Long-term outcome and late toxicities of simultaneous integrated boost-intensity modulated radiotherapy in pediatric and adolescent nasopharyngeal carcinoma

The application of simultaneous integrated boost-intensity modulated radiotherapy(SIB-IMRT)in pediatric and adolescent nasopharyngeal carcinoma(NPC)is underevaluated.This study aimed to evaluate long-term outcome and late toxicities in pediatric and adolescent NPC after SIB-IMRT combined with chemotherapy.Thirty-four patients(aged 8–20 years)with histologically proven,non-disseminated NPC treated with SIB-IMRT were enrolled in this retrospective study.The disease stage distribution was as follows:stage I,1(2.9%);stage III,14(41.2%);and stage IV,19(55.9%).All patients underwent SIBIMRT and 30 patients also underwent cisplatin-based chemotherapy.The prescribed dose of IMRT was64–68 Gy in 29–31 fractions to the nasopharyngeal gross target volume.Within the median follow-up of 52months(range,9–111 months),1 patient(2.9%)experienced local recurrence and 4(11.8%)developed distant metastasis(to the lung in 3 cases and to multiple organs in 1 case).Four patients(11.8%)died due to recurrence or metastasis.The 5-year locoregional relapse–free survival,distant metastasis–free survival,disease-free survival,and overall survival rates were 97.1%,88.2%,85.3%,and 88.2%,respectively.The most common acute toxicities were grades 3–4 hematologic toxicities and stomatitis.Of the 24 patients who survived for more than 2 years,16(66.7%)and 15(62.5%)developed grades 1–2 xerostomia and ototoxicity,respectively.Two patients(8.3%)developed grade 3 ototoxicity;no grade 4 toxicities were observed.SIB-IMRT combined with chemotherapy achieves excellent long-term locoregional control in pediatric and adolescent NPC,with mild incidence of late toxicities.Distant metastasis is the predominant mode of failure.

Prognostic scoring system for locoregional control among the patients with nasopharyngeal carcinoma treated by intensity-modulated radiotherapy

The prognostic value of T category for locoregional control in patients with nasopharyngeal carcinoma(NPC)has decreased with the extensive use of intensity-modulated radiotherapy(IMRT).We aimed to develop a prognostic scoring system(PSS)that incorporated tumor extension and clinical characteristics for locoregional control in NPC patients treated with IMRT.The magnetic resonance imaging scans and medical records of 717 patients with nonmetastatic NPC treated with IMRT at Sun Yat-sen University Cancer Center between January 2003 and January 2008 were reviewed.Age,pathologic classification,primary tumor extension,primary gross tumor volume(GTV-p),T and N categories,and baseline lactate dehydrogenase(LDH)level were analyzed.Hierarchical cluster analysis as well as univariate and multivariate analyses were used to develop the PSS.Independent prognostic factors for locoregional relapse included N2–3 stage,GTV-p≥26.8 mL,and involvement of one or more structures within cluster3.We calculated a risk score derived from the regression coefficient of each factor and classified patients into four groups:low risk(score 0),intermediate risk(score>0 and≤1),high risk(score>1 and≤2),and extremely high risk(score>2).The 5-year locoregional control rates for these groups were 97.4%,93.6%,85.2%,and 78.6%,respectively(P<0.001).We have developed a PSS that can help identify NPC patients who are at high risk for locoregional relapse and can guide individualized treatments for NPC patients.