Chun Yan Chen

Long-Term Outcomes of Early-Stage Nasopharyngeal Carcinoma Patients Treated With Intensity-Modulated Radiotherapy Alone

PURPOSE Reports of intensity-modulated radiotherapy (IMRT) for early-stage nasopharyngeal carcinoma (NPC) have been limited. The present study evaluated the long-term survival outcomes and toxicity of early-stage NPC patients treated with IMRT alone. METHODS AND MATERIALS Between February 2001 and January 2008, 198 early-stage (T1-T2bN0-N1M0) NPC patients had undergone IMRT alone. The data from these patients were retrospectively analyzed. The patients were treated to 68 Gy at 2.27 Gy/fraction prescribed to the planning target volume of the primary nasopharygeal gross tumor volume. The Radiation Therapy Oncology Group scoring system was used to assess the toxicity. RESULTS At a median follow-up of 50.9 months (range, 12-104), the 5-year estimated disease-specific survival, local recurrence-free survival, and distant metastasis-free survival rate was 97.3%, 97.7%, and 97.8%, respectively. The 5-year local recurrence-free survival rate was 100% for those with Stage T1 and T2a and 94.2% for those with Stage T2b lesions (p = 0.252). The 5-year distant metastasis-free survival rate for Stage T1N0, T2N0, T1N1, and T2N1 patients was 100%, 98.8%, 100%, and 93.8%, respectively (p = .073). All local recurrence occurred in patients with T2b lesions. Five patients developed distant metastasis. Of these 5 patients, 4 had had Stage T2bN1 disease and 1 had had Stage T2bN0 disease with retropharyngeal lymph node involvement. The most common acute toxicities were mainly Grade 1 or 2. At 24 months after IMRT, no Grade 3 or 4 xerostomia had developed, and 62 (96.9%) of 64 evaluated patients were free of trismus; only 2 patients (3.1%) had Grade 1 trismus. Radiation encephalopathy and cranial nerve injury were not observed. CONCLUSIONS IMRT alone for Stage T1N0, T2N0, T1N1, and T2N1 yielded satisfactory survival outcomes with acceptable toxicity, and no differences were found in survival outcomes among these four subgroups. Patients with Stage T2b lesions might have relatively greater risk of local recurrence and those with T2bN1 disease mighth have a greater risk of distant metastasis.

Treatment outcomes for different subgroups of nasopharyngeal carcinoma patients treated with intensity-modulated radiation therapy

Although many studies have investigated intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC), sample sizes in the reported studies are usually small and different in outcomes in different T and N subgroups are seldom analyzed. Herein, we evaluated the outcomes of NPC patients treated with IMRT and further explored treatment strategy to improve such outcome. We collected clinical data of 865 NPC patients treated with IMRT alone or in combination with chemotherapy, and classified all cases into the following prognostic categories according to different TNM stages: early stage group (T1–2N0–1M0), advanced local disease group (T3–4N0–1M0), advanced nodal disease group (T1–2N2–3M0), and advanced locoregional disease group (T3–4N2–3M0). The 5-year overall survival (OS), local relapse-free survival (LRFS), and distant metastases-free survival (DMFS) were 83.0%, 90.4%, and 84.0% respectively. The early disease group had the lowest treatment failure rate, with a 5-year OS of 95.6%. The advanced local disease group and advanced nodal disease group had similar failure pattern and treatment outcomes as well as similar hazard ratios for death (4.230 and 4.625, respectively). The advanced locoregional disease group had the highest incidence of relapse and death, with a 5-year DMFS and OS of 62.3% and 62.2%, respectively, and a hazard ratio for death of 10.402. Comparing with IMRT alone, IMRT in combination with chemotherapy provided no significant benefit to locoregionally advanced NPC. Our results suggest that the decision of treatment strategy for NPC patients should consider combinations of T and N stages, and that IMRT alone for early stage NPC patients can produce satisfactory results. However, for advanced local, nodal, and locoregional disease groups, a combination of chemotherapy and radiotherapy is recommended.

Analysis of dosimetric factors associated with temporal lobe necrosis (TLN) in patients with nasopharyngeal carcinoma (NPC) after intensity modulated radiotherapy

BackgroundThe radiation tolerance dose-volume in brain remains unclear for nasopharyngeal carcinoma (NPC) patients treated with intensity modulated radiotherapy (IMRT). We performed this study to investigate dosimetric factors associated with temporal lobe necrosis (TLN) in NPC patients treated with IMRT.MethodsFrom 2001 to 2008, 870 NPC patients were treated with IMRT. For the whole group, 40 patients have developed MRI-diagnosed TLN, and 219 patients were followed-up more than 60 months. Predictive dosimetric factors for TLN were identified by using univariate and multivariate analysis in these 259 patients.ResultsBy univariate analyses, rVX ( percent of temporal lobes receiving ≥ X Gy) and aVX ( absolute volumes of temporal lobes receiving ≥ X Gy, values of X considered were 10, 20, 30, 40, 50, 60, 66 and 70) were all significantly associated with TLN. Multivariate analysis by logistic regression showed that rV40 and aV40 were significant factors for TLN. All dosimetric factors in current serials were highly correlated one another (p < 0.001). The 5-year incidence of TLN for rV40 <10% or aV40 <5 cc is less than 5%. The incidence for rV40 ≥ 15% or aV40c ≥ 10c is increased significantly and more than 20%.ConclusionsIn this study, all dosimetric factors were highly correlated, rV40 and aV40 were independent predictive factors for TLN, IMRT with rV40 <10% or aV40 <5 cc in temporal lobe is relatively safe.

Prognostic Value of Cervical Nodal Necrosis in Nasopharyngeal Carcinoma: Analysis of 1800 Patients with Positive Cervical Nodal Metastasis at MR Imaging

PURPOSE To evaluate the prognostic value of cervical nodal necrosis (CNN) in patients with nasopharyngeal carcinoma (NPC) with magnetic resonance (MR) imaging. MATERIALS AND METHODS This was an institutional review board-approved retrospective study of 1800 patients with newly diagnosed stage T1, 4N1, 3M0 NPC who were treated with definitive radiation therapy, with or without chemotherapy, between January 2007 and December 2009; the requirement to obtain informed consent was waived. MR images were reviewed to assess lymph node status, and patients were divided into CNN and non-CNN groups. The overall survival, disease-free survival, regional relapse-free survival (RRFS), and distant metastasis-free survival (DMFS) were calculated with the Kaplan-Meier method, and differences were compared by using the log-rank test. RESULTS The incidence of CNN was 44.0% (792 of 1800). After the median follow-up period of 53 months, the 5-year overall survival, disease-free survival, RRFS, and DMFS rates of the CNN and non-CNN groups were 78.8% and 91.8%, 78.2% and 91.2%, 78.6% and 91.8%, and 78.4% and 91.6%, respectively (for all rates, P < .001). The distant metastasis rate was 18.7% (148 of 792) for the CNN group versus 4.6% (46 of 1008) for the non-CNN group (P < .01). Subgroup analysis revealed similar survival outcomes between stage N1 disease with CNN and stage N2 disease without CNN, stage N2 disease with CNN, and stage N3 disease regardless of CNN. CNN, T stage, N stage, age older than 44 years, and male sex were significant independent negative prognostic factors for overall survival, disease-free survival, RRFS, and DMFS. CONCLUSION CNN is an independent negative prognostic factor in patients with NPC, and it may be appropriate to investigate whether N stage should be upgraded by one level in patients with CNN.

Comparative study on prophylactic irradiation to the whole neck and to the upper neck for patients with neck lymph node–negative nasopharyngeal carcinoma

The purpose of this study was to investigate the prophylactic irradiation volume to neck drainage areas for patients with N0 classification nasopharyngeal carcinoma (NPC) treated by intensity‐modulated radiotherapy (IMRT).