[Therapeutic effects of three-dimensional conformal radiation therapy for locally recurrent nasopharyngeal carcinoma].

OBJECTIVE

To evaluate the feasibility of reirradiation for recurrent nasopharyngeal carcinoma (NPC) using three-dimensional conformal radiotherapy (3-D CRT) and to assess its short-term therapeutic effects and the lesions in association with radiation exposure.

METHODS

Between July 1998 and October 2000, 42 NPC patients with recurrence after their initial radiotherapy received retreatment with 3-D CRT. The radiotherapy was designed by 3-D treatment planning system and dose-volume histogram (DVH) was used to verify and optimize the radiation plan. Multileaf collimation technique and immobilization devices to fix the position of the head were used to achieve validity and accuracy of radiotherapy. The planning target volume (PTV) encompassed 7~10 mm safety margin, with a median volume of PTV of 47.6 cm3 (27.9 to 61.8 cm3), and 5 to 7 static conformal portals were delivered with coplanar or non-coplanar irradiation technique. The prescription dose-fractionation-time was 60-70 Gy/24-28 F/5-5.5 weeks, with the median follow-up time after 3-D CRT of 24 months (ranging from 10 to 38 months).

RESULTS

No evidence of local failure was found in 85.7 % of the cases after 3-D CRT and the 2-year survival rate was 73.8 %. The lesions resulting from the radiation included hearing loss, trismus, dysphagia, chronic sinusitis, and cranial neuropathy, at a rate of 7.1 %, 35.7 %, 7.1 %, 28.6 %, and 21.4 % respectively.

CONCLUSION

3-D CRT is effective and feasible to treatment of recurrent NPC after initial radiotherapy, producing good responses without serious complications. The long-term survival and possible specific injury, however, need to be further investigated.