CA 125 Levels in Treating Patients With Relapsed Advanced Ovarian Cancer, Fallopian Tube Cancer, or Primary Peritoneal Cancer Who Are Receiving Tamoxifen
RATIONALE: Estrogen may cause the growth of ovarian cancer cells. Hormone therapy using tamoxifen may fight ovarian cancer by blocking the use of estrogen by the tumor cells. Measuring CA 125 levels may help doctors predict a patient's response to tamoxifen and help plan the best treatment. PURPOSE: This phase II trial is studying CA 125 levels in treating patients with relapsed advanced ovarian cancer, fallopian tube cancer, or primary peritoneal cancer who are receiving tamoxifen.