White Button Mushroom Extract in Preventing the Recurrence of Breast Cancer in Postmenopausal Breast Cancer Survivors

DISEASE CHARACTERISTICS:

Meets 1 of the following criteria:

Prior diagnosis of infiltrating carcinoma of the breast ≥ 5 years prior to study entry
Prior diagnosis of ductal carcinoma in situ
No evidence of disease
Completed all cancer therapy, with the exception of reconstructive surgery, at least 6 months prior to study entry

Meets one of the following criteria:

Normal mammogram within 1 year of study entry
Underwent bilateral mastectomy and has been in remission for 5 years, as documented by an oncologist
Hormone receptor status not specified

PATIENT CHARACTERISTICS:

ECOG performance status 0-1
WBC ≥ 3,500/mm³
ANC ≥ 1,500/mm³
Platelet count ≥ 100,000/mm³
Hemoglobin ≥ 9.0 g/dL

Postmenopausal, defined as any of the following:

Continuous absence of menstruation for 12+ months
Status post bilateral oophorectomy
Status post hysterectomy with follicle-stimulating hormone in menopausal range
Creatinine ≤ 1.5 times upper limit of normal (ULN) or less
Total bilirubin ≤ 1.5 times ULN
AST and ALT < 2 times ULN
No allergy to mushrooms
No personal history of any invasive cancer, other than breast cancer, or squamous cell or basal cell skin cancer
No osteoporosis, defined as a bone-mineral density T-score of < -2.5 on dual-energy x-ray absorptiometry scan
No major systemic infections or other major medical illnesses of the cardiovascular, respiratory, or digestive system

PRIOR CONCURRENT THERAPY:

See Disease Characteristics

More than 3 months since prior and no concurrent hormone-modifying medications, including any of the following:

Oral contraceptives
Hormone replacement
Selective estrogen receptor modifiers
Other aromatase inhibitors
Gonadotropic-releasing hormone modifiers
At least 1 month since prior and no other concurrent mushroom extracts or DHEA as a dietary supplement
No concurrent therapy, except continued medications for unrelated illness that are not excluded, and necessary medications for unrelated acute illnesses that may occur during the study (e.g., cold, flu, or infection)

No more than 3 concurrent servings per week of the following foods:

Flaxseeds and flaxseed meal
High-energy bars or diet bars containing soy or soy protein
Liquid-nutrition drinks containing soy or soy protein (e.g., Odwalla Future Shake or Ensure Plus)
Miso soup
Natto
Packaged mixed dishes with soy or tofu (e.g., lasagna, burritos, or stir-fry)
Cooked soybeans or edamame (i.e., green soybeans)
Roasted soy nuts
Soymilk, regular or low-fat, plain or flavored
Soy cheese, such as cheddar, mozzarella, cram cheese, or parmesan (includes all foods made with soy cheese)
Soy protein powders (e.g., performance or body-builder powders)
Soy yogurt, all types
Soy sauce, tamari, teriyaki sauce, Szechuan sauce, or hoisin sauce
Soy ice cream, tofutti, or other soy desserts
Tempeh, all types
Tofu, all types, including low-fat, flavored, marinated, and smoked
Tofu or soy breakfast sausage, bacon, or other breakfast meat
Tofu or soy cold cuts, hot dogs, or other deli meat substitutes
Veggie soy or tofu burger, ground meat substitute (texturized vegetable protein), or soy or tofu, chicken, or turkey
Concurrent supplemental calcium and/or vitamin D and bisphosphonates allowed provided doses remain constant throughout the run-in and treatment portions of the trial