Objective:
To study the efficacy of stereotactic radiosurgery in salvaging early-stage persistent and recurrent nasopharyngeal carcinoma (npc) after primary radiotherapy.
Methods:
A prospective single-arm study evaluating the response and outcome of patients with rt1-2 npc treated by stereotactic radiosurgery. eleven patients with rt1-2 were treated by radiosurgery between march 1998 and march 2000. four patients were treated for persistent disease occurring within 4 months after primary radiotherapy, six were treated for first recurrence, and one for third recurrence. six patients had rt1 disease and five had rt2 disease. most patients had disease not amenable to brachytherapy, surgery, or external re-irradiation. the median target volume was 5.8 cc (range, 3.3-16.9). radiosurgery was performed with multiple noncoplanar arcs of photon, with a median dose of 12.5 gy delivered to the 80% isodose line (range, 12-14 gy). median follow-up time after radiosurgery was 18 months (range, 9-30).
Results:
Nine patients had complete regression of tumor as assessed by imaging, nasopharyngoscopy, and biopsy; one patient had partial regression of tumor; whereas one patient had static disease. the overall response rate was 91% (10 of 11) and the complete response rate was 82% (9 of 11). two patients with complete response subsequently had local relapse develop, with one recurrence outside the treated volume 8 months after radiosurgery, and the other within the treated volume 6 months after radiosurgery. one patient with a partial response had neck node recurrence develop. temporal lobe necrosis occurred in one patient but probably represents sequelae of primary radiation after reviewing the dosimetry. ten patients are still alive, whereas one patient with local relapse had distant metastases develop and died. the estimated 1-year local control rate after radiosurgery was 82%.
Conclusions:
Our preliminary results indicate that stereotactic radiosurgery is an effective treatment modality for persistent and recurrent t1-t2 npc, and early control rate seems to be comparable to other salvage treatments. more clinical experiences and longer follow-up are still needed to validate our results and to address fully the role of radiosurgery in salvaging local failures of npc.