Tumor markers ovarian cancer

Serum cancer antigen 125 (CA-125) is the most extensively evaluated tumor marker for ovarian cancer. Unfortunately, the CA-125 determination is non-specific, and elevated levels can be associated with a number of other gynecologic and gastrointestinal diseases. CA-125 levels in a woman without ovarian cancer, though, are static or tend to decrease over time, whereas levels associated with malignancy will continue to rise.10 Since CA-125 is a non-specific marker, there is no standard recommendation for routine screening for prevention of ovarian cancer. 

Evaluation of CA 125 tests has shown moderate sensitivity, higher specificity, and predictive values in ovarian cancer patients when determining the presence of an intraperitoneal tumor or future occurrence at the time of second-look procedures. Studies have shown that the CA 125 level obtained at the time of a second-look procedure correlates reasonably well with the size of the tumor. As mentioned before, the predictive value of a marker depends on the prevalence of a particular type of malignancy in the intended population. Thus, evaluating a marker s diagnostic potential must be based on prevalence in a well-defined group for results to be generally applicable (i.e., prevalence of ovarian cancer in women with pelvic masses). 

In phase I clinical trials 47 patients, all of whom had previously failed standard treatments for solid tumors, received the drug in the UK, Italy, and Switzerland on three different schedules.123,124 Dose-limiting toxicities have been defined as bone marrow depression and diarrhea. The latter is treatable with loperamide. Signs of biological activity were seen. Notably one patient with metastatic pancreatic cancer showed a partial response (for 4 months) and two further patients, one with metastatic melanoma and one with bronchoalveolar carcinoma, also showed partial responses. In a phase I trial in combination with 5-FU, a partial response in breast cancer was observed.125 Furthermore, a reduction in tumor marker levels was observed in two patients, one with ovarian cancer, and one with colon cancer. Phase II studies have shown partial responses in cisplatin-resistant ovarian and nonsmall-cell lung cancer.126,127 The indications are that the profile of clinical activity is different and complementary to the mononuclear platinum agents. 

Canney PA, Moore M, Wilkinson PM, James RD, Ovarian cancer antigen CA 125 a prospective clinical assessment of its role as a tumor marker, Br. J. Cancer, 50 765-769, 1984. 

Gadducci, A. Cosio, S. Carpi, A. Nicolini, A. Genazzani, A.R. Serum tumor markers in the management of ovarian, endometrial and cervical cancer. Biomed. Pharmacother. 2004, 58 (1), 24-38. 

Shih IM, SokoU LJ, Chan DW. Ovarian cancer. In Diamandis EP, Fritsche HA, Lilja H, Chan DW, Schwartz MK, eds. Tumor markers Physiology, pathobiology, technology and clinical applications. Washington, DC AACC Press, 2002 239-52. 

Hempling RE. Tumor markers in epithelial ovarian cancer. Obstet Gynecol Clin North Am 1994 21 41-61. 

Although helpful in surveillance of patients with diagnosed ovarian cancer, the tumor marker CA-125 does not improve early detection of ovarian cancer when used alone [5]. Investigations examining genomic and pro-teomic patterns as possible complementary biomarkers for early ovarian cancer have shown some promise. However, further study is necessary to ascertain whether these biomarkers provide sufficient improvement in diagnostic accuracy to justify their more widespread application for ovarian cancer screening [19]. 

CA-125, a glycoprotein antigen, is currently the most commonly used tumor marker for ovarian cancer. However, elevation of CA-125 of more than 35 U/ml is not specific for epithelial ovarian cancer, but can be... 

Serum tumor markers (CA-125) are pivotal in the follow-up of patients with a history of ovarian cancer. A rising CA-125 level in a patient in a clinically complete remission is highly predictive of recurrence. However, this may precede the median time to physical or radiographic evidence of recurrent disease by 4-6 months [4]. 

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