SERUM CA-125 LEVEL IN END-STAGE RENAL-DISEASE PATIENTS MAINTAINED ON CHRONIC PERITONEAL-DIALYSIS OR HEMODIALYSIS - THE EFFECT OF CONTINUOUS PRESENCE OF PERITONEAL-FLUID, PERITONITIS, AND PERITONEAL CATHETER IMPLANTATION

Serum CA-125, an ovarian tumor marker, is used to screen and follow up patients with ovarian cancer. Normal values (< 35 U/ml) have been reported in patients with end-stage renal disease and patients maintained on chronic hemodialysis (HD). Non-malignant ascites has been associated with high serum levels of CA-125, suggesting that the presence of fluid in the peritoneal cavity may stimulate its release. We studied 38 HD and 43 chronic ambulatory peritoneal dialysis (CAPD) patients with regard to serum CA-125 levels. In the HD patients, the mean +/- SE serum CA-125 level was 10.1 +/- 1.7 U/ml (range <5-39) with 8% of the patients having serum levels of > 35 U/ml. In the CAPD patients, the mean serum CA-125 level in all samples collected (n = 68) was 17.7 +/- 2.7 U/ml (range < 5-101, p < 0.01 vs. HD) with 16% of the sera showing levels of > 35 U/ml. The high serum CA-125 levels in the CAPD patients were from sera obtained within 2 months of diagnosis of peritonitis, peritoneal dialysis (PD) catheter implantation, or intra-abdominal surgery. When serum samples from this 2-month period were excluded, the mean serum CA-125 level was 8.9 +/- 1.5 U/ml (p = NS vs. HD) and only 1 patient had an abnormal level. Peritoneal dialysate CA-125 levels during an episode of peritonitis were significantly higher than at the baseline (69.1 +/- 14.2 vs. 2 1 +/- 2.5, p = 0.004) and both were significantly higher than the serum levels (p < 0.0001). Serum CA-125 levels were also the same in both sexes and races. In conclusion, it was found that while the serum CA-125 level is within normal limits in the majority of HD and stable CAPD patients, it is not uncommon that it is elevated in CAPD patients within 2 months of peritonitis, PD catheter placement, or intra-abdominal surgery, particularly when peritoneal exchanges are temporarily on hold in the latter two. The serum CA-125 level should be interpreted with caution in the CAPD patients as it may be a non-specific marker of peritoneal irritation. It was also found that there was a significant removal of CA-125 by the peritoneal fluid which markedly increased during episodes of peritonitis.