title: Parametric contrast-enhanced ultrasound as an early predictor of radiation-based therapeutic response for lymph node metastases of nasopharyngeal carcinoma.
abstract: Nasopharyngeal carcinoma (NPC) is a common type of cancer in South East Asia with peculiar epidemiology, pathology, clinical behavior and response to treatment characteristics. To the best of our knowledge, this is the first study to investigate the use of a contrast-enhanced ultrasound (CEUS) as a predictor for the therapeutic response in lymph node metastases of NPC patients treated with radiation-based therapy. Sixty-seven NPC patients with lymph node metastases underwent the lymph nodes CEUS examination twice; pre- and in-treatment (at the 5th fraction radiotherapy), respectively. The CEUS parameters were acquired through Qontrast_4.0 software and mainly included peak intensity (PI) and time to peak (TTP). The response assessment at the lymph nodes revealed a complete response (CR) in 48 patients and partial response (PR) in 19 patients. There was a significant difference in pre-treatment PI (PIpre) between the patients who showed CR or PR, but the predicted sensitivity and specificity of PIprewas low. The mean in-treatment PI (PIin) value of the lymph nodes that achieved a CR was 34.24±3.78%, which was significantly higher than the PIinvalue for PR, 25.62±2.30% (P<0.001). Furthermore, the PIratio, a PI-quotient, was calculated by dividing the PIinby the corresponding PIpre. The higher PIratiowas also observed in CR lymph nodes (0.81±0.01 vs. 0.66±0.01; P=0.001), and the mean change in PI (PIΔ; PIΔ= PIpre-PIin) was smaller in the patients with CR nodes compared to the patients with PR nodes (7.79±3.28 vs. 13.77±1.90%; P=0.000). No difference was observed in TTPpreor TTPinbetween the CR or PR lymph nodes patients. A receiver operating characteristic curve was constructed to assess the accuracy of the parameters for the prediction of the therapeutic responses. The sensitivity and specificity of PIinin predicting the therapeutic response was 94.3 and 88.2%, and the corresponding figures of the PIratiowere 92.5 and 83.8%, respectively. The CEUS parameters during the early course of radiation-based therapy, PIinand PIratio, are associated with the therapeutic response of NPC lymph node metastases, with a high predicted sensitivity and specificity, thus yielding the conceivable predictors with the potential to individualize treatment.
authors: Department of Radiation Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, P.R. China.
authors: Zhimin
authors: Z
authors: Ye
authors: Department of Ultrasound, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, P.R. China.
authors: Pintong
authors: P
authors: Huang
authors: Department of Radiation Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, P.R. China.
authors: Xiaofeng
authors: X
authors: Zhou
authors: Department of Physiology, Zhejiang University School of Medicine, Hangzhou 310058, P.R. China.
authors: Qian
authors: Q
authors: Huang
authors: Department of Radiation Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, P.R. China.
authors: Qiongge
authors: Q
authors: Hu
authors: Department of Radiation Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, P.R. China.
authors: Yongjie
authors: Y
authors: Shui
authors: Department of Radiation Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, P.R. China.
authors: Li
authors: L
authors: Shen
authors: Department of Physiology, Zhejiang University School of Medicine, Hangzhou 310058, P.R. China.
authors: Enyin
authors: E
authors: Lai
authors: Department of Radiation Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, P.R. China ; National Ministry of Education Key Laboratory of Cancer Prevention and Intervention, Zhejiang University School of Medicine, Hangzhou 310009, P.R. China.
authors: Qichun
authors: Q
authors: Wei
keywords: contrast-enhanced ultrasound; lymph node metastasis; nasopharyngeal carcinoma; parametric imaging; therapeutic response