The clinical value of serum CA125 levels in ovarian cancer patients receiving platinum therapy.

Serum CA125 concentrations are elevated in 60% (49/86) of patients, with histologically proven residual adenocarcinoma of the ovary, before chemotherapy. The frequency of elevated levels correlates with stage of disease and tumour size but not histological tumour type. Serial antigen determinations in 44 patients receiving monthly i.v. infusions of platinum therapy suggest that an elevated serum CA125 concentration after chemotherapy may identify the presence of residual tumour but a serum antigen level falling into the normal range does not always indicate the complete eradication of tumour. The role of this serum marker is limited by lack of sensitivity for small tumour masses.