A Study Of Conventional Radiotherapy And Three Dimensional Conformal Radiotherapy On Latter Course For Nasopharyngeal Carcinoma

Purpose: To evaluate the treatment method of conventional radiotherapy and three dimensional conformal radiotherapy on latter course (CR+3DCRT) for patients with advanced nasopharyngeal carcinoma in order to aid clinical therapy.Methods and materials: During January 1999 to October 2002,36 primary nasopharyngeal carcinoma patients were treated by CR+3DCRT. All patients initially received conventional radiotherapy (CR) up to 50-70GY of nasopharynx followed by 3DCRT to boost up to 8-35GY(mean 19.4GY). Time of follow-up lasted range 6 to 49 months. Also CR+3DCRT treatment plans were compared with CR on radiotherapy planning and designing system for 15 patients selected at random from 36 patients.Results: With CR+3DCRT, the volume of planning tumor target(PTV) included over 95% prescription dose and the dose of95% volume of PTV obviously increased, but the 5% PTV in the maximum dose region dropped obviously. The dose of parotid glands, temporo-mandibular joints, brainstem and two eyes dropped as well. When overlap distance among target to spinal cord or brain stem≥0.5cm, patients with invaded posestyloid space got the dose of 95% target volume, which increased by 25.3%. 1~2-year survival rates were 100% and 95.6% respectively, and 1~2-year distant metastses-free rates and local control are all 97.2%.There is no Grade 3 or 4 acute toxicity in all patients. Only one patient experienced 3 late toxicity and the others had Grade 1 or 2 late toxicity.Two patients developed radiation encephalopathy.Conclusions: 1. The dose of PTV with CR+3DCRT was more homogeneous than CR. And the dose of parotid glands, temporo-mandibular joints, brain stemand and two eyes all have obviously decreased. 2. There are very effective preliminary clinical treatment results within the group. 3. As nasopharyngeal carcinoma patients, posestyloid space were invaded, we recommend CR+3CDRT. Especially when overlap distancebetween target to spinal cord or brain stem＞0.5cm, we consider that CR+3DCRT can be used for a routine therapy. 4 we suggest that 3DCRT can be treated only after NPDT 50GY of CR, and single division dose of 3DCRT muse be＜4GY/fraction.5 we suggest that patients with skull base erosion were treated by standard fractionation radiotherapy.