Aromasin Vs Arimidex Study As Initial Hormonal Therapy In Postmenopausal Women With Advanced/Recurrent Breast Cancer

• Time to Progression (TTP) - Investigators Assessment [ Time Frame: Up to 2008 days of the treatment ] [ Designated as safety issue: No ]
  Time in months from randomization to first documentation of objective tumor progression or death due to breast cancer, whichever comes first. Tumor progression was determined by the investigator using RECIST version 1.0 as an at least a 20% increase in the sum of the longest diameters (SLD) of the target lesions compared to the smallest SLD since the study treatment started. For participants with bone metastasis only, at least 25% increase in the measurable lesion according to General Rules for Clinical and Pathological Study of Breast Cancer (The 14th edition).
• Number of Participants With Objective Response - Investigators Assessment [ Time Frame: Up to 2008 days of the treatment ] [ Designated as safety issue: No ]
  Number of participants with objective response based assessment of confirmed complete response (CR) or confirmed partial response (PR) according to Response Evaluation Criteria in Solid Tumors (RECIST version 1.0). CR and PR are those that persist on repeat imaging study at least 4 weeks after initial documentation of response. CR was defined as the disappearance of all target and nontarget lesions and no appearance of new lesions. PR was defined as at least a 30% decrease in the sum of the longest diameters (SLD) of the targeted lesions. Objective Response (OR)= CR + PR.
• Number of Participants With Clinical Benefit - Investigator Assessment [ Time Frame: Up to 2008 days of the treatment ] [ Designated as safety issue: No ]
  Number of participants with clinical benefit based assessment of CR, PR or long-term stable disease (SD) according to the RECIST (version 1.0). CR and PR are those that persist on repeat imaging study at least 4 weeks after initial documentation of response. CR was defined as the disappearance of all target and nontarget lesions and no appearance of new lesions. PR was defined as at least a 30% decrease in the sum of the longest diameters (SLD) of the targeted lesions. Long-term SD was defined as SD lasted for at least 24 weeks (168 days). Clinical benefit = CR + PR + long SD
• Overall Survival (OS) [ Time Frame: Up to 2008 days of the treatment ] [ Designated as safety issue: Yes ]
  OS is defined as time from the date of randomization to the date of death.
• Time to Treatment Failure (TTF) [ Time Frame: Up to 2008 days of the treatment ] [ Designated as safety issue: Yes ]
  TTF is defined as the time from the randomization to the date of the first documentation of progressive disease (PD), symptomatic deterioration, death due to any cause, or treatment discontinuation due to adverse event, refusal or other reasons.

To verify the non-inferiority of exemestane compared to anastrozole in time to tumor progression (TTP), the primary efficacy endpoint, in postmenopausal women with advanced/recurrent breast cancer.

• Drug: exemestane
  take orally one tablet per day of exemestane 25 mg and one tablet per day of anastrozole placebo daily after meal
• Drug: anastrozole
  take orally one tablet of anastrozole 1 mg and one tablet of exemestane placebo daily after meal

• Experimental: 1
  Intervention: Drug: exemestane
• Experimental: 2
  Intervention: Drug: anastrozole

Inclusion Criteria:

• Have histologically or cytologically confirmed breast cancer at original diagnosis. At study entry, the patient must have metastatic progressive or locally recurrent inoperable breast cancer.

Exclusion Criteria:

• Having received any hormonal therapy (e.g., Tamoxifen, LHRH-agonists) ovariectomy or any chemotherapy for advanced/recurrent breast cancer