Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (782 page)

   Most of the commercially available assays quote the upper reference limit of 35 IU/mL; some studies have shown that the detection of disease can be significantly improved by lowering the cutoff value.

   Normal concentration of CA-125 does not exclude tumor.

   CA-125 is not useful for distinguishing benign from malignant pelvic masses, even at high concentrations.

   Although CA-125 may be increased ≤12 months before clinical evidence of disease, it is not recommended for screening women for serous carcinoma of the ovary because it is not increased in 20% of cases at the time of diagnosis and in <10% of stage I and II cases (low sensitivity and specificity; high false-positive rate).

   There is little benefit to early detection of late-stage cancers.

   Postoperative monitoring for persistent or recurrent disease; poorer prognosis if elevated 3–6 weeks after surgery.

   Lower levels in patients with no residual tumor or <2 cm of residual tumor.

   Concentration >35 U/mL detects residual cancer in 95% of patients, but a negative test does not exclude residual disease.

   Rising level of CA-125 during chemotherapy is associated with tumor progression, and fall to normal is associated with response. It remains elevated in stable or progressive serous carcinoma of the ovary.

   Rising concentrations may precede clinical recurrence by many months and may be indication for second-look operation, but lack of increased values does not indicate the absence of persistent or recurrent tumor.

   Greater concentration is roughly related to poorer survival; >35 U/mL is highly predictive of tumor recurrence.

   With values >65 U/mL, 90% of women have cancer involving the peritoneum.

   Higher levels are also seen in serous cystadenocarcinoma.