BackgroundThis pilot trial is designed to determine whether PET/CT-guided radiotherapy dose escalation can improve local control while minimizing toxicity for the treatment of locally advanced nasopharyngeal carcinoma.Methods67 patients were randomized into the three treatment arms: conventional chemoradiotherapy (group A), CT-guided dose escalation chemoradiotherapy (group B) and PET/CT-guided dose escalation chemoradiotherapy (group C). Radiotherapy was delivered using the simultaneous modulated accelerated radiation therapy (SMART) technique in the dose-escalation treatment arms. Patients received concurrent and adjuvant chemotherapy.ResultsThe use of PET/CT significantly changed the treatment volume delineation of the gross tumor volume. 3-year local progression-free (LPF) survival rates of three groups were 83.3%, 90.9% and 100%, respectively. The 3-year regional progression-free survival (RPFS) rates were 95.8%, 95.5% and 100%, respectively. The 3-year disease free survival (DFS) rates were 79.2%, 86.4% and 95.2%, respectively. The 3-year overall survival (OS) rates were 83.3%, 90.9% and 95.2%, respectively. The 3-year disease-free survival (DFS) rates were 79.2%, 86.4% and 95.2%, respectively. No patient had grade 4 late toxicity.ConclusionsPET/CT-guided dose escalation radiotherapy is well-tolerated and appears to be superior to conventional chemoradiotherapy for locally advanced NPC.Trial RegistrationClinicalTrials.gov NCT02089204

Abstract. The objective of the present study was to investigate the association between thyroid gland-dosimetric parameters and hypothyroidism induced by intensity-modulated radiotherapy in patients with nasopharyngeal carcinoma (NPC). A total of 52 patients with NPC treated in the Department of Radiation Oncology of The Affiliated Hospital of Xuzhou Medical University, from May 2008 to December 2016 were retrospectively enrolled in the present study and divided into two groups based on thyroid function: The euthyroid and hypothyroid groups. The association between hypothyroidism and clinical or dosimetric parameters were analyzed. Females had a significantly increased probability of suffering from radiation-induced hypothyroidism (RIHT), compared with males (P= 0.010). The occurrence of RIHT was significantly negatively associated with thyroid volume prior to radiotherapy (P=0.048). Furthermore, the mean dose (Dmean) and V50 in the hypothyroidism group were significantly increased, compared with the euthyroidism group (P=0.017 and P=0.023, respectively). During the treatment optimization period, dose constraints associated with the thyroid gland demonstrated a significantly protective effect on thyroid function compared with the unconstrained group (P=0.034). According to the receiver operating characteristic curves, the threshold value was 5,160 cGy for Dmean and 54.5% for V50. The 3-year cumulative incidence of RIHT was 67.8% when the Dmean value was >5,160 cGy and 44.6% when the Dmean was <5,160 cGy (log rank test, P= 0.036). Furthermore, the 3-year cumulative incidence was 66.1% when the V50 was >54.5%, and 29.9% when the V50 was <54.5% (log rank test, P=0.025). In conclusion, RIHT is associated with radiation dose, particularly with Dmean and V50 of the thyroid gland. Dose constraints associated with the thyroid gland significantly reduced the incidence of hypothyroidism compared with the unconstrained group.

High‑dose total body irradiation (TBI) has an established role as preparative regimen for bone‑marrow transplantation in the treatment of chronic myelogenous leukemia (CML), but this regimen still has a relatively high rate of acute and late toxicity. Low‑dose radiation (LDR) induces apoptosis of tumor cells and has numerous beneficial effects on normal tissues, including radiation homeostasis and adaptive response. Based on the previous evidence, in the present study, K562 cells were exposed to LDR, high‑dose radiation (HDR), and LDR in combination with HDR to investigate the possible mechanism of the apoptotic effect and hypersensitivity induced by LDR. The apoptotic rate increased in all radiation groups in a time‑dependent manner. An upregulation of Bax protein expression and a downregulation of Bcl‑xl in a dose‑dependent manner in human leukemia K562 cells was observed. However, the expression of p53 protein did not change in all of the radiation cell groups. The mitochondrial membrane potential (ΔΨm) in K562 cells decreased in all of the radiation cell groups in a dose‑dependent manner. Furthermore, the decrease of ΔΨm was enhanced in the LDR/HDR group compared with that in the LDR or HDR groups. The activity of caspase‑3 was enhanced in all of the radiation groups. In the LDR/HDR group, the activity of caspase‑3 was higher than that in the HDR or LDR groups. The present study provided preliminary experimental evidence of LDR being beneficial in combination with TBI in the treatment of CML.

Objective: To make sure the feasibility with 18F FDG PET/CT to guided dynamic intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma patients, by dosimetric verification before treatment. Methods: Chose 11 patients in Ⅲ~ⅣA nasopharyngeal carcinoma treated with functional image-guided IMRT and absolute and relative dosimetric verification by Varian 23EX LA, ionization chamber, 2DICA of I'mRT Matrixx and IBA detachable phantom. Drawing outline and making treatment plan were by different imaging techniques (CT and 18F FDG PET/CT). The dose distributions of the various regional were realized by SMART. Results: The absolute mean errors of interest area were 2.39%±0.66 using 0.6cc ice chamber. Results using DTA method, the average relative dose measurements within our protocol (3%, 3 mm) were 87.64% at 300 MU/min in all filed. Conclusions: Dosimetric verification before IMRT is obligatory and necessary. Ionization chamber and 2DICA of I'mRT Matrixx was the effective dosimetric verification tool for primary focal hyper metabolism in functional image-guided dynamic IMRT for nasopharyngeal carcinoma. Our preliminary evidence indicates that functional image-guided dynamic IMRT is feasible.