Study of Letrozole Versus Tamoxifen as First-Line Therapy in Postmenopausal Women with Stage IIIB, Metastatic, or Recurrent Breast Cancer Phase: Phase III Type: Treatment Status: Closed Age: 18 and over Sponsor: Pharmaceutical / Industry Protocol IDs: NOVARTIS-2026701025, CGS-20267, NCI-V98-1388
5.	Phase III Randomized Study of Adjuvant Letrozole Versus Tamoxifen in Postmenopausal Women With Operable, Hormone Receptor-Positive Breast Cancer Phase: Phase III Type: Treatment Status: Closed Age: 30 and over Sponsor: Pharmaceutical / Industry Protocol IDs: IBCSG-1-98, DAN-DBCG-IBCSG-1-98, FRE-FNCLCC-IBCSG-1-98, EU-99022, IBCSG-18-98, NOVARTIS-2026703019, NCT00004205, BIG-I-98
6.	Phase III Study of Atamestane Plus Toremifene Versus Letrozole in Advanced Breast Cancer Phase: Phase III Type: Treatment Status: Completed Age: 18 and over Sponsor: Pharmaceutical / Industry Protocol IDs: Biomed 777-CLP-29, NCT00044291
7.	Phase III Randomized Study of Immediate Versus Delayed Zoledronate for Prevention of Bone Loss in Postmenopausal Women With Stage I-IIIA Breast Cancer Initiating Letrozole After Prior Treatment With Tamoxifen Phase: Phase III Type: Supportive care, Treatment Status: Closed Age: Postmenopausal Sponsor: NCI Protocol IDs: NCCTG-N03CC, NCT00107263, N03CC, NCCTG N03CC
8.	A Study to Evaluate the Effect of Letrozole and Tamoxifen on Bone and Lipids in Postmenopausal Women With Breast Cancer Phase: Phase III Type: Treatment Status: Completed Age: 50 and over Sponsor: Pharmaceutical / Industry Protocol IDs: CFEM345D2407, NCT00171704
9.	Comparison Trial of Letrozole to Anastrozole in the Adjuvant Treatment of Postmenopausal Women With Hormone Receptor and Node Positive Breast Cancer Phase: Phase III Type: Treatment Status: Completed Age: No age specified Sponsor: Pharmaceutical / Industry Protocol IDs: CFEM345D2411, NCT00248170
10.	Safety and Rheumatologic Tolerability of Letrozole in Postmenopausal Patients With Hormone Receptor Positive Breast Cancer Phase: Phase III Type: Treatment Status: Completed Age: 18 and over Sponsor: Pharmaceutical / Industry Protocol IDs: CFEM345DFR04, NCT00329940
11.	Phase II Randomized Study of Two Doses of Letrozole in Postmenopausal Women with Hormone-Refractory Metastatic Breast Cancer (Summary Last Modified 09/94) Phase: Phase II Type: Treatment Status: Closed Age: postmenopausal Sponsor: NCI Protocol IDs: NCCTG-933253, NCCTG-93-32-53
12.	Phase II Pilot Study of Letrozole plus Tamoxifen in Women with Metastatic Breast Cancer Phase: Phase II Type: Treatment Status: Completed Age: 18 and over Sponsor: NCI Protocol IDs: NCCTG-943252, NCCTG-94-32-52
13.	Phase II Randomized, Open-Label Study of Letrozole Alone vs Letrozole plus Tamoxifen as First-Line Therapy in Postmenopausal Women with Advanced Breast Cancer (Summary Last Modified 06/97) Phase: Phase II Type: Treatment Status: Closed Age: 18 and over Sponsor: Pharmaceutical / Industry Protocol IDs: CG-01026, NCI-V96-1015
14.	Phase II Study of Letrozole in Women With Recurrent or Metastatic Endometrial Cancer (Summary Last Modified 11/2000) Phase: Phase II Type: Treatment Status: Closed Age: 18 and over Sponsor: Pharmaceutical / Industry Protocol IDs: CAN-NCIC-IND126, NOVARTIS-FEM-CA-02, NCT00004251, IND126
15.	Phase II Pilot Study of cDNA Microarray as a Measure of Tumor Response to Neoadjuvant Docetaxel and Capecitabine Followed By Surgery and Adjuvant Doxorubicin and Cyclophosphamide in Patients With Stage II or III Breast Cancer Phase: Phase II Type: Diagnostic, Treatment Status: Completed Age: 18 and over Sponsor: NCI Protocol IDs: NCI-00-C-0149, NCT00020241
16.	Phase II Randomized Study of Letrozole With or Without Tipifarnib in Women With Locally Advanced, Locoregionally Recurrent, or Metastatic Breast Cancer That Has Progressed After Antiestrogen Therapy Phase: Phase II Type: Treatment Status: Closed Age: Medically or surgically postmenopausal Sponsor: NCI, Pharmaceutical / Industry Protocol IDs: CWRU-JJPR-1102, JJPRD-R115777-INT-22, NCT00060177
17.	Phase II Randomized Study of Letrozole With or Without CCI-779 in Postmenopausal Women With Locally Advanced or Metastatic Breast Cancer Phase: Phase II Type: Treatment Status: Closed Age: 18 and over Sponsor: NCI, Pharmaceutical / Industry Protocol IDs: CWRU-080234, CWRU-WAGM01102, WYETH-C-3066A1-204-WW, NCT00061971
18.	Phase II Study of Neoadjuvant Letrozole for Postmenopausal Women With Estrogen- and/or Progesterone-Receptor Positive Stage II, IIIA, or IIIB Breast Cancer Phase: Phase II Type: Treatment Status: Closed Age: Postmenopausal Sponsor: NCI Protocol IDs: WU-03-0586, NCT00084396, UCSF-02755, UCSF-H8409-21398-04
19.	Phase II Randomized Pilot Study of Letrozole in Postmenopausal Women at Increased Risk For Breast Cancer Based on Elevated Estradiol Levels Phase: Phase II Type: Prevention Status: Completed Age: 35 and over Sponsor: NCI Protocol IDs: DFCI-00024, UCLA-0210012-02, NCT00090857
20.	Phase II Study of Letrozole and Celecoxib as First-Line Therapy in Postmenopausal Women With Hormone Receptor-Positive Locally Advanced or Metastatic Adenocarcinoma of the Breast Phase: Phase II Type: Treatment Status: Closed Age: 18 and over Sponsor: NCI Protocol IDs: CINJ-NJ1103, CINJ-5076v3, CINJ-040402, UMDNJ-4761, NCT00101062
21.	Everolimus and Letrozole as Preoperative Therapy of Primary Breast Cancer in Post-Menopausal Women Phase: Phase II Type: Treatment Status: Completed Age: 18 and over Sponsor: Pharmaceutical / Industry Protocol IDs: CRAD001C2222, NCT00107016
22.	Phase II Randomized Chemoprevention Study of Letrozole in Postmenopausal Women Who Are at Increased Risk for the Development or Recurrence of Breast Cancer Due to High Breast Density Phase: Phase II Type: Prevention Status: Closed Age: Postmenopausal Sponsor: Other Protocol IDs: CAN-NCIC-MAP1, NCT00238316, MAP1
23.	Phase II Open Label Trial for Post-Menopausal Women With Newly Diagnosed Operable Breast Cancer Phase: Phase II Type: Treatment Status: Completed Age: 60 and over Sponsor: Other Protocol IDs: F041222006, UAB 0467, NCT00161291
24.	Concomitant and Sequential Radiohormonotherapy in Adjuvant Breast Cancer Phase: Phase II Type: Treatment Status: Completed Age: 18 and over Sponsor: Other Protocol IDs: CO-HO-RT/2004/31, NCT00208273
25.	Comparison Study of Letrozole Alone or Letrozole With Zoledronic Acid in Early Breast Cancer, Neoadjuvant Therapy Phase: Phase II Type: Treatment Status: Completed Age: 65 and over Sponsor: Pharmaceutical / Industry Protocol IDs: CZOL446GCA08, NCT00247650