Background: The value of circulating CA 15-3 levels was assessed in 129 patients with recurrent breast carcinoma.
Methods: Patients were divided into four subgroups, according to the following: Group A, locoregional recurrence alone; Group B, locoregional and subsequent systemic recurrence; Group C, combined locoregional and systemic recurrence; and Group D, differing sites of systemic disease.
Results: One of 14 patients with locoregional disease alone had increased levels of CA 15-3 (> 25 U/ml). However, 96% of patients (22 of 23 patients) with combined local and systemic disease had increased tumor marker levels. The difference in CA 15-3 levels in patients with combined disease compared with patients with local disease alone was statistically significant (117.0 versus 17.5 U/ml, respectively; P < 0.02). Twenty-four patients with locoregional recurrence later had distant metastasis develop. In this group, patients with an increased CA 15-3 value had a significantly shorter lead time to the development of distant metastases compared with patients with normal tumor marker levels (20.8 +/- 3.3 versus 10.3 +/- 2.7 months, respectively; P < 0.03). CA 15-3 values at diagnosis were increased in 88% of 115 patients with metastatic disease. There was no significant difference in CA 15-3 levels among metastases to lung, liver, and bone nor was there any difference between single and multiple sites of distant metastasis. CA 15-3 is an excellent marker for systemic recurrence of breast carcinoma.
Conclusions: Increased levels and no clinical evidence of recurrence strongly indicate the presence of occult metastatic disease.