Shao Min Huang

Local control, survival, and late toxicities of locally advanced nasopharyngeal carcinoma treated by simultaneous modulated accelerated radiotherapy combined with cisplatin concurrent chemotherapy

The aim of this phase 2 study was to determine the long‐term local control, survival, and late toxicities among patients with locally advanced nasopharyngeal carcinoma (NPC) treated with intensity‐modulated radiotherapy (IMRT) with the simultaneous modulated accelerated radiation therapy (SMART) boost technique and concurrent chemotherapy.

Haemoglobin, Neutrophil to Lymphocyte Ratio and Platelet Count Improve Prognosis Prediction of the TNM Staging System in Nasopharyngeal Carcinoma: Development and Validation in 3237 Patients from a Single Institution

AIMS To improve prediction efficiency by incorporating complete blood count (CBC) into the TNM system on 5 year disease-specific survival (DSS) for patients with nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS The CBC of 3237 patients undergoing radiotherapy was retrospectively evaluated. In total, 2820 patients treated with non-intensity-modulated radiotherapy (IMRT) were randomly divided into development (1895 patients) and validation cohorts (925 patients). The association of potential risk factors with 5 year DSS was tested by Cox proportional hazards analysis and a prognostic index was created by assigning weighted scores proportional to a regression coefficient to each factor. Each cohort was divided into low, intermediate and high prognostic index. The prognostic index was validated in the validation cohort and compared with the TNM system on prediction of 5 year DSS. Validation was repeated in another independent group of 417 patients treated with IMRT. RESULTS Eight independent prognostic factors were identified: gender, age, T or N stages, anaemia or thrombocytosis during radiotherapy, continuous reduction in haemoglobin, high neutrophil-lymphocyte ratio before radiotherapy. Each was assigned a number of points. The area under curve (AUC) of the prognostic index was larger than that of Union Internationale Contre le Cancer/American Joint Cancer Committee TNM system 2009 (0.697 versus 0.619, P < 0.001). CONCLUSION A CBC-based prognostic index was developed and had a higher prediction efficiency on 5 year DSS in NPC than the TNM system alone.

A real-time in vivo dosimetric verification method for high-dose rate intracavitary brachytherapy of nasopharyngeal carcinoma.

PURPOSE A real-time in vivo dosimetric verification method using metal-oxide-semiconductor field effect transistor (MOSFET) dosimeters has been developed for patient dosimetry in high-dose rate (HDR) intracavitary brachytherapy of nasopharyngeal carcinoma (NPC). METHODS The necessary calibration and correction factors for MOSFET measurements in (192)Iridium source were determined in a water phantom. With the detector placed inside a custom-made nasopharyngeal applicator, the actual dose delivered to the tumor was measured in vivo and compared to the calculated values using a commercial brachytherapy planning system. RESULTS Five MOSFETs were independently calibrated with the HDR source, yielding calibration factors of 0.48 ± 0.007 cGy∕mV. The maximum sensitivity variation was no more than 7% in the clinically relevant distance range of 1-5 cm from the source. A total of 70 in vivo measurements in 11 NPC patients demonstrated good agreement with the treatment planning. The mean differences between the planned and the actually delivered dose within a single treatment fraction were -0.1% ± 3.8% and -0.1% ± 3.7%, respectively, for right and left side assessments. The maximum dose deviation was less than 8.5%. CONCLUSIONS In vivo measurement using the real-time MOSFET dosimetry system is possible to evaluate the actual dose to the tumor received by the patient during a treatment fraction and thus can offer another line of security to detect and prevent large errors.

Effect of total dose and fraction size on survival of patients with locally recurrent nasopharyngeal carcinoma treated with intensity-modulated radiotherapy: a phase 2, single-center, randomized controlled trial.

The optimal model of total dose and fraction size for patients with locally recurrent nasopharyngeal carcinoma treated with intensity‐modulated radiotherapy (IMRT) remains unclear. The authors designed a randomized phase 2 clinical trial to investigate the efficacy of 2 different models, with the objective of determining an optimal model.

Effect of total dose and fraction size on survival of patients with locally recurrent nasopharyngeal carcinoma treated with intensity-modulated radiotherapy

The optimal model of total dose and fraction size for patients with locally recurrent nasopharyngeal carcinoma treated with intensity‐modulated radiotherapy (IMRT) remains unclear. The authors designed a randomized phase 2 clinical trial to investigate the efficacy of 2 different models, with the objective of determining an optimal model.

Normal Tissue Complication Probability Model for Radiation-induced Temporal Lobe Injury after Intensity-modulated Radiation Therapy for Nasopharyngeal Carcinoma

PURPOSE To identify predictors for the development of temporal lobe injury (TLI) after intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma. MATERIALS AND METHODS Data in 351 patients with nasopharyngeal carcinoma treated with IMRT were reviewed retrospectively according to institutional ethics committee approval. Clinical factors associated with TLI were analyzed. Dose-volume histograms for 550 evaluable temporal lobes were analyzed, and the predictive value of therapy-associated and patient-associated factors for the occurrence of TLI was evaluated. Survival curves were depicted by using the Kaplan-Meier method and compared by using the log-rank test. Logistic regression analysis was used for multivariate analyses. RESULTS Median follow-up was 76 months (range, 6-100 months). Twenty-nine of 351 patients (8.3%) developed TLI; 21 patients had unilateral TLI, and eight had bilateral TLI. Median latency from IMRT until first TLI was 33 months (range, 12-83 months) among patients with TLI. The actuarial TLI-free survival rates were 94.4% and 91.3% at 3 and 5 years after radiation therapy, respectively. Logistic regression analysis demonstrated that dose delivered to a 1-cm(3) volume of the temporal lobe (D1cc) was the only independent predictor for TLI. The biologically equivalent tolerance doses at 2 Gy for a 5% and 50% probability of developing TLI were 62.83-Gy equivalents (95% confidence interval: 59.68, 65.97) and 77.58-Gy equivalents (95% confidence interval: 74.85, 80.32), respectively. CONCLUSION D1cc is predictive for radiation-induced TLI, suggesting that delivery of a high dose of radiation to a small volume of the temporal lobe is unsafe. A D1cc of 62.83 Gy by using a correction formula for varying fraction size may be the dose tolerance of the temporal lobe.

Prospective matched study on comparison of volumetric-modulated arc therapy and intensitymodulated radiotherapy for nasopharyngeal carcinoma: Dosimetry, delivery efficiency and outcomes

Background: The purpose of this study is to assess the feasibility of volumetric-modulated arc therapy (VMAT) for nasopharyngeal carcinoma (NPC) patients by comparing the physical dosimetry, delivery efficiency and clinical outcomes with intensity-modulated radiotherapy (IMRT). Methods: A prospective matched study was performed for patients with newly diagnosed NPC who underwent VMAT or IMRT. The patients in two groups were equally matched in terms of gender, age, tumor stage and chemotherapy. The target coverage, homogeneity index (HI) and conformity index (CI) of the planning target volume (PTV), organs at risk (OARs) sparing, average treatment time and clinical outcomes were analyzed. Results: From June 2013 to August 2015, a total of 80 patients were enrolled in this study, with 40 patients in each group. The coverage of PTV was similar for both groups. D2 was observed slight difference only in early stage disease (T1-2) (VMAT vs. IMRT, 7494±109 cGy vs. 7564±92 cGy; p=0.06). The HI of VMAT group was better than that of IMRT group (p=0.001), whereas CI was slightly worse (p=0.061). The maximum doses received by the brain stem, spinal cord, and optic nerve of VMAT were higher than those of IMRT (p<0.05). But the irradiation volumes in healthy tissue were generally lower for VMAT group, with significant differences in V20, V25 and V45 (p<0.05). With regard to the delivery efficiency compared with IMRT (1160 ± 204s), a 69% reduction in treatment time was achieved by VMAT (363 ± 162s). Both groups had 5 cases of nasopharyngeal residual lesions after radiotherapy. The 2-year estimated local relapse-free survival, regional relapse-free survival and locoregional relapse-free survival, distant metastasis-free survival, disease-free survival and overall survival were similar between two groups, with the corresponding rates of 100%, 97.4%, 97.4%, 90.0%, 90.0% and 92.4% in VMAT group, and 100%, 100%, 100%, 95.0%, 95.0% and 97.5% in IMRT group, respectively. Conclusions: Both VMAT and IMRT can meet the clinical requirements for the treatment of NPC. The short-term tumor regression rates and 2-year survival rates with the two techniques are comparable. The faster treatment time benefits of VMAT will enable more patients to receive precision radiotherapy.