Prognostic value of lymph node-to-primary tumor ratio of PET standardized uptake value for nasopharyngeal carcinoma: a recursive partitioning risk stratification analysis.

Background: Induction chemotherapy (IC) combined with concurrent chemoradiotherapy has become the standard treatment for locoregionally advanced nasopharyngeal carcinoma (LA-NPC). Data on the prognostic value of the lymph node-to-primary tumor ratio (NTR) of positron emission tomography (PET) standardized uptake value (SUV) for patients treated with IC were limited. Objectives: To evaluate the prognostic value of the SUV NTR for patients with LA-NPC treated with IC. Design: In all, 467 patients with pretreatment 18F-fluorodeoxyglucose PET/computed tomography (CT) scans between September 2017 and November 2020 were retrospectively reviewed. Methods: The receiver operating characteristic (ROC) analysis was used to determine the optimal cut-off value of SUV NTR. Kaplan-Meier method was used to evaluate survival rates. The recursive partitioning analysis (RPA) was performed to construct a risk stratification model. Results: The optimal cutoff value of SUV NTR was 0.74. Multivariate analyses showed that SUV NTR and overall stage were independent predictors for distant metastasis-free survival (DMFS) and regional recurrent-free survival (RRFS). Therefore, an RPA model based on the endpoint of DMFS was generated and categorized the patients into three distinct risk groups: RPA I (low risk: SUV NTR < 0.74 and stage III), RPA II (medium risk: SUV NTR < 0.74 and stage IVa, or SUV NTR ⩾ 0.74 and stage III), and RPA III (high risk: SUV NTR ⩾ 0.74 and stage IVa), with a 3-year DMFS of 98.9%, 93.4%, and 84.2%, respectively. ROC analysis showed that the RPA model had superior predictive efficacy than the SUV NTR or overall stage alone. Conclusion: SUV NTR was an independent prognosticator for distant metastasis and regional recurrence in locoregionally advanced NPC. The RPA risk stratification model based on SUV NTR provides improved DMFS and RRFS prediction over the eighth edition of the TNM (Tumor Node Metastasis) staging system.

Radiation-induced nasopharyngeal ulcers after re-irradiation with intensity-modulated radiotherapy in locoregional recurrent nasopharyngeal carcinoma patients: a dose-volume-outcome analysis.

OBJECTIVE: To analyze the interrelation between radiation dose and radiation-induced nasopharyngeal ulcer (RINU) in locoregional recurrent nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT). METHODS: Clinical data were collected from 363 patients with locoregional recurrent NPC who received re-irradiated with definitive IMRT from 2009 to 2017. Twenty-nine patients were diagnosed with RINU. Univariate and multivariate analyses were used to re-evaluate the first and second radiotherapy plans and to identify predictive dosimetric factors. RESULTS: All dosimetric parameters were notably associated with the progression to RINU (p < 0.01) using paired samples Wilcoxon signed rank tests. Multivariate analysis showed that EQD2_ [Formula: see text]D80 (dose for 80 percent volume of the unilateral nasopharynx lesion) was an independent prognostic factor for RINU (p = 0.001). The area under the ROC curve for EQD2_ [Formula: see text]D80 was 0.846 (p < 0.001), and the cutoff point of 137.035 Gy could potentially be the dose tolerance of the nasopharyngeal mucosa. CONCLUSIONS: The sum of equivalent dose in 2 Gy fractions (EQD2) in the overlapping volumes between initial and re-irradiated nasopharyngeal mucosal tissue can be effective in predicting the hazard of developing RINU in NPC patients undergoing radical re­irradiation with IMRT and we propose a EQD2_ [Formula: see text]D80 threshold of 137.035 Gy for the nasopharynx.

Prognostic value of circulating Epstein-Barr virus DNA level post-induction chemotherapy for patients with nasopharyngeal carcinoma: A recursive partitioning risk stratification analysis.

BACKGROUND: To evaluate the prognostic value of plasma Epstein-Barr virus (EBV) DNA level post-induction chemotherapy (IC) for patients with nasopharyngeal carcinoma (NPC). METHODS: A total of 893 newly diagnosed NPC patients treated with IC were retrospectively reviewed. The recursive partitioning analysis (RPA) was performed to construct a risk stratification model. The receiver operating characteristic (ROC) analysis was applied to determine the optimal cut-off value of post-IC EBV DNA. RESULTS: Post-IC EBV DNA levels and overall stage were independent predictors for distant metastasis-free survival (DMFS), overall survival (OS), and progression-free survival (PFS). The RPA model base on post-IC EBV DNA and overall stage categorized the patients into three distinct risk groups: RPA I (low-risk: stage II-III and post-IC EBV DNA < 200 copies/mL), RPA II (median-risk: stage II-III and post-IC EBV DNA ≥ 200 copies/mL, or stage IVA and post-IC EBV DNA < 200 copies/mL), and RPA III (high-risk: stage IVA and post-IC EBV DNA ≥ 200 copies/mL), with 3-year PFS of 91.1%, 82.6%, and 60.2%, respectively (p < 0.001). The DMFS and OS rates in different RPA groups were also distinct. The RPA model showed better risk discrimination than either the overall stage or post-RT EBV DNA alone. CONCLUSIONS: Plasma EBV DNA level post-IC was a robust prognostic biomarker for NPC. We developed an RPA model that provides improved risk discrimination over the 8th edition of the TNM staging system by integrating the post-IC EBV DNA level and the overall stage.

Failure pattern and suggestions for target volume delineation of carcinoma showing thymus-like differentiation treated with intensity-modulated radiotherapy.

BACKGROUND: To review our long-term clinical experience, analyze the failure patterns, and give suggestions for target volume delineation of carcinoma showing thymus-like differentiation (CASTLE) treated with intensity-modulated radiotherapy (IMRT). METHODS: From April 2008 to May 2019, 30 patients with CASTLE treated by postoperative or radical IMRT in our center were retrospectively reviewed. A total dose of 56-60 Gy in 28-30 fractions was prescribed to patients without residual disease and 66 Gy in 33 fractions for patients with residual or unresectable disease. Survival rates were calculated using the Kaplan-Meier method. Treatment-related toxicities were graded by National Cancer Institute Common Toxicity Criteria (NCI-CTC) version 4.0. RESULTS: Among the 30 patients, 12 (40%) received partial resection or biopsy. Lateral lymph node metastasis was observed in 7 (23.3%) patients. During follow-up, regional lymph node recurrence occurred in 2 patients and distant metastasis in 5 patients. With a median follow-up time of 63.5 months, the 5-year local recurrence-free survival (LRFS), regional recurrence-free survival (RRFS), distant metastasis-free survival (DMFS), overall survival (OS) and progression-free survival (PFS) rates were 100, 88.9, 78.9, 93.1 and 78.9%, respectively. For patients with no lateral neck node metastasis, prophylactic radiotherapy for lateral neck nodal regions failed to improve RRFS (p = 0.381) and OS (p = 0.153). CONCLUSION: Distant metastasis was the major failure pattern for CASTLE after surgery and IMRT. For patients with no lateral neck node metastasis, the omission of irradiation for lateral neck nodal regions seems to be safe and feasible.