Prediction of survival and therapy outcome with C-11-tyrosine PET in patients with laryngeal carcinoma

Abstract

Choosing the optimal treatment for an individual with squamous cell carcinoma of the head and neck is a difficult challenge because of the unpredictable clinical behavior of this malignancy. A reliable method for assessing the clinical behavior and predicting the radiocurability of tumors would assist in the therapy strategy and prognosis. This study evaluated whether quantitative PET using L-[1-C-11]-tyrosine (TYR) has predictive value for survival and therapy outcome in patients with primary squamous cell carcinoma of the larynx. Methods: Thirty-four patients with histologically confirmed laryngeal carcinomas underwent dynamic C-11-TYR PET before receiving definitive therapy. Various methods for quantification of tumor activity were used: assessment of protein synthesis rate (PSR), calculation of standardized uptake value, and estimation of tumor-to-nontumor ratio. Treatment consisted of radiotherapy (n = 20) or surgery (n 14). The median follow-up was 40 mo. Results: All malignancies were identified correctly, with no false-negative results. Cumulative survival was compared between patients with tumor PSR equal to or higher than the median (2.0 nmol/ml/min) and those with tumor PSR lower than the median and was found not to be significantly different (P 0.07). When the radiotherapy group was evaluated separately, the difference in survival was significant (P = 0.03; 5-y survival, 30% vs. 73%) and high C-11-TYR uptake correlated with poor prognosis. In multivariate analysis, PSR was an independent predictor for survival. Because differences (P = 0.08) between patients with and patients without recurrence were not significant, no predictive value of PSR for disease recurrence could be demonstrated. Conclusion: Prediction of survival of patients undergoing radiotherapy for laryngeal squamous cell carcinoma is feasible primarily by using C-11-TYR PET to quantify activity before treatment