An Open-label, Randomized Study Comparing 3 Years Tamoxifen Versus 3 Years Letrozole as Continuation of Adjuvant Treatment of Postmenopausal Women with Estrogen Receptor (ER) Positive and/or Progesterone Receptor (PR) Positive Early Breast Cancer Who Already Completed 2 years Adjuvant Tamoxifen. A Large Thai Multicenter Study.

Completed

Conditions: ER positive and/or PR positive early breast cancer
Cancer
Breast

Registration Number: ISRCTN05585365

Lead Sponsor: Thai Breast Cancer Study Group (Thailand)

Brief Summary: Not available

Detailed Description: Not available

Recruitment & Eligibility

Status: Completed

Sex: Female

Target Recruitment: 1000

Inclusion Criteria

1. Patients with stage I, II or IIIa adenocarcinoma of the breast at diagnosis. Patients with breast cancer whose tumor has been completely removed macroscopically and margins of the resected tumor have been microscopically free of tumor. If appropriate, additional local (e.g. radiotherapy) and/or systemic (i.e. adjuvant chemotherapy) treatments are allowed.
2. Postmenopausal status defined by one of the following:
a. Age =55 years with cessation of menses
b. Age <55 but no spontaneous menses for at least 1 year
c. Age <55 and spontaneous menses within the past 1 year, but currently amenorrheic (e.g. spontaneous, or secondary to hysterectomy), and with postmenopausal gonadotrophin levels (luteinizing hormone and follicle stimulating hormone levels >40 IU/l) or postmenopausal estradiol levels (<5 ng/dl) or according to the definition of 'postmenopausal range' for the laboratory involved
d. Bilateral oophorectomy
3. Patients whose tumors are either ER+ and/or PR+ (defined as ER and/or PR =10 fmol/mg cytosol protein; or =10% of the tumor cells positive by immunohistochemical evaluation)
4. Under tamoxifen therapy for 2 years before randomization
5. At randomization, patients must have no clinical or radiological evidence of distant metastasis, and no other concomitant malignancy (confirmed by mammography, chest X-ray or computed tomography [CT] scan, bone scan and liver US)
6. Eastern Cooperative Oncology Group (ECOG) performance status of 0?2
7. No prior treatment with letrozole
8. Patients must be accessible for follow-up
9. Signed written informed consent

Exclusion Criteria

1. Patients with any clinical or radiological evidence of distant spread of their disease at any point before randomization
2. Patients with other non-malignant systemic diseases including uncontrolled infections, uncontrolled type 2 diabetes mellitus, uncontrolled thyroid dysfunction, cardiovascular, renal, hepatic, and lung diseases which would prevent prolonged follow-up. Patients with previous history of thrombosis or thromboembolism can be included only if medically suitable. Patients with a known history of human immunodeficiency virus (HIV) are excluded.
3. Total serum calcium >2.75 mmol/l (11.0 mg/dl)
4. White Blood Cell Count (WBC) <3.0 x 10^9/l or granulocytes <1.5 x 10^9/l, platelets <100 x 10^9/l
5. Aspartate amino transferase (AST)/serum glutamic oxaloacetic transaminase (SGOT) and/or alanine amino transferase (ALT)/serum glutamic pyruvic transaminase (SGPT) >3 upper limit of normal (ULN) in combination with other laboratory and clinical abnormalities indicating liver insufficiency to a degree that precludes dosing with letrozole (Child-Pugh grade C)
6. Patients with abnormal renal function as defined by a serum creatinine =3 mg/dl (265.2 mmol/l)
7. Previous history of fracture within 2 years
8. Patients treated with other systemic investigational drug(s) and/or device(s) within the past 30 days
9. History of non-compliance to medical regimens and patients who are considered potentially unreliable
10. Mental illness that precludes the patient from giving informed consent

Study & Design

Study Type: Interventional

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Compare these treatment regimens in terms of disease free survival (DFS)

Secondary Outcome Measures

Name	Time	Method
1. Compare these treatment regimens in terms of overall survival (OS)<br>2. Compare these treatment regimens in terms of safety and tolerability in the Thai patient population