L. Feng

Clinical observation of 73 nasopharyngeal carcinoma patients treated by helical tomotherapy: the China experience.

The preliminary short-term clinical outcome of 73 nasopharyngeal carcinoma (NPC) patients treated with helical tomotherapy at our cancer institute has been evaluated. Between September 2007 and September 2009, 73 newly diagnosed NPC patients were treated with helical tomotherapy. The distributions of clinical stages according to the UICC 2002 Staging System were: 6, 27, 24, and 16 for Stage I, IIa-b, III, and IVa-b, respectively. The prescription dose was 70–74 Gy/33F to planning gross tumor volume containing the primary tumor and positive lymph nodes, with 60–62.7 Gy/33F to high risk planning target volume, while delivering 52–56 Gy/33F to low risk planning target volume. Twenty-four patients were treated with radiation therapy as single modality, 25 with concurrent cisplatin-based chemotherapy with or without anti-EGFR monoclonal antibody therapy, and 24 with concurrent anti-EGFR monoclonal antibody therapy. Setup errors were analyzed. Side-effects were evaluated with the established RTOG/EORTC criteria. Average beam-on-time was 468.8 sec/F (396.7–696.1 sec). The setup errors in the lateral, longitudinal and vertical directions were 0.00 ± 1.79 mm, −0.55 ± 2.17 mm and 0.38 ± 1.43 mm, corresponding to 3.80 mm, 4.20 mm, and 2.46 mm as the CTV-PTV margin in these directions. The grade 0, 1, 2 and 3 acute skin toxicity was 2.7%, 76.7%, 13.8% and 6.8%; the grade 0, 1, 2 and 3 acute mucositis was 1.4%, 32.9%, 60.2% and 5.5%; and the grade 0, 1, 2 and 3 acute xerostomia was 4.0%, 45.3%, 50.7% and 0, respectively. Only 5 patients suffered from grade 3 or 4 leucopenia. Xerostomia resolved with passing of time and no grade 2 or more xerostomia was noted one year after radiation therapy. Concurrent chemotherapy significantly increased incidence of severe acute toxicities. One month after radiation therapy the remission rates of primary tumor and positive lymph nodes were 91.8% and 98.1%, respectively. The median follow-up was 14.8 months. The one-year relapse-free survival, distant metastasis-free survival and overall survival was 95.6%, 97.2% and 94.8%, respectively. In conclusion, the incidence of severe acute toxicities and late xerostomia was relatively infrequent for NPC patients treated with helical tomotherapy. The long-term clinical outcome for these patients is under investigation.

Clinical Study of Nasopharyngeal Carcinoma Treated by Helical Tomotherapy in China: 5-Year Outcomes

Background. To evaluate the outcomes of nasopharyngeal carcinoma (NPC) patients treated with helical tomotherapy (HT). Methods. Between September 2007 and August 2012, 190 newly diagnosed NPC patients were treated with HT. Thirty-one patients were treated with radiation therapy as single modality, 129 with additional cisplatin-based chemotherapy with or without anti-EGFR monoclonal antibody therapy, and 30 with concurrent anti-EGFR monoclonal antibody therapy. Results. Acute radiation related side effects were mainly grade 1 or 2. Grade 3 and greater toxicities were rarely noted. The median followup was 32 (3–38) months. The local relapse-free survival (LRFS), nodal relapse-free survival (NRFS), distant metastasis-free survival (DMFS), and overall survival (OS) were 96.1%, 98.2%, 92.0%, and 86.3%, respectively, at 3 years. Cox multivariate regression analysis showed that age and T stage were independent predictors for 3-year OS. Conclusions. Helical tomotherapy for NPC patients achieved excellent 3-year locoregional control, distant metastasis-free survival, and overall survival, with relatively minor acute and late toxicities. Age and T stage were the main prognosis factors.

Actual Anatomical and Dosimetric Changes of Parotid Glands in Nasopharyngeal Carcinoma Patients during Intensity Modulated Radiation Therapy

The goal of this study was to evaluate the actual anatomical and dosimetric changes of parotid glands in nasopharyngeal carcinoma patients during intensity modulated radiation therapy. With helical tomotherapy, its planning system, and adaptive software, weekly anatomical and dosimetric changes of parotid glands in 35 NPC patients were evaluated. Interweekly parotid volume varied significantly (P < 0.03). The rate of volume change reached the highest level at the 16th fraction. The average V 1 increased by 32.2 (left) and 28.6 (right), and the average D 50 increased by 33.9 (left) and 24.93 (right), respectively. Repeat data comparison indicated that the V 1 and D 50 varied significantly among different fractions (both with P = 0.000). The variation of parotid volume was inversely correlated with that of the V 1 and D 50 (both with P = 0.000). In conclusion, parotid volume and actual dose vary significantly in NPC patients during IMRT. Replanning at the end of the fourth week of IMRT may have clinical benefits.

A Dosimetric Analysis of Preoperative Intensity-modulated and Image-guided Radiation Therapy with and without Simultaneous Integrated Boost for Locally Advanced Rectal Cancer

Preoperative concurrent chemoradiation, total mesorectal excision and adjuvant chemotherapy have become the standard of care for patients with locally advanced rectal cancer (LARC). Several studies have reported increased pathologic complete response rates and improved locoregional control with escalating doses of preoperative radiotherapy. In this study, we assess the dosimetric feasibility and impact of intensity-modulated and image-guided radiation therapy (IMRT-IGRT) with a simultaneous integrated boost (SIB) in preoperative chemoradiation for LARC. Ten rectal cancer patients treated with preoperative chemoradiation were enrolled in this study, and IMRT56.25Gy and IMRT50Gy plans were made for each patient with a CTV-PTV50Gy margin of 5 mm and a GTV-PTV56.25Gy margin of 10 mm adapted to daily KV cone-beam computed tomography (CBCT) imaging. In the boost group (IMRT56.25Gy), the prescribed doses were 56.25 Gy to the gross tumor (PTV56.25Gy) and 50 Gy to areas at high risk of harboring microscopic disease (PTV50Gy). Doses were delivered over 25 daily fractions using a SIB technique. In the no-boost group (IMRT50Gy), the prescribed dose was 50 Gy to PTV50Gy without a boost. The goals were to give at least 95% of the prescribed doses to at least 95% of the PTVs while keeping irradiated volumes of the organs at risk dose as low as possible. Differences in dose distributions between the two sets of plans were analyzed using a paired sample t-test. All IMRT56.25Gy plans met the needs of the prescribed doses and organ at risk dose constraints. Compared to IMRT50Gy, the addition of a SIB in IMRT56.25Gy resulted in significant increases in mean dose and V40Gy to the bladder and significant increases of V30Gy and V40Gy to femoral heads (p < 0.05 for all points). There were no significant differences in dose to small bowel or pelvic bone marrow between the two sets of plans. Preoperative IMRT-IGRT with SIB for LARC is feasible dosimetrically with respect to organ at risk dose constraints. A phase II trial to evaluate the clinical safety and efficacy of this approach is being undertaken.

Replanning Criteria and Timing Definition for Parotid Protection-Based Adaptive Radiation Therapy in Nasopharyngeal Carcinoma.

The goal of this study was to evaluate real-time volumetric and dosimetric changes of the parotid gland so as to determine replanning criteria and timing for parotid protection-based adaptive radiation therapy in nasopharyngeal carcinoma. Fifty NPC patients were treated with helical tomotherapy; volumetric and dosimetric (D mean, V 1, and D 50) changes of the parotid gland at the 1st, 6th, 11th, 16th, 21st, 26th, 31st, and 33rd fractions were evaluated. The clinical parameters affecting these changes were studied by analyses of variance methods for repeated measures. Factors influencing the actual parotid dose were analyzed by a multivariate logistic regression model. The cut-off values predicting parotid overdose were developed from receiver operating characteristic curves and judged by combining them with a diagnostic test consistency check. The median absolute value and percentage of parotid volume reduction were 19.51 cm3 and 35%, respectively. The interweekly parotid volume varied significantly (p < 0.05). The parotid D mean, V 1, and D 50 increased by 22.13%, 39.42%, and 48.45%, respectively. The actual parotid dose increased by an average of 11.38% at the end of radiation therapy. Initial parotid volume, initial parotid D mean, and weight loss rate are valuable indicators for parotid protection-based replanning.