CA 125 Levels in Treating Patients With Relapsed Advanced Ovarian Cancer, Fallopian Tube Cancer, or Primary Peritoneal Cancer Who Are Receiving Tamoxifen

OBJECTIVES: * Determine the percentage of patients with relapsed advanced ovarian carcinoma, fallopian tube carcinoma, or primary peritoneal carcinoma who have a log linear rise in CA 125 levels. * Determine whether the log linear part of the curve is consistent enough to allow comparison of the slope before and after introduction of a new therapy. * Compare the serial doubling time before and after commencing tamoxifen citrate treatment. * Determine the number of patients required to detect a significant difference in CA 125 doubling time before and after starting tamoxifen citrate treatment. OUTLINE: Patients undergo blood collection once a month to measure CA 125 levels. Once the CA 125 level goes above the upper limit of normal (ULN) or has started to rise from its nadir level (if not previously normal), CA 125 levels are measured every 2 weeks. When CA 125 levels reach 4 times the ULN or 4 times the nadir level (if not previously normal), patients begin oral tamoxifen citrate once daily for 3-6 months in the absence of disease progression or unacceptable toxicity. CA 125 levels will continue to be measured every 2 weeks during treatment. PROJECTED ACCRUAL: A total of 200 patients will be accrued for this study.