A retrospective study comparing the outcomes and toxicities of intensity-modulated radiotherapy versus two-dimensional conventional radiotherapy for the treatment of children and adolescent nasopharyngeal carcinoma

Abstract

PurposeTo compare the clinical outcomes and toxicities of two-dimensional conventional radiotherapy (2D-CRT) and intensity-modulated radiotherapy (IMRT) for the treatment of children and adolescent nasopharyngeal carcinoma (NPC).MethodsA total of 176 children with non-metastatic NPC treated at Sun Yat-sen University Cancer Center between October 2003 and September 2013 were included in this study. Of the 176 patients, 74 received 2D-CRT and 102 were treated with IMRT. The clinical outcomes and acute and late toxicities were determined and compared.ResultsThe IMRT group achieved significantly higher overall survival (OS) (90.4% vs. 76.1% at 5 year, P = 0.007) and disease-free survival (DFS) (85.7% vs. 71.2%, P = 0.029) mainly due to an improvement in locoregional relapse-free survival (LRRFS) (97.9 vs. 88.3%, P = 0.049). After stratification by disease stage, IMRT provided significant benefits for patients with stage III–IV disease in terms of OS, LRRFS and DFS. Multivariate analyses indicated that the treatment group (2D-CRT vs. IMRT) was a prognostic factor for OS, LRRFS and DFS. A significant reduction in Grade 2–4 xerostomia (52.7 vs. 34.3%, P = 0.015) and hearing loss (40.5 vs. 22.5%, P = 0.010) was observed in patients treated by IMRT.ConclusionIMRT provides better locoregional relapse-free survival and overall survival, especially in late-stage children and adolescent NPC patients, and is associated with a lower incidence of Grade 2–4 xerostomia as well as hearing loss compared with 2D-CRT. Distant metastasis remains a challenge in the treatment of children and adolescent NPC.

Clinical Implications of Plasma Epstein–Barr Virus DNA in Children and Adolescent Nasopharyngeal Carcinoma Patients Receiving Intensity-Modulated Radiotherapy

“…In young patients, the predominant histology of NPC is an undifferentiated variant of disease (27)(28)(29), which was confirmed in our study where 98.0% of pediatric patients were histologically WHO type III. On the other hand, ∼96.0% of our patients presented in advanced clinical stage III or IV, similar to other reports with stage III-IV patients accounting for 92.0-97.3% (5,7,29).…”

“…In the current study, IMRT has provided excellent locoregional control in children and adolescent NPC patients with LRRFS of 95.2%. Nevertheless, the NPC failure pattern was not altered by IMRT, and distant metastasis remained the major pattern of failure, a result similar to the findings of other reports (5,35,36). We observed that a level of pretreatment EBV DNA >40,000 copies/mL was highly statistically significantly associated with the poorer DMFS and DFS.…”

“…Radiotherapy (RT) is the primary treatment modality, and concurrent chemoradiotherapy with or without neoadjuvant/adjuvant chemotherapy is regarded as the standard of care for patients with locoregionally advanced NPC. In recent years, intensity-modulated radiation therapy (IMRT), which is associated with superior disease control and a lower treatment toxicity profile, has gradually replaced twodimensional conventional radiotherapy as the mainstay RT technique for children and adolescent NPC patients (5).…”

“…Several clinical features, including age, gender, stage, RT technique, RT dose, and response to chemotherapy can predict the prognosis in children with NPC (5)(6)(7)(8)(9)(10). However, the variable outcomes of patients within heterogeneous subgroups suggest that clinical features alone cannot precisely predict the treatment outcome.…”

Prognostic value of gross tumor regression and plasma Epstein Barr Virus DNA levels at the end of intensity-modulated radiation therapy in patients with nasopharyngeal carcinoma

“…Intensity-modulated radiation therapy (IMRT) was a milestone development in RT technology, as IMRT can provide a high conformal radiation dose to the tumor target area while effectively decreasing the dose to the sur-rounding normal tissues. IMRT, instead of 2-dimensional RT (2-DRT) and 3-dimensional conformal RT (3-DCRT), is currently more commonly used to treat NPC, due to the associated better tumor control and lower RT-related toxicities [1][2][3][4][5]. The 5-year overall survival (OS), 5-year local relapse-free survival (LRFS), 5-year regional relapse-free survival (RRFS), and 5-year distant metastasis-free survival (DMFS) rates of patients with NPC treated with IMRT ranged from 74% to 84%, 83% to 95%, 91% to 97%, and 83.3% to 85.6%, respectively [6][7][8][9][10].Both loco-regional relapse and distant metastasis are the main reasons of treatment failure in patients with NPC [6-10].…”