UTILITY OF C-ERBB-2 IN TISSUE AND IN SERUM IN THE EARLY DIAGNOSIS OF RECURRENCE IN BREAST-CANCER PATIENTS - COMPARISON WITH CARCINOEMBRYONIC ANTIGEN AND CA-15.3

To evaluate the utility of c-erbB-2, carcinoembryonic antigen (CEA) an d CA 15.3 in the early diagnosis of recurrence, serial serum determina tions of these antigens were performed in 200 patients (followup 1-4 y ears, mean 2.2 years) with primary breast cancer and no evidence of re sidual disease (NED) after radical treatment (radical mastectomy or si mple mastectomy and radiotherapy). Eighty-nine patients developed meta stases during follow-up. C-erbB-2, CEA and CA 15.3 were elevated (>20 U ml(-1), >10 ng ml(-1) or >60 U ml(-1) respectively) before diagnosis in 28%, 30% and 47% of the 89 patients with recurrence, with a lead t ime of 4.5 +/- 2.4, 4.9 +/- 2.4 and 4.8 +/- 2.4 months respectively. T umour marker sensitivity was clearly related to the site of recurrence , with the lowest sensitivity found in locoregional relapse and the hi ghest in patients with liver metastases. When patients with locoregion al recurrences were excluded, sensitivity improved: 31% (cerbB-2), 33% (CEA) and 56% (CA 15.3), with 76% having at least one of the three tu mour markers. C-erbB-2 sensitivity in early diagnosis was significantl y higher in patients with c-erbB-2 overexpression in tissue (8/10, 80% ) than in those without overexpression (1/30, 3.3%) (P = 0.0001). Like wise, higher levels of both, c-erbB-2 and CA 15.3 at diagnosis of recu rrence, higher sensitivity in early diagnosis of relapse and a higher lead time were found in PR(+) patients (CA 15.3, P < 0.0001) or in PR( -) patients (c-erbB-2, P = 0.009). Specificity of the tumour markers w as 100% for all three markers (111 NED patients). In conclusion, c-erb B-2 is a useful tool for early diagnosis of metastases, mainly in thos e patients with c-erbB-2 overexpression in tissue. Using all three mar kers simultaneously it is possible to increase the sensitivity in the early diagnosis of recurrence by 11.2%.