Exemestane Compared With Tamoxifen in Treating Women With Locally Recurrent or Metastatic Breast Cancer

DISEASE CHARACTERISTICS:

• Histologically or cytologically proven adenocarcinoma of the breast that is metastatic and progressive or locally recurrent and inoperable

• At least one bidimensionally measurable or evaluable lesion

  • Lytic bone lesions on x-ray/CT scan, surrounded by calcified bone, and at least 1 cm
  • Bidimensionally measurable extraosseous disease required for patients on bisphosphonates

  • The following are not considered evaluable:

    • Previously irradiated lesions
    • Lymphangitic spread
    • Ascites
    • Blastic bone lesions
    • Pleural effusions
• No rapidly progressive disease for which hormonal therapy is not indicated
• No massive visceral disease (i.e., more than one third of any organ)
• No brain metastases

• Hormone receptor status:

  • Estrogen receptor positive or progesterone receptor positive, defined by 1 of the following:

    • At least 10 femtomoles H3-estrogen or at least 20 femtomoles
    • H3 progesterone binding per mg of cytosol protein by DCC or sucrose density method
    • At least 0.10 femtomoles H3-estrogen or at least 0.20 femtomoles
    • H3-progesterone binding per mg of DNA by IF/EIA technique
    • Positive immunohistochemistry noted on pathology report

  • Unknown receptor status eligible provided:

    • Disease-free interval of at least 2 years since adjuvant therapy or initial surgery (if no adjuvant therapy), including most recently treated tumor in bilateral breast cancer if status unknown in one primary tumor

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Sex:

• Female

Menopausal status:

• Postmenopausal by 1 of the following:

  • Natural menopause and more than 1 year since last menstrual period (LMP)
  • Radiation-induced oophorectomy and more than 1 year since LMP

  • Chemotherapy induced menopause if:

    • At least 1 year since LMP (+ 1 year post-tamoxifen)
    • Serum FSH and LH and plasma estradiol levels in postmenopausal range
    • LHRH-induced amenorrhea

  • Surgical castration

    • Patients under age 56 with prior hysterectomy and 1 or both ovaries intact or tamoxifen-induced amenorrhea with at least 12 months since prior tamoxifen must have postmenopausal serum FSH and LH and plasma estradiol concentrations

Performance status:

• ECOG (WHO) 0-2

Hematopoietic:

• Absolute neutrophil count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3

Hepatic:

• Bilirubin less than 1.5 times upper limit of normal (ULN)
• SGOT/SGPT less than 2.5 times ULN (less than 5 times ULN with liver metastases)

Renal:

• Creatinine less than 1.5 times ULN

Cardiovascular:

• No deep venous thrombosis

Other:

• No mental incapacitation
• No severe concurrent disease
• No prior or concurrent malignancy except curatively treated carcinoma in situ of the cervix or basal cell or squamous cell skin cancer

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• No concurrent immunotherapy

Chemotherapy:

• See Disease Characteristics
• At least 3 weeks since chemotherapy for metastatic disease and recovered
• No more than 1 prior chemotherapy regimen for metastatic disease
• Prior adjuvant chemotherapy allowed if disease free for at least 6 months
• No concurrent chemotherapy

Endocrine therapy:

• No prior hormonal therapy for advanced disease (e.g., tamoxifen or LHRH agonists)
• Prior adjuvant tamoxifen allowed if disease free for at least 6 months
• No other concurrent hormonal therapy, including steroids

Radiotherapy:

• Recovered from toxic effects of prior radiotherapy
• Concurrent palliative radiotherapy, including whole brain irradiation, allowed

Surgery:

• See Disease Characteristics
• No prior ovariectomy for advanced disease

Other:

• No other concurrent investigational drugs
• Concurrent bisphosphonates allowed if short term (7 days) for hypercalcemia due to suspect tumor flare or if on prior bisphosphonates with bidimensionally measurable extraosseous lesion