The importance of the optimal volume in the treatment of locally recurrent nasopharyngeal carcinoma; brachytherapy or stereotactic radiotherapy?

Document Type: Conference Proceedings

Author

Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran

Abstract

Introduction:
Nasopharyngeal carcinoma (NPC) is commonly known as a radiosensitive tumor with the initial good response to radiation.
Despite the improved outcome in loco regional control by the introduction of combining treatment, modern radiotherapy techniques and enhanced imaging studies, local recurrent after primary treatment with rate ranges from 15-58% in 5 years, still remains one of the major causes of failure for patients with NPC.
Re irradiation with various treatment modalities have been reported as a salvage option of NPC recurrent. Considering Limitation of critical organ tolerance doses because of the initial radiotherapy, brachytherapy (BT) and Stereotactic radiotherapy (SRT) irradiation have been encouraging especially if the recurrent lesion is small. The techniques can deliver a highly precise dose to the tumor while minimizing radiation to the surrounding normal tissue. Incidence of severe acute and late complications in these, depending to dose per fraction, total dose, time interval from previous radiotherapy and CTV is different. We compared optimal volume and toxicity in patients with locally recurrent nasopharyngeal carcinoma treated with BT and SRT.
Materials and Methods:
We retrospectively reviewed treatment plan of 12 patients with locally recurrent NPC were treated with BT between 1394 and 1397. However, the technique is applicable only to a small volume tumor, may produce some severe complications, such as soft palate perforation, sphenoid base fistula. But BT were well tolerated with no severe acute complications in this study. Median Tumor volume was 63 cc. The results of studies conducted with SRT despite the high probability of acute complications, Local control was better.
Results:
Improved local control and reduction of complications in both methods was reported to be significant respect to other ways. But the results of Similar study SRT showed that with more fractionated dese, late complications can be reduced. Tumor volume Range of 10.3–56.2 ml in early stage recurrent had Acceptable response rate to treatment. Common Late toxicities in SRT included cranial nerve injury, massive nasopharyngeal hemorrhage, and temporal lobe necrosis. The results of this study showed that with delivery proper dose of each session and the total time in SRT, can decrease Possible late complications.
Conclusion:
It was concluded that the best outcomes with re irradiation related on limited volume recurrence. According to the results of similar experience, SRT is superior to brachytherapy both in terms of providing sufficient dose for para nasopharyngeal spread and local control. SRT currently not routinely available in Most clinics as yet, but it has great potential in future cases of head and neck cancer.

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