Soluble IL-2 Receptor: A Prognostic Indicator in Head and Neck Cancer
Soluble IL-2 Receptor: A Prognostic Indicator in Head and Neck Cancer
ABSTRACT & COMMENTARY
Synopsis: The TNM classification for head and neck squamous cell cancer is useful, but it is not adequate for determining patients at risk for local recurrence, distant metastases, and survival. In this report, evidence is presented that measurement of serum soluble interleukin-2 receptor, obtained at the time of diagnosis, is a useful predictor of the development of metastases and overall survival in patients with this tumor type.
Source: Tartour E, et al. Lancet. 2001;357:1263-1264.
Tumor size, lymph node involvement, and the presence or absence of metastatic disease are useful prognostic indicators for head and neck squamous cell carcinoma (HNSCC), but additional indicators are needed to better predict which patients are likely to have aggressive disease and shorter survival. In an earlier study,1 Tartour and colleagues were to establish an association of high levels of soluble IL-2 receptor (sIL-2-R) and poor survival in 85 patients with HNSCC. In the current report, 234 HNSCC patients were examined in a prospective, multivariate study.
The 234 patients included 112 with tumors in the oral cavity, 33 with tumors in the oropharynx, 41 with hypopharynx tumors, and 48 with tumors of the larynx. Measurement of sIL2R was by ELISA and patients were either considered normal (< 70 pmol/L) or high (> 70 pmol/L). The 70 pmol/L level was chosen because that represents the 95th percentile in healthy people.
High sIL-2-R levels at diagnosis of HNSCC were correlated with shorter survival. At 3 years, the overall survival was 64.4% in patients with sIL-2-R in the normal range compared to 29.8% for patients with high sIL-2-R levels. Multivariate analysis (including TNM classification, primary tumor site, performance status, C-reactive protein, IL-6 levels, and sIL-2-R), only 4 variables influenced overall survival probability: serum sIL-2-R concentrations (P < .0001), lymph node involvement at diagnosis (P = .0015), performance status (P = .0001), and tumor stage (P = .0097).
Local recurrence and metastatic-free survival were also examined. A trend toward an association between serum sIL-2-R and local recurrence was observed, but this did not reach statistical significance (P = .081). The greatest predictors of local recurrence were initial tumor size (T score) and lymph node involvement. However, serum sIL-2-R concentrations were highly correlated with metastatic-free survival. Only 11.5% of patients with initially normal sIL-2-R levels developed distant metastases during the 3 years, compared to 34% of patients with high levels. In multivariate analysis, this reached a high level of significance (P = .0002). Thus, Tartour and colleagues suggest that initial serum sIL-2-R is a useful predictor of aggressive disease in patients with head and neck squamous cell carcinoma.
COMMENT by william B. Ershler, MD
This is an interesting report that expands earlier, and less complete findings from the same group that elevated sIL-2-R serum levels obtained at the time of diagnosis correlated with the development of metastatic disease and shorter survival. Inasmuch as this is a reliable and inexpensive assay (ELISA), if this work is confirmed by other investigators, it may become a useful initial diagnostic adjunct, particularly when questions regarding the advisability of systemic chemotherapy or postoperative radiation therapy are under consideration. Patients with elevated levels might be shown in future research to benefit from more aggressive adjuvant therapy.
Additional future research might also address the suitability of this marker (sIL-2-R) for assessing the completeness of surgery, the response to radiation or chemotherapy, and the early detection of recurrent disease. Indeed, if this is the case, sIL-2-R determination will become a routing measure in the management of these cases. However, other conditions may also be associated with elevated levels of sIL-2-R, including chronic or acute infections, or other malignancies. Thus, the findings are early, albeit intriguing. Hopefully, within a few years we’ll have the answers to these questions and possibly a new and useful tumor marker for head and neck cancer.
Reference
1. Tartour E, et al. Cancer. 1997;79:1401-1408.
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