Résumé
Objective To investigate the late toxicities after intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma and analyze the risk factors for treatment complications.Methods A total of 299 patients with nasopharyngeal carcinoma were given initial IMRT.The nasopharyngeal lesion and cervical lymph nodes were given a prescribed dose of 70 Gy ; the dose was 60 Gy to subclinical region ; the prophylactic dose was 54 Gy to the lower neck and supraclavicular region;these doses were given in 30 fractions over 6 weeks.The clinical records of 176 patients followed up were analyzed.The hazard factors were analyzed with Logistic method.Results The median follow-up was 52 months,and the follow-up rate was 99.7％.The most common radiotherapy-induced toxicities were xerostomia and hearing loss,with incidence rates of 54.5％ and 61.4％.The incidences rate of grade 0-1 adverse reaction of skin,subcutaneous tissue,or nasopharyngeal mucosa was 91.5 ％,93.2％,or 97.2％ ;the incidence rate of grade 1-2 trismus was 3.4％.Severe complications included cranial nerve injury (5 patients) and epistaxis (2 patients,one dying due to profuse epistaxis).The hazard factors for xerostomia and hearing loss were chemotherapy (x2 =7.38,P =0.007 ; x2 =7.96,P =0.005) and median doses to the parotid gland and inner ear (x2 =4.09,P =0.043 ; x2 =7.96,P =0.005).Conclusions Most patients develop only mild toxicity of the skin,subcutaneous tissue,or nasopharyngeal mucosa after IMRT.The incidence rates of xerostomia and hearing loss remain high owing to radiotherapy dosage and chemotherapy.
Résumé
Objective To study long-term outcome and prognostic factors of nasopharyngeal carcinoma treated by intensity modulated radiotherapy.Methods A total of 299 patients with nondisseminated nasopharyngeal carcinoma who received initial radiotherapy were analyzed retrospectively.The primary lesion and the upper neck received 70 Gy (5 fraction per week in all 30 fraction) by intensitymodulated radiotherapy (IMRT).The lower neck and the supraclavicular fossa was given 54 Gy (5 fraction per week in all 30 fraction) by a single anterior tangent field with spinal cord block.A median dose of 9.2 Gy (4-20.Gy) was given to the residual primary lesion by IMRT or X-knife.The Kaplan-Meier method was used for calculating the overall survival (OS),disease progression-free survival (DPFS),distant metastasisfree survival (DMFS),Log-rank test was used for evaluating the differences between groups.Multivariate prognostic factor was analyzcd by Cox method.Results The follow-up rate was 99.7％.119 patients were followed-up more than with 5 years.The 5-year OS for stage Ⅰ + Ⅱ,stage Ⅲ and stage Ⅳ were 97.1％,82.7％ and 52.2％(x2=46.19,P=0.000),the 5 years DPFS were 100％,77.6％ and 57.7％ (x2=23.29,P =0.000),DMFS were 100％,82.3％,63.7％ (x2 =16.57,P =0.000) respectively.The 5 year OS,DPFS and DMFS of male and female were 70.7％ vs 94.1％ (x2=16.82,P=0.000),71.5％ vs 87.3％ (x2 =4.74,P =0.029) and 77.2％ vs 89.7％ (x2 =4.38,P =0.036) respectively.For patients who were younger than 45-years,the male had a significantly unfavorable 5-year OS (66.8％ vs.91.2％,x2=7.07,P=0.008),DPFS (59.9％ vs.91.2％,x2=7.72,P=0.005) and DMFS (66.4％ vs.94.0％,x2 =8.46,P =0.004) ;For patients who were old than 45-years,only OS was significantly different between male and female (72.2％ vs.96.0％,x2 =10.19,P =0.001).Multivariate analysis showed the independent prognosticfactors for OS,DPFS,DMFS,were gender (x2 =14.27,5.72,17.64,P =0.000,0.017,0.000),TNM stage (x2 =5.33,15.70,10.57,P =0.021,0.000,0.001) and lymph nodes capsular invasion (x2 =4.30,11.08,21.24,P =0.038,0.001,0.000).Intracranial invasion and supraclavicular lymph node metastasis were independent prognostic factors for OS (x2 =13.32,5.38,P =O.000,0.020).Conclusions The TNM stage,lymph nodes capsular invasion and gender are independent prognostic factors for nasopharyngeal carcinoma treated by intensity-modulated radiotherapy.The patients of younger than 45years own a worse outcome.