Purpose: In contrast with other carcinoma cells, cells from nude mice transplanted undifferentiated carcinoma of nasopharyngeal type (UCNT) release the soluble fragment of the CD23 antigen (sCD23). We sought to study the level of sCD23 in sera of untreated UCNT patients.
Patients and methods: Pretherapeutic sera from 65 consecutive, locally advanced, initially nonmetastatic UCNT patients were assayed for sCD23. Patients were treated with a neoadjuvant chemotherapy/full-dose radiotherapy sequence. The mean follow-up duration is 50.5 months (range, 28 to 77). The Cox proportional hazards model was used to study the association between sCD23 levels and clinical signs and disease evolution.
Results: sCD23 levels showed an association with disease-free survival (DFS; P = .08) and overall survival (OVS; P = .08). Patients with sCD23 levels greater than a cutoff value of 0.6 ng/mL (greater cutoffs were found to be equally significant, but less sensitive), have a relative risk (RR) of relapse of 3.3 (95% confidence interval, 1.6 to 6.9; P = .002), and an RR of death of 2.9 (95% confidence interval, 1.2 to 7.3; P = .02), when taking other prognostic factors into account. CD23 does not correlate with either the response to treatment or the development of metastases, but appears to be related to local control (cutoff, 0.6 ng/mL; RR = 5.1 [95% confidence interval, 1.2 to 21.7]; P = .02).
Conclusion: The serum level of sCD23 appears to be an independent prognostic factor for initially nonmetastatic, locally advanced UCNT patients, treated with chemotherapy and radiotherapy. Our data indicate an association between this marker and local relapses. Thus, a simple enzyme-linked immunoadsorbent assay (ELISA) could help to identify a high-risk group among nonmetastatic UCNT patients. CD23 could be a marker for two groups of UCNT tumors, with distinct biologic characteristics and clinical behaviors.