CA125 Serum Levels and Secondary Laparotomy in Epithelial Ovarian Tumours

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Abstract
EDITORIAL COMMENT: Late presentation of ovarian cancer remains a major problem in gynaecology and stimulates the search for an accurate tumour marker; a simple blood test at the time of regular gynaecological examination (cervical cytology, bimanual pelvic palpation, examination of the breasts) is what is needed! Cytology of fluid aspirated from the pouch of Douglas was found to be impractical and ultrasonography, although still to be fully evaluated, is unlikely to be costeffective. The ideal tumour marker would serve as both a screening test in asymptomatic women to detect early stage disease and as an accurate monitor of therapeutic response obviating the need for second‐look laparotomy. As shown in this paper, CA125 lacks the sensitivity required to fulfil these 2 aims due to the inability to detect small volume tumour. Serial measurements of this tumour marker may serve to indicate therapeutic response in patients with advanced disease, supplementing clinical and radiographic assessment but second‐look laparotomy still remains the most satisfactory means of establishing response to therapy.Summary: CA125 serum levels were assayed prior to 57 secondary laparotomies for ovarian epithelial tumours. Tumour was present in all 16 patients with an elevated level > 35 U/ml but the absence of tumour was incorrectly predicted in 15 of the 33 (45.5%) patients with CA125 levels < 35 U/ml. For these patients the CA125 level was elevated in 14 of 20 (70%) with tumour greater than 1.5 cm, 1 of 7 (14.3%) with macroscopic tumour less than or equal to 1.5 cm and 1 of 4 (25%) with microscopic tumour. Tumour was resectable to less than or equal to 0.5 cm in 7 of 12 (58.3%) patients with CA125 < 35 U/ml, 2 of 4 (50%) with CA125 in the range 35–100 U/ml and only 1 of 11 (9.1%) with CA125 > 100 U/ ml (p < .05). The CA125 level was elevated in 1 of 13 (7.7%) patients with less than 15 cm3 of tumour compared with 16 of 18 (88.9%) patients with 15 cm3 of tumour or more (p < .0001). The correlation between the CA125 serum level and the tumour volume was almost statistically significant (r =+ 0.31, p = .053). The level of CA125 was normal in all 8 patients with mucinous tumours — 4 of whom were found to have tumour at secondary surgery. Those patients in whom the CA125 level is normal or slightly elevated (up to 100 U/ml) are most likely to benefit from the second‐look laparotomy as they are significantly more likely either to be free of tumour or to have tumour which is resectable to 0.5 cm or less. We conclude that CA125 assay is a useful test when secondary laparotomy is envisaged.