Beyond evidence: reappraising use of CA-125 as post-therapy surveillance for ovarian cancer

Abstract

omen who have completed primary chemotherapy for ovarian cancer commonly have serial assessment of the serum tumour marker cancer antigen 125 (CA-125).1 This practice has been based on the proven utility of CA-125 in diagnostic algorithms and as a marker of response to therapy. Serial CA-125 assessment is also used because there is evidence that in women who have completed treatment for ovarian cancer, the serum CA-125 rises 2–6 months before symptoms or signs of relapse develop. The assumption underlying this and other similar studies is that serial monitoring of CA-125 would enable early diagnosis and treatment of relapse. This would thus lead to delay or reduction of cancer-related symptoms, psychological reassurance and, in theory, improved survival. Some studies have suggested that CA-125 may have some benefit in post-treatment surveillance. However, many others have demonstrated that although a rising CA-125 level is highly predictive of relapse, surveillance monitoring of CA-125 levels after remission from primary chemotherapy confers little benefit over standard clinical examination and does not improve duration of survival or quality of life.