Changes On The Clinical Efficacy Of Nasopharyngeal Cancer IMRT Target Delineation Way After Induction Chemotherapy

Objective:Nasopharyngeal carcinoma after induction chemotherapy grosstumor volume gross tumor volume, GTVnx, GTVnd) was significantly reduced.This study investigated the effects of GTV outline ways to target and normaltissue dose and clinical efficacy by inducing changes in tumor volume afterchemotherapy, and after the change.Methods:From February2012to March2014were treated100cases of Ⅱ-Ⅳof pathologically confirmed newly diagnosed patients with nasopharyngealcarcinoma, according to the random number will be divided into the use ofinduction chemotherapy in patients with primary tumors GTVnx before andafter induction chemotherapy in primary tumors GTVnx outline target groups(group A and group B). All patients use two cycles induction chemotherapy ofPF or TP program,then second CT scan and image fusion and the developmentof tumor volume measurements before and after induction chemotherapy IMRTplan, while observing all patients toxicity and clinical efficacy.Results:Before and after induction chemotherapy the primary tumor GTVnxaverage volume was31.62±19.31cm3and19.43±12.33cm3,(P=0.003)respectively; positive cervical lymph GTVnd19.89±13.44cm3and10.51±9.60cm3,(P=0.002) respectively.After induction chemotherapy the averagereduce volume of nasopharyngeal lesions and cervical lymph nodes were36%and49%, respectively. After induction chemotherapy target delineation group(group B) normal tissue dose is lower than after group(group A), in whichDmax of bilateral lens, Dmax of bilateral temporal lobes, Dmax of rightparotid gland, D33of left parotid gland, with significant difference betweentwo groups (P<0.05). The therapeutic effect was evaluated3months after theend of radiotherapy and chemotherapy, complete remission rate ofnasopharyngeal and positive neck lymph node was95%, including2cases of nasal pharyngeal residue (1cases in each group);3cases of cervical lymphnode residual (A group1cases,2cases of group B)(P>0.05). After a medianperiod of14months (3-25months) follow-up, all the patients overall survivalrate of OS was100%; the disease free survival rate(DFS) of two groups were:92.90%vs82.70%,respectively, there is no significant difference between thetwo groups (P>0.05). The progression free survival rates (PFS) of two groupswere:92.60%vs84.60%, respectively, there is no significant differencebetween the two groups (P>0.05),there were4cases of the bone metastasis,2cases of liver metastasis,1cases of esophageal cancer in second primarytumors,1cases of breast cancer in second primary tumors, there were all N3patients;1patients with nasopharyngeal recurrent, for patient with T4; longterm toxic side toxicity of radiotherapy and chemotherapy two groups aresimilar, there was no significant difference between the two groups.Conclusion: After induction chemotherapy, the volume of nasopharyngealcarcinoma and positive cervical lymph node significantly reduced. According toGTVnx after induction chemotherapy for nasopharyngeal tumor targetdelineation of intensity-modulated radiotherapy, the target volume wassignificantly reduced, and the target dose not reducing conditions, normaltissues (temporal lobes, parotid gland, lens) dose reduction; and during thetreatment, treatment related toxicity in the tolerance range, the use of inductionchemotherapy of GTV as a tumor target plan does not affect the survival rate,also can obtain good clinical curative effect.